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22 May 2018

1. History of the development of the world famous Supertag RFID technology
2. The IOT (Internet of thing) and RF sensors such as LORA technology
3. Product range
4. Getting your own complete RFID/radar system

1. History of the development of the world famous Supertag RFID technology
My school is having a 50 year reunion for our class of 1968. The pupils had gone into a variety of different jobs and many had relocated to different parts of the world. For the past three months the organisers have been trying to make contact with surviving pupils, which is difficult as we never had any reunions before. There have been many emails between the group trying to jog memories about memorable events that happened during the five years we were together so long ago.

In looking at class photos, one realises how fickle is one's memory as I can barely recognise any of my class mates. This got me thinking that before we forget, we need to record the history of Supertag- most probably the most significant development in RFID- where a supermarket trolley full of items was pushed through a scanner and read without unpacking.

Having led the team that developed and commercialised the product, and having invented the protocol, I decided to record the history and show photographs of the early development.

It is an ongoing project but have a look at History of Supertag

2. The IOT (Internet of thing) and RF sensors such as LORA technology
There are a number of conferences taking place to discuss issues relating to the Internet of Things. If one reads through the list of papers to be presented, one finds they are by software companies relating to the processing of data, and virtually no papers relating to sensor systems to gather this data.

One of the basic concepts proposed in IOT is that there would be low cost transponders, there would be common receivers at convenient places (say cell phone towers) that would collect the data from the sensors and relay them onto the internet to the cloud (Amazon?/turned off by Trump globally at his whim?) who would store the data. You as a user would then run a subscription service with the cloud provider to retrieve your data.

One of the corner stones of the system is that the sensors would be low cost, have medium range, have long battery life, and could be placed in locations such as fields, or on animals, or floating down rivers, etc. This sensor system is called LORA. This LORA system has huge limitations which are not understood by the software companies as they have no expertise in RF systems but assume it will work to meet their data needs.. The limitations are largely due to the laws of physics and there is no silver bullet.

In the 1980s while working at CSIR we, were approached by a global software/hardware company, to provide a sensor system for labelling assets in a bank to track their equipment being removed from their premises. The company had already spent millions developing the software and just lacked a sensor system. We could not help as the software was about ten years ahead of the sensor developments at that time. I suspect IOT is in a similar position with the sensors being ignored and everybody developing the software.

More about this in later newsletters where we will go more into the LORA system.

3. Product range
Trolley Scan are a manufacturer of UHF RFID systems.

Trolley Scan manufacture fixed readers, portable readers,solar powered readers, and RFID-radar systems (Real Time Locating systems that give accurate position information) as well as a variety of transponders for different applications. Transponders come in the form of passive transponders with operating ranges up to 20 metres and battery assisted transponders with an operating range up to 40 metres. Trolley Scan also combine some of these components into packages for end users which are supplied with the appropriate software. Typical applications are asset management, notebook tracking, equipment barriers, store control, wild game and cattle monitoring, event logging and sports timing systems.

Trolley Scan have been delivering their RFID solutions for the past 18 years and offer full support for all their equipment.

4. Getting your own complete RFID/radar system
You can order RFID systems or RFID-radar systems from Trolleyscan.com

Trolley Scan provide small RFID reader systems which give new users the ability to evaluate UHF RFID and their applications without needing specialised skills.

Trolley Scan provide a variety of easy starter systems for first time users who have an application that needs a solution. Typical packages are :

  • Standard UHF long range readers with antennas and 100 transponders
  • RFID-radar system comprising long range reader, antennas and a variety of different transponders.
  • RFID-asset tracking systems comprising portable reader, antenna and a variety of transponders with software.
  • RFID-notebook/laptop tracking system comprising reader, antennas, transponders and software
  • Solar powered RFID reader systems for monitoring livestock. In addition components such as readers and transponders are available
  • These systems are already operating in 52 countries.

    24 May 2017

    1. Development of RFID work in progress tracking system
    2. RFID system for tracking assets for capital registers
    3. Solar powered Eco-antelope system entered in Innovation award competition
    1. Development of RFID work in progress tracking system
    In manufacturing plants it is important to track progress of the items being produced so that the information can be integrated into the management plan. In a single product production line this is relatively easy as parts move down a single production channel.

    In a machining factory where there might be hundreds of products in production from tens of production machines, such as lathes or moulding machines - this is much more complex as there are so many measuring points.

    Trolley Scan have developed a system using a single portable reader that is operated by a single operator that logs the current position of all jobs in the production workplace and feeds this information back into the management system for the plant. With this system, called RFID-WIP, frequent updates of progress are possible with minimal additional infrastructure.

    For more info mailto:info@rfidradar.com?subject=News107_Want_info_on_RFID-WIP

    2. RFID system for tracking assets for capital registers
    As part of financial control, organisations are required periodically to verify the location and existence of items on their capital register. In large organisations these might number thousands of items spread across many buildings.

    Trolley Scan have a product called RFIDasset that uses the long range capabilities of RFID systems to gather information about the current location of items and map their current location. This enables a single operator to do a sweep of buildings quickly and document the current location of the items quickly, reporting all missing items at the same time.

    Our largest installation to-date covers assets distributed in 27 buildings. We recently have installed a system for a client with more than forty thousand items to be tracked on their capital register. An additional feature added to the system is the creation of "shipping lists" where the transfer of items from one section to another via a single shipment is tracked and ensures that no item goes missing from the transfer.

    For more info mailto:info@rfidradar.com?subject=News107_Want_info_on_RFIDasseet

    3. Solar powered Eco-antelope system entered in Innovation award competition
    Many farmers of cattle and wild game hire fields for grazing from other land-owners. These fields are often very far from their farm and farmhouse, and are often unattended due to their remote location. Trolley Scan have created their Eco-antelope product which monitors the animals in the remote field and reports the presence of the animals back to the farmer via a server on the cloud. The Eco-antelope reader is designed to operate in areas where there are no utilities, such as power or telephone communication. Energy for operation comes from solar power and communication is done via GPRS modems via the cellphone network. The animals are tagged with a special eartag that contains a passive transponder with a very long operating life, so that the animals do not need to be handled once the transponders are attached. Trolley Scan have entered this system in the MTN Business IoT Conference & Awards in South Africa. For more info mailto:info@rfidradar.com?subject=News107_Want_info_on_Ecoantelope

    15 July 2016

    1. Development of Solar-powered standalone UHF RFID reader
    2. Complete remote UHF RFID systems for farm applications coming shortly
    1. Solar-powered standalone UHF RFID reader
    At the request of some farmers wanting to monitor their livestock in remote fields, Trolley Scan have developed a solar powered RFID reader that works in conjunction with the existing Eco-cattle(tm) eartags to provide a self contained RFID systemwith a 10 meter reading range. The system can be located in a distant location that does not have the conventional utilities such as power and communications.

    Although solar power and batteries are well-known technologies, making a RFID reader that can work with these technologies has been a major challenge. A reader operating on solar power has to be able to handle serious power fluctuations when the solar batteries are discharged. The reader has to be able to sense the condition of the batteries, and when they hold sufficient energy, to restart the entire system and to re-establish communications with the remote computer systems. The reader has to send status messages in the dying and coming to life phases so that the remote computers are aware of the current status of readers.

    Conventional battery technology and charging systems are not suitable as there might be long periods due to weather when there will not be sufficient solar energy to operate the system and the batteries might discharge to zero volts. To cater for these situations a special battery technology has to be used that can handle full discharge and even over-charge but still gives about a 20 year life.

    The components of the reader had to be redesigned to handle lower operating voltage which is available from solar systems.

    For communications we have made facilities to communicate either via cellphone networks OR point to point radio communications OR even via wire. The reader has to deal with the challenges of establishing communication, especially in the cellphone network situation where the network might be out of action.

    Although this reader has been targeted at farmers both of cattle and wild game, it also has application in other situations where RFID systems are needed in remote situations where there are no power utilities.

    The UHF reader works with the entire range of transponders that are made by Trolley Scan

    For more info mailto:info@rfidradar.com?subject=Want_info_on_solar_reader

    2. Complete remote UHF RFID systems for farm applications coming shortly
    In our next newsletter we are expecting to announce the availability of the Eco-antelope(tm) complete systems for farmers. It provides the hardware and software to allow farmers to monitor remotely on the web from any location, the presence of their animals in a remote field. It makes use of the solar powered UHF reader and the Ecocattle transponders giving up to 10 metre reading ranges of animals passing near the UHF reader.

    14 May 2016

    1. Development of passive UHF RFID animal eartag for cattle and wild game

    1. Development of passive UHF RFID animal eartag for cattle and wild game
    RFID systems have two major components, namely the reader and the transponder. If there is a suitable transponder available for a particular application, then RFID solutions can be provided for that industry.

    To attach transponders to large animals such as cows or kudu, if you are wanting to get a reasonable read range, then the transponder needs to be outside of the body. (The water content of the body means that only magnetic coupled transponder technology can be used when the transponder is inserted under the skin and these have very short read ranges.) To get the transponder mounted outside of the body, it is usual to attach the transponder to the ear tag on the animal. This presents problems in the past as it is very difficult to glue anything to an eartag due to its material of manufacture, and the performance of the transponder changes when it is in close contact with the material of the eartag meaning short read ranges.

    Trolley Scan have developed a UHF passive RFID transponder that now has a read range up to 10 meters. The transponder is moulded inside the eartag protecting it from damage and giving the RFID eartag a long operating life. The eartag is passive - so no batteries are needed - and the electronics should have a 100 year life.

    The eartag is based on the standard range of eartags produced by SafeTag in East London, South Africa and comes with all the supporting equipment needed to apply the tags in the field. This includes having the ability to have the animal number marked on the eartag with a laser etching process for permanent marking.

    To develop this transponder, Trolley Scan faced a number of challenges. An antenna needs to be very efficient to offer long reading ranges and this means it must resonate at the operating frequency. This is similar to the situation of a tuning fork in an audio situation. The antenna is influenced by materials in close proximity to the circuit board and by other items in its environment up to 9 centimeters away from the circuit board. These influences change the operating performance of the transponder compared to when it is operating in air such that when attached to the eartag all the performance has disappeared. This meant that a new design of the transponder had to be developed by Trolley Scan to compensate for all these influences and to get back the transponder performance that it would be able to be read at 10 meters from the reader when attached to the animal. This required a new design as the transponder is now embedded inside the eartag material and is influenced by the moulding material on both sides of the transponder.

    This development opens opportunities for monitoring of large animals up to 10 meters from the reader and is particularly suited to unmanned monitoring of animals on a continuous basis.

    More details can be found at Datasheet - Bokkie-tag(tm)/Ecocattle(tm) passive RFID eartag for wild game and cattle

    19 December 2015

    1. Using RFID to mark safe routes through landmines for vehicles - request from United Nations

    1. Using RFID to mark safe routes through landmines for vehicles - request from United Nations

    The following is an extract from the 38 page RFP:

    The United Nations (UNOPS) has issued a Request for proposal and plans to procure Radio Frequency Identification (RFID) equipment to demarcate roads and allow vehicles to automatically follow such markers.

    The border between Sudan and South Sudan is estimated to be approximately 2200 km long and according to the UNISFA mandate, the UNISFA is to establish and patrol this border together with National Monitors from both Sudan and South Sudan. The border has never been physically marked or if marking had been done before, it would have been done during the colonial occupation of Sudan.

    The UNMAS marking methods as prescribed in the International Mine Action Standards makes provision for a series of marking systems to be utilised when marking a cleared area prior to handing it over to the relevant authorities or the end user. These systems include the following:
    a. Visual Reference Points
    b. Visual constructed Bench Marks
    c. Visual and sub-surface Starting Points
    d. Visual and sub-surface Turning Points
    e. Visual and subsurface Intermediate Points
    f. Sub-surface marking by insertion of metal rods in ground to be located with a metal detector at all above mentioned Points
    g. Accurate mapping of area

    In addition, the above-mentioned points are linked on maps with the relevant distances and compass bearings between them. The coordinates of these points are also recorded either with handheld Global Positioning System (GPS) or for more accuracy, a Differential Global Positioning System (DGPS).

    Over the years, marking systems within the Mine Action environment has been problematic and sustainability of marking has been subjected to the following factors:

    A. Climatic conditions: Extreme weather conditions, such as high temperatures reduce the durability of visual markers. Painted pickets, rocks, barrier tape etc. are eroded by extreme temperatures, wind and rain and therefore lose the ability to be utilised as visual marker over a short period of time. Rain and floods also wash away marking over a period of time.

    B. Theft: Theft is one of the biggest problems experienced with the marking of cleared or hazardous marking, especially in under-developed areas. Theft occurs when the marking materials have a monetary value, a use as a souvenir (for example mine warning signs) or as in many instances children use material from marking systems to be utilised in making toys. When hazardous areas are being fenced off with metal barbed wire, these wires are sought after for farmersí fences and safekeeping of cattle for example.

    C. Bush Fires: In rural areas in the country, bush fires are seasonal occurrences. Prior to rainy seasons, local population such as cattle herders, farmers etc. will burn vast areas to ensure better grazing after the onset of the first rains. The fires are normally uncontrolled and burn and destroy any visual marking. Those type of marking that is not destroyed, are normally burnt to such a state that it is unrecognisable.

    D. Intentional removal of marking: In areas where there are political differences, armed conflict or other unresolved land issues between the population, removal of any marking of hazardous or clearance marking can occur. Furthermore, is can also be removed by groups to deter opposition groups to enter an area and therefore create doubt in the opposition group as to the exact location of hazardous areas.

    Until such time as there is well established routes or constructed roads, the identification of exact tracks or areas cleared by UNMAS will be problematic, especially after marking has deteriorated or been destroyed by mentioned factors including rain, theft etc.

    Navigation by normal handheld GPS as well as DGPS by unqualified persons can be a tedious task and increases the risk of entering hazardous or dangerous areas. The use of DGPS is also very expensive, brought about by licencing fees, equipment and training. In addition, due to the periodic rotation of military personnel within the JBVMM Mission, local knowledge of the Area of Operations is also lost.

    During research to find a sustainable and cost effective solution to the described marking problems, UNMAS concluded that utilisation of Radio Frequency Identification Service (RFID) will be the best way to the unique environment and challenges in demarcating the border and cleared areas within the border.

    As RFID is an established and proven commercial technology, UNOPS (UNMAS/UNISFA) has the requirement to procure existing RFID technology and equipment that can be adapted in a cost effective way to be utilised in the UNMAS/UNISFA programme for the demarcation of the border area between Sudan and South Sudan. The successful company will provide the technology, equipment and the training for the implementation of the initial stage of the programme.

    Phase 1:
    The estimated length of the route for the phase I of this project is 100 km, which will be a combination of gravel roads, as well as extreme off road bush paths. The bidders will determine the quantity and the type of equipment necessary to cover the total length of the route. At the Phase 1, it is estimated that five (5) Radio Frequency Readers (scanners) will be sufficient to carry out the task. The scanners should easily locate these buried tags. Bidders should be able to guide the right location where tags are needed. The Reader will have a LED/LCD or a similar display screen, which will indicate to the driver/patrol that they are following the route accurately while in motion at the estimated speed of 40 km per hour
    Phase 2
    Planned to extend the coverage to 1000 km.

    The above RFP was received from UNOPS by Trolley Scan on the 18th December 2015. We are one of the companies that were approached by the UNOPS about the concept.

    Depending on the operating frequency and factors such as water content, RFID energy does penetrate the ground and allow buried transponders to be located with a reader.

    One regular application of this approach is in locating the manholes for buried trunk fibreoptic cables. In these situations the cables and the access manholes are covered with soil after installation. The manhole covers are tagged with RFID transponders and in the event of maintenance being needed, the technician uses an RFID reader to locate the transponder and hence the manhole which can then be uncovered providing access.

    Passive transponders would most probably be needed top be protected by suitable packaging and buried in the roadway. The lead vehicle in the convoy would have a reader system which would detect the transponder and provide identity and tracking information to the vehicle providing location information and guidance.

    In a similar project Trolley Scan provide systems for unmanned trains that continuously read transponders along the track to control their speed and provide location information for command and control.

    "This application could be one of the largest unconventional consumers of RFID todate."

    Want more info. If you contact Mike Marsh at Trolley Scan we can provide you with a copy of the RFP from UNOPS.
    The closing date is in a couple of weeks.

    18 October 2015

    1. The rewards of using established component suppliers

    1. The rewards of using established component suppliers
    For those of you not aware about the features of RFID radar - it is an amazing RFID system that can give the identity and position of transponders in its field of view, with accuracies of millimeters at ranges up to 40 meters. To do this it does not use any classic radar type approach of pulsed systems, or features such as power measurement, but rather uses very low interference techniques that allow precise measurements while allowing many systems to operate in close proximity. This is achieved by a very special design, using special high quality parts and four digital signal processors running about 75000 lines of code.

    The performance of the Radar is exceptional in that during its soak testing, we monitor thousands of readings and find very minor data scatter even at 40 meters.

    As the designer and manufacturer of the systems, we have come to appreciate working with mature component suppliers that can keep on making the special parts we use over the ten year period we have been making the system. Although manufacturers might bring new versions of products to market, as a system manufacturer it is essential that we are also able to get the older versions that have already been qualified for use in our systems.

    The RFIDradar uses some very special parts that have specially been designed and manufactured for us. We hold stocks of these parts but when it comes to re-ordering, some of the manufacturers have to do a special manufacturing run for our parts as they are not off the shelf parts. This in some cases needs a 90 day turn around between the order and delivery as the parts are carefully tuned to deliver the required performance. This is where one appreciates dealing with companies that have been in business for decades and have the skills and resources to make special parts for customers.

    Like our suppliers, we deliver stand alone systems that will work with past, current and future generations of computers and software, providing reliable measuring data for computer systems. We support our clients from 52 countries with support covering our earliest generations of equipment to our current. Any client can contact us with a problem and we will be able to get their system to full operation.

    Although our design has been stable for many years, the recent banning of transport by air of equipment containing lithium batteries caused a redesign of the battery powered transponders to allow the batteries to be removed before shipment. This allowed us to also improve the performance of the transponders. The systems will work equally well with the older and the newer transponders but should get slightly more range with the newer generation.

    22 June 2015

    1. Interesting projects using RFID - RFID controls unmanned heavy vehicles

    1. Interesting projects using RFID - RFID controls unmanned heavy vehicles
    RFID is a sensing system that can be used with computer systems to provide some very useful systems.

    For the past ten years, Trolley Scan have been providing adapted readers with special software, that allow unmanned trucks to move heavy loads very safely.

    RFID can allow heavy vehicles to sense their current position when moving along a roadway and by knowing the distance between transponders and the time they are read, the speed can also be determined. This can be an independant system that does not need external signals such as GPS, and will also work when moving inside buildings.

    Transponders are attached along the track and a reader on the vehicle detects the identity of each transponder as it passes over them. The computer system inside the vehicle has a table of the correct order the transponders will be passed and can detect immediately there is any component failure. The reader software has been specially created to provide status information to the computer controller so that any failure can immediately be detected.

    The system uses passive transponders so that there is no maintenance involved in keeping the RFID system operational.

    About 20 of these systems are in operation and the project has been running for the past ten years.

    12 August 2014
    1. Development of new range of transponders for radar
    2. Using RFID-radar to steer robots

    1. Development of new range of transponders for radar
    In our earlier newsletter we reported that the freighting world had changed dramatically for shipping electronic goods as of the 1st April 2014. From that time on it has become extremely difficult to airfreight any electronic item that contained any form of battery. Any battery that used lithium was marked for special attention and was regarded as a hazardous cargo, and was not allowed in some countries to be shipped on an aircraft that carried passengers. We had two systems caught in transit by these new regulations, namely one being moved by a global courier and the other by a freight forwarder. Instead of taking a few days to do the shipment as in the past, it took nearly 30 days each for those two shipments to be delivered. The freight forwarder had his shipment rejected on three occasions by the airlines despite the goods having all the required hazardous cargo certificates. Eventually he shipped via a third country to bypass one of the bottlenecks. All this was over 18 very small watch batteries that were in the battery assisted transponders. These are long life batteries and are built inside the transponder in manufacture to power up the devices for five years. It seems that lithium is a particular problem for the airlines as their existing fire extinguishers have trouble dealing with a lithium fire. With the goods being classified as hazardous cargo the shipping cost are much higher than normal.

    Trolley Scan have redesigned the battery assisted transponders in their product range to allow access to the batteries from outside the transponder. In the past the battery was inserted in the middle of the structure during manufacture, and was then encased in plastic and rubber to make a waterproof device. In the new design, a battery holder has been included in the case design so that the battery can be inserted and removed.

    We now build the devices to order, soak test the devices, and then remove all the batteries prior to shipment. The client buys the same batteries from their local supplier and fits the batteries when the system arrives.

    This is not an ideal solution as the waterproofing of the transponder has been compromised but it does allow the equipment to be delivered.

    2. Using RFID-radar to steer robots
    The RFID-radar has the ability to measure the angles of arrival of signals reaching the reader from a number of transponders virtually simultaneously. The range measurement to the transponders is speed limited and usually our clients are wanting to travel at a higher speed than the range features allow.

    The clients want to make robot systems that can operate over large warehouses freely.

    By placing many transponders around the area in which the robot will be operating, the robot is able to read the angles from many transponders at any instant, and from the angles of arrival solve its current position.

    The reader does not do any of the solving of the position, but reports all the angles to a host computer on the robot which then does the position solution.

    To build this system you need computer skills as you are processing complex geometric situations and there will also be an element of fuzzy logic to deal with obstructed radio paths and possible some multipath.

    28 April 2014

    Your latest copy of our regular newsletter keeping you up to date with developments. Contents
    1. Major changes to world trade in the past month
    2. Energy conversion

    1. Major changes to world trade in the past month
    This weekend we have two radar systems in transit to overseas clients both with complicated shipping arrangements. Whereas we have shipped in the past about 500 such systems using couriers, the 1st April saw the introduction of new rules and measures that make the shipping of some goods nearly impossible. Even a major courier company like FEDEX said they could not transport the systems with the new rules.

    Inside most watches, calculators, computer motherboards and virtually any device that can remember a date setting, lies a small coin cell battery that keeps the date chip running. These cell batteries usually contain lithium in small amounts to give a battery that has very low leakage and usually a five year operating life. It is these batteries that are the target of new regulations from the 1st April which make their transport by air or sea extremely difficult.

    Since 2013, IATA (the airline association) has introduced new regulations that declared any form of lithium battery as a dangerous cargo. Prior to the 1st April, the small coin cells mentioned above were excluded in certain circumstances, but from the 1st April this exemption falls away and any item that includes one of these batteries is now classified as dangerous cargo and subject to new transport regulations. In most cases this involves special packaging, a limit on the number of batteries in the package, special labelling of the cargo and an accompanying lithium battery certificate even if the battery is encased inside an electronic system.

    In the USA situation, for local transport, import or export, this cargo may not be transported on any passenger aircraft and can only be moved by "cargo only" aircraft.

    There are further regulations concerning the lithium batteries, requiring them only to be made in approved UN certified factories.

    In our radar system we provide transponders that have a 40 metre range and which contain one of these small batteries. The batteries are installed in manufacture and are deep inside the packaging of the transponder before the transponder is finally encased in a rubber sleeve. They are electrically disconnected during transport and are not accessible from outside the transponder.

    The new transport rules are going to mean that we change the design of the transponder to either:-

  • 1) use a different chemistry rechargeable battery and supply a recharge circuit for users to recharge the encased battery. The leakage for rechargeable batteries is much higher than lithium batteries and typically a rechargeable battery will run flat in a storage situation in 3 months compared to the five years of a lithium battery.
  • 2) use an externally accessible battery holder so that the user can locally buy lithium batteries and install them themselves when they receive the equipment. We can then fly the equipment with no batteries included. This solution is further complicated in that the positioning of the battery in the transponder is critical in order to preserve the RF performance and its waterproof nature.
  • 2. Energy conversion
    A really impressive technology is developing at present relating to the useful conversions of solar energy.

    Solar panels are becoming quite cheap and have a long operating life (20 years if well made). However they are difficult to interface to harness the available power. A typical panel might have an open circuit voltage of 22 volts, a short circuit current of 3 amps and have an optimum power transfer point elsewhere say at 15 volts. In addition a cloud passing across the direct sun path might cause the output power to drop to just 10% of the energy compared to the energy without the cloud. All this means that one is getting continually fluctuating energy from the panels and it is very difficult to design for a steady load- especially something using a motor.

    In the past one might have stored the energy in some form of battery, but this gives very little of the potential energy available from the solar panel to a useful load. Batteries are expensive, difficult to charge and discharge quickly, have small capacities and a limited life.

    The ideal situation is to immediately convert the solar energy to mains electricity that is compatible with the supplied mains and to use the energy in the normal AC load of the building, reducing the amount of energy drawn from the municipal supply.

    You cannot use any inverter to convert the DC voltage from the solar panel to AC mains compatible energy. It has to be generated in exact phase and frequency with the incoming mains otherwise it is going to be vaporised.

    The type of inverter needed is called a Grid-Tie inverter.

    It is wired directly onto the mains supply and the solar panel provides the energy. The inverter continually monitors the solar panel and as soon as there is sufficient energy it starts to monitor the AC mains supply determining the frequency and the phase angles.

    It starts its inverter at the same frequency as the incoming mains supply but at a low output voltage and gets the two voltages in exact phase with each other. It then increases the output voltage to start supplying in phase electricity and using up the available solar power.

    On the solar input side it adjusts the load voltage to get maximum power transfer from the solar panel by monitoring the DC voltage and current to operate at the Maximum Power transfer point. It continually adjusts these values so that it can handle variations in the available solar power such as might happen with a cloud passing through the direct sun path.

    The inverter has another feature called islanding, which shuts down the entire process in the event of an incoming mains failure.

    Grid-Tie inverters have been around for a long time for major solar and wind turbine installations. They have however been quite expensive (US$1500 for a 15KVA system)

    The new development is in the form of micro grid-tie inverters which allow simple systems of 300 watts or 500 watts to be implemented in modular form. These are not wired into the main switch board of the establishment, but plug into a normal AC outlet in a room. They are also cascadable allowing many 300 watt or 500 watt units to work in parallel so that larger loads can be addressed. They also cost only about US$100 each.

    We have three of these systems running at present which generate about 40% of the electricity used during daytime. We have power meters on the incoming mains power supplied from the municipality and on the power supplied from the solar panels and continuously monitor the effectiveness of the system. When clouds pass over the setup one instantly observes the change in output from the solar network and the increase from the municipal network to keep the building load running optimally.

    Electricity meters that monitor the incoming supply from the municipality supply are becoming electronic based rather than the historic magnetic type. The electronic meters cannot determine the direction of the current flow and so it is important that one does not generate more electricity from the solar network than the building is using as any oversupply will flow back into the municipal network and generate a charge on the meter despite no electricity being used. Hence during times of full sun one can reduce the municipal consumption down to nearly zero using the grid tie inverters, but in cloudy conditions or when night falls, the building needs to run on municipal supply.

    At current electricity rates, we expect payback within 5 years without any form of solar subsidy.

    13 November 2013

    This newsletter is available in a PDF format as well at http://trolleyscan.com/newsl98.pdf

    1. CellID - a new form of global tracking

    1. Cellid a new form of global tracking

    If you wanted to track a motor vehicle for example, over a large distance, there have been some recent developments in equipment that allow this to be done very cheaply. This new technology uses the cell phone network to identify the location and to transfer the message from the unit back to the requester.

    Previously one would use a GPS receiver to determine the position of the vehicle, and then some form of communications system to sent the answer to the requester. The negatives of the GPS solution are the cost, that two systems are needed (namely measuring the position and communicating the result), that the GPS antenna need to be in line of sight of the GPS satellites overhead, and that it does not work in the presence of high rise buildings or when inside a building.

    The CellId systems operate where ever a cell phone signal is present, in the open or inside a building. The antennas can be inside the device which does not need to be in line of site, but can for example be built into the bodywork of the vehicle.

    The CellId device is a spin off of cellphone technology. It can be packaged in a unit as small as 3cms x 3 cms by 1 cm, of which most of the volume is the battery system. It holds a SIM card which connects it to the cellphone network to read the location and to provide communications. The device is activated by sending an SMS from the requester to which it replies with the current position. Other versions include a vibration sensor which can initiate an SMS whenever the device is moved.

    Each cellphone tower, when communicating with a cellphone device, communicates the country code, the service provider code, the local area code and the cellid of the tower.

    The format looks like mcc=655,mnc=001,lac=150,cellid=15262.

    This represents the position of the tower which is communicating with the cellid device and typically is about 500 to 2000 metres from the cellid device.

    Various websites convert the above data back to a lat lon position of the tower and plot it on a map.

    A weakness of the system is that the database of the cell towers is not freely available in many countries and the individual service providers are not compelled to provide the information to the public. This has resulted in various volunteer organisations creating a public database by their volunteer members finding towers, extracting the cellid data from the communications with their cellphone, and submitting the description and location to the database for others to use.

    Trolley Scan DO NOT make the cellid devices, but we have been using them and testing them for the past few months. They are hugely useful for locating vehicles out on delivery or the like, where the exact position is not important but one wants to know approximately where on the delivery route the vehicle is currently.

    They are very cheap to operate and are very cheap to buy, and do not need a third party service provider to realise the service. They also can be used to locate stolen vehicles, being built into the bodywork and only activated in the event of a theft.

    6 June 2013

    This newsletter is available in a PDF format as well at http://trolleyscan.com/newsl97.pdf

    1. Tracking nuclear storage containers
    2. Server attack - hitting the beehive

    1. Tracking nuclear storage containers
    Many countries store their spent nuclear fuel from their nuclear power stations in metal and concrete drums which are then buried underground.

    Trolley Scan were sent a few months ago a request by a nuclear plant operator to propose equipment for a system to track these containers using RFID. The tracking relates to empty containers before filling, filled containers on site and filled containers that are being transported to the storage area. The RFID transponders need to survive the burial process for many decades to provide positive identification of each container if they are excavated.

    The intention is to attach special transponders to the outside of the metal drums, and in the case of concrete drums to embed transponders in the concrete case.

    There are two interesting challenges to this proposal, namely the design of transponders to be buried in concrete, and protecting the transponders from the effects of close nuclear radiation.

    A properly designed antenna for an RF device resonates at its operating frequency giving effective magnification of the RF performance, in the same way that a tuning fork resonates at its design frequency to sound waves at its resonant frequency.

    When radio waves travel through dense materials, they no longer travel at the speed of light but travel slower which is a function of the relative dielectric constant of the material through which the wave is passing. This means that an antenna system that works in air will not work effectively when the antennas are encased in concrete and a new design is needed.

    Trolley Scan have experience in designing for concrete, having done a design to tag the large concrete road crash barriers used in road construction on motorways. The purpose was to provide positive identity for each concrete block and be able to read that identity while passing at speed for inventory purposes. A new antenna system was developed for the transponders which are encased in the concrete during casting and allow good reading ranges.

    Semiconductors have a problem operating in a zone of high radiation. Back in the 1960/70s before the age of microprocessors, digital systems were made primarily from a technology called TTL. This technology implemented gates, latches, counters and shift registers and from these modules computer systems were built. There were three ranges of the technology, namely commercial which could handle 0 to 70 degC, military which could handle -40 to 125 degC, and radiation hardened to be used in space applications where they might be bombarded by radiation. The problem with the radiation seems to be that it alters memory states of the modules and hence the values being stored.

    Whether this would be a problem with certain RFID systems is uncertain as there are limited facilities that can test the devices due to the radiation requirements. However there are certain RFID design issues that should minimise the impact of the radiation, such as having hard coded data in the RFID device rather than memory structures.

    Testing in-situ will have to be done before final answers can be given.

    2. Server attacks - hitting the beehive
    This section relates to some observations that would be of interest to readers who operate internet servers and please skip if not of interest.

    In our past newsletter we described how we had discovered a continual low level of security probing of our site on an organised basis from a very large number of slave computers worldwide. We identified 3000 of these machines and blocked them, and then the fun really started. We started a webpage and published lists of the attack sites and the number of attacks from each site, which really annoyed some people who organise the probes.

    Having had about 1100 attacks per day when we started the tempo was upped to 11000 per day three weeks later. It then dropped off back to 1000 per day and on the 7th April we had an instantaneous 40 fold increase to 40000 attacks for just one day. The bullet proof properties of our site withstood the onslaught. We then received emails saying that our site had been taken over, a fact we knew was false as we could inspect all activity in the log files. For the past two weeks the attack tempo has dropped to less than 500 per day, very few of which even make it past the first level of filtering.

    We now weekly publish details of the attackers and graph the attack tempo at


    Many site owners globally have requested copies of our statistics and the identities that we have resolved.

    We are now in the process of constructing a huge WHOIS database that allows us to reverse lookup from where the attacks are coming. This is showing up patterns of links between certain ISPs. We have about 250000 data points at present and look for situations where there seems to be a high level of coordination, especially in time and message content.

    For those interested in this subject, you want to research the story behind "dellpc.com".

    In short Dell Security division noted that a site had been registered called "dellpc.com". They approached the regulators in the USA claiming this name was close to their company identity and applied to have it transferred to their name. The registrant was not clearly identified except by a yahoo email address and did not oppose the transfer legally. When Dell started operating the domain, they found it receiving large emails that contained confidential corporate information from many important companies. It seems that this was a control node that had been designated in specially created viruses that had been inserted into the target companies computer systems, gathered data over a long period and sent the packed information to the control node.

    Dell went further and found the same registrant email address had been used on a number of similar sites which are also likely to be control nodes. The email address was unmanned and so it was not possible to find out who was the registrant. However they managed to find out that it was a specific lecturer in China as he gave the same email address when pressed for a current email address when registering for a conference. They now have published his biography together with photos of the person creating this network.

    We currently are trying to find the patterns from our data that might lead to the identities of control nodes.

    We have written some very clever programs for processing the large number of datapoints very quickly looking for patterns. From this experience, one can foresee a large demand for people with Mathematical degrees for developing search programs and finding patterns in data.

    Want more info such as a list of attacking servers?

    27 March 2013

    This newsletter is available in a PDF format as well at http://trolleyscan.com/newsl96.pdf

    1. Different operation frequencies allocated to RFID
    2. Server attack

    1. Different operation frequencies allocated to RFID
    The most important criteria to select in choosing an RFID system is its operating frequency. The choice of frequency determines the performance that can be expected from the system.

    The world is divided into three regions for frequency plans which are then accepted or modified by the individual countries in the region. The regions are - Europe & Africa, North & South America, and Asia(excl Russia) with Australia.

    The regions draw up the masterplans for the management of the radio spectrum and these are then adapted and accepted by the individual countries in those regions. This means that for major issues there are blocks of frequencies allocated in the different regions, such as for example cell phones. Minor applications, such as RFID, are fitted in by the individual countries between the big blocks and as a result there are nearly 177 different plans for RFID globally.

    Because different frequencies will give different performance, there are five groups of frequencies allocated for RFID by the individual countries. These are typically

    1. 125kHz
    2. 13.56Mhz
    3. approx 900MHz
    4. approx 2.45GHz
    5. approx 5.8Ghz

    There are two modes of sending energy through space, namely magnetic and electric fields. Magnetic systems use coils to couple the energy into space and these coils can be quite small, but operating range is short. Electric field use antenna systems that are usually operating wavelength related - for example half wave dipole.

    The wavelength is the speed of light divided by operating frequency. The wavelength at 100MHz is 3 meters, 900Mhz is 33cms, 2.45Ghz is 12cms, and 5.8Ghz is 5cms.

    The electric field antenna collects energy passing and its collecting area is proportional to the wavelength squared. So a 900 Mhz system with a 16cm antenna size collects 7 times the energy that a 2.45GHz system can collect or 33 times the amount of energy a 5.8GHz system will collect. This reduction in energy collection with frequency means that a 900 Mhz is almost the ideal RFID frequency for passive systems having consideration for antenna size and operating range. Lower frequencies would give more performance but would have much larger antenna systems.

    For passive systems (that is where the transponder extracts its operating power from the energising field), typical ranges for the different operating frequencies are - 125KHz (2 centimetres), 13.56Mhz (1 metre), 900MHz (10 metres), 2.45GHz(1.2 metres) and 5.8Ghz (25 centimetres).

    The 125Khz and 13.56MHz systems are magnetic coupled which allow them to operate in situations where electric field systems cannot operate, such as underwater, inside the bodies of humans and animals, and even inside blocks of metal. The 125khz transponder can be made very small, the most common being a coil 1 millimetre in diameter and 11 millimetres long.

    In 1990 when the staff of Trolley Scan were involved in the development of a transponder that could be used for the labelling of items in a supermarket trolley, 900MHz as a frequency was only available in a few parts of the globe with many countries preferring that development happened at 2.45GHz, a frequency that was already allocated to microwave ovens which had very poor frequency stability.

    After Supertag(tm) was developed and demonstrated in South Africa(1994), the interest globally in RFID took off and countries slowly realised that they needed to allocate a frequency for RFID in the 900MHz region in order for their countries to stay competitive. By 2013 virtually every country in the world has finally allocated part of the spectrum at 900Mhz for RFID.

    Trolley Scan have a technical paper explaining these choices which can be requested Interested? - Use this link to be sent the white paper.

    2. Server attacks
    This section relates to some observations that would be of interest to readers who operate internet servers and please skip if not of interest.

    For the past 16 years Trolley Scan have been serving information from a stand alone webserver running a linux operating system. The server supplies about 2.5 million documents per annum in the form of HTML, PDF and JPG files. In the whole 16 years, on only about five occasions has it stopped and needed a reboot. Two of these stoppages have happened in the past three months and as a result we have been investigating the cause. Usually nobody looks at logfiles as everything is running smoothly until there is a problem.

    Particularly with what has recently happened with attacks in South Korea in the past weeks, internet security is becoming an issue.

    We found that the reason the machine had stopped was due to simultaneous attacks from about 300 machines distributed all over the globe on our server at virtually the same instant. This overloaded a stack causing the machine to stop. What was interesting about the attack was the distribution of the attacking servers and their time coordination. We have since limited the number of child processes that can be started at any time and made the machine bullet proof.

    On further analysis of the historical logfiles, we found that our machine was being probed by very many servers continuously. This takes the form of sending the server an email to a fictitious user on our server to see if our machine would acknowledge that the user is UNKNOWN. Once again the probing is coming from no single source but is routed through 3000 different slave servers around the world, but particularly from Russia, Belarus, Kazakistan and Vietnam. We have recorded about 80 000 of these attempts over the past 4 weeks.

    Because we have the logfiles and are experts at data processing and analysis, we find so far that about 3000 slave servers are being used to do this probing. They are connected as all the probing messages are the same with just part of the destination address changing. What is interesting is the use of individual slave servers is kept to once or so per week so that unless you have a long data set you will not notice the pattern. One can find the more important machines in the probing as they often use multiple IP addresses from the same server or group of servers.

    We then started blocking the probing from the more noticeable servers by listing them in the access.db file. This sent them an ACCESS DENIED message and they immediately knew that we knew who they were. This brought upon us a major storm, like hitting a bee hive. Whereas when we started this we were getting 1000 probes a day, we are now getting 9000 a day but have identified and blocked 90% of all probes. However new slave servers are being added all the time and whereas initially almost all the attacks were from Russia and Belarus, now many parts of the Western World are also involved in the attacks. These attacks are coordinated as at times all is very quiet and then the messages start coming fast and furious from all parts for an hour or so and then stop.

    In the past when we have had attacks, there were a few machines and you could see a coordination that might be with many people in a club all agreeing to do something at some time. We tracked these and blocked them and weathered the storm.

    This time we are convinced that the slave servers have been infected with a virus that allows some controlling body to coordinate and route targeted messages on their command and receive the feedback without the owners knowing. As the slave servers are only occasionally used for these messages, the existence of the virus is undetected.

    This whole exercise has become a James Bond like scenario. This server is really unimportant in the commercial sense as it has no commercial value and is just a repository for documents - i.e. it is not a bank server and it does not hold confidential information. It is only operating at 1% usage, it has a lot of spare resources,is a long way from being overloaded and is bulletproof after we closed the last loophole. Every time we get sent a probe, it is collected and added to a database that allows us to reverse understand the attacking structure and to see our impact on the probing.

    At present we are blocking 2984 servers that have been involved in multiple attacks on our server in the past four weeks, but we suspect this number might grow to 10000 when some of the servers that have only been used once are reused - unless someone discovers the virus in the client servers.

    We have published on our website a list of the top 200 (by frequency of attack) of the 2516 attack servers that have been active over the past month. We can also send a list on request of the attack servers.

    Want more info such as a list of attacking servers?

    3. Product range
    Trolley Scan are a manufacturer of UHF RFID systems.

    Trolley Scan manufacture fixed readers, portable readers and RFID-radar systems (Real Time Locating systems that give accurate position information) as well as a variety of transponders for different applications. Transponders come in the form of passive transponders with operating ranges up to 20 metres and battery assisted transponders with an operating range up to 40 metres. Trolley Scan also combine some of these components into packages for end users which are supplied with the appropriate software. Typical applications are asset management, notebook tracking, equipment barriers, store control, sheep and cattle tracking, event logging and sports timing systems.

    Trolley Scan have been delivering their RFID solutions for the past 15 years and offer full support for all their equipment.

    4. Getting your own complete RFID/radar system
    You can order RFID systems or RFID-radar systems from Trolleyscan.com

    Trolley Scan provide small RFID reader systems which give new users the ability to evaluate UHF RFID and their applications without needing specialised skills.

    Trolley Scan provide a variety of easy starter systems for first time users who have an application that needs a solution. Typical packages are :

    • Standard UHF long range readers with antennas and 100 transponders
    • RFID-radar system comprising long range reader, antennas and a variety of different transponders.
    • RFID-asset tracking systems comprising portable reader, antenna and a variety of transponders with software.
    • RFID-notebook/laptop tracking system comprising reader, antennas, transponders and software In addition components such as readers and transponders are available
    These systems are already operating in 52 countries.

    To find out details of the systems and to order see http://trolleyscan.com/

    4 February 2013

    This newsletter is available in a PDF format as well at http://trolleyscan.com/newsl95.pdf

    1. Linking Android tablets to RFID readers

    1. Linking Android tablets to RFID readers
    Recently Trolley Scan were approached to deliver a solution by a refuse collection service which needed to monitor the exact location of their wheelie bins and provide information such as weight of refuse collected, exact location of the bin and time and date on an automated basis.

    The intention is to fit each of the wheelie bins (about 300 000) with a transponder in the lip of the bin, and have a reader on top of the compacting vehicle that would read the identity of the transponder as the contents of the bin were tipped into the compactor. A load cell would also be fitted on the lifting mechanism to measure the mass of the each bin as it is picked up and dropped off.

    Using a standard long range EcoTag RFID reader from Trolley Scan and standard EcoTag RFID transponders, the RFID part of the project is easy to implement.

    This is a data gathering application and an onboard computer is needed in each vehicle to determine the exact GPS position of the lift, the identity of the bin, the mass of the bin, the date and time and route number. All this information needs to be logged for future analysis and transferred to HQ either at the end of the route or via 3G during the route.

    The development of the Android based tablet has delivered some hardware that can drastically simplify the solution. The Android operating system connects modules inside tablets together. Typical modules that the operating system handles are GPS receivers, accelerometers, compass, WiFi, Bluetooth, 3G, USB ports, cameras, displays and keyboards. Due to mass production these devices have become very cheap costing between US$100 and US$200 for a 10 inch display.

    There is also a lot of recent development in programming languages for these devices allowing programs to be created that easily gather data from the sensors and save the information and generate reports.

    The negatives of using mass produced cheap tablets for a project that would have a long operating life are:

  • The production cycle of the tablets is short before new generations of equipment are released with newer operating systems which means problems with repair, spare parts and compatibility with software in future versions.
  • Currently the Android operating system is going through fast development with new versions being released frequently. The new versions do not seem to be compatible completely with the hardware of earlier versions. This means that often one will not be able to upgrade the operating system with existing hardware as developments happen.
  • The tablet itself is not necessarily rugged enough to cater with the operating environment inside a truck.
  • New modules for control by the Android operating system are being added all the time. At present the latest versions of Android can handle serial communications only via a specific RS232/USB adapter.
  • The advantages of using the cheap tablets are:

  • A complete package with an extensive range of sophisticated modules that are incorporated into the tablets, such as GPS sensors, WiFi, 3G.
  • It has a large display for man-machine interface.
  • It operates on low voltage using little power that makes it suitable for operating from the truck battery.
  • That programming languages have been developed for the android package to allow simple programming of the modules to easily extract the measurement data from the sensors.
  • Not all android tablets are the same as although they might have similar sensors, the physical packaging is often different - for example whether the antennas are internal to the tablet or an external antenna can be used.

    There seems to be a lot of potential for using cheap Android based tablets as data collection platforms in automated data collection projects where RFID systems are used. The version we have been using for development has an external GPS antenna which can be mounted on the roof of the compactor to accurately position the vehicle and the bin locations when being emptied.

    8 January 2013

    This newsletter is available in a PDF format as well at


    1. Development of Real Time Locating System based on video rather than radio

    1. Development of Real Time Locating System based on video rather than radio
    As regular readers will be aware, Trolley Scan design and manufacture leading edge RFID (radio identification) systems and RFID-radar systems (RTLS- real time locating systems) which are supplied to users in 52 countries. Trolley Scan have been delivering equipment and solutions for the past 15 years.

    The radio locating systems can offer millimeter accuracy but are limited in operating range practically at present to 40 meters. Because the radio locating systems share limited bandwidth for communication between all the transponders and the reader, the speed of movement at which all transponders will be tracked is limited in situations where many transponders are present.

    Based on work done in the past with video solutions, Trolley Scan have been developing a video based real time locating system that can track over longer distances than the radio based systems and can provide accurate position measurements for all targets in the zone. As it is a video solution, it needs the targets to be in the view of the cameras when measurements are being made.

    The system is able to accurately determine the range and bearing from the camera for multiple targets providing position and tracking data for all the targets.

    The next challenge is to extract identity information from each target so that it can follow many targets at the same time. Identity information is important so as not to confuse one target with another.

    Realtime video analysis of images from cameras is a computer processing intensive application. Any item appearing in an image is a collection of adjacent pixels and the computer needs to analyse all the relevant pixels to make a decision about the item.

    Colour is also a challenge as the camera detects the levels of energy of red, green and blue spectrum that are reflected off the target The actual amounts collected depend on many factors including the brightness of the illuminator (e.g the sun) at that time. The colour the camera sees is the ratio between these three values rather than the absolute values, meaning an item with a purple colour(for example) in shade will have very different values than the same item when it is in sunlight.

    At present the systems are under development but we see uses for this technology in the tracking of trolleys in superstores, airports and parking lots in malls, as well as players on a sports field. In some cases it should also address the problem of detecting trolleys being removed from the parking lots.

    The system is aimed at supplementing the radio based offerings from Trolley Scan, solutions that are already in use in more than 500 locations worldwide.

    2 October 2012

    This newsletter is available in a PDF format as well at


    1. Getting a very low cost transponder
    2. Long term product stability

    1. Getting a very low cost transponder.
    If you listen to market researchers and potential large scale users, there is a large demand for very cheap RFID transponders. Low cost transponders are a requirement for success in some markets such as food retail if each item has to be labelled. How low is low cost - is not defined and it is partly the uncertainty that has stopped any large scale production happening. In this section we identify the technical issues in the manufacture of transponders.

    In the 1990s Trolley Scan was asked to take part in a survey to predict the component costs of transponders over the next five years. What was interesting from that survey based on the collective knowledge of companies producing low cost passive transponders, was that there were three major component costs for low cost transponders - namely

    1. the electronic chip
    2. the antenna which needs to interact with an electric field wave that is 30 centimetres in length
    3. assembly costs to mount the chip on the antenna structure and apply protective packaging for handling.

    The consensus at that time was that each of these components would make up a third of costs of making a transponder and this is most probably still true today.

    1) The electronic chip
    The electronic chip is made in a semiconductor foundry that has been optimised to make chips as small and cheaply as possible. It uses processes that are aimed at mass manufacturing where a minimum manufacturing volume is typically 100 000 at a time.

    The developments that happened that allowed a single chip to become the workhorse for RFID were those developments in chip technology that allowed the integration of UHF diodes, analogue circuitry and digital circuitry all on a single chip with a single manufacturing process . When the staff of Trolley Scan were involved in the development of the first passive transponders in 1990, we had a separate digital chip, an analogue chip, external high speed diodes and external capacitors in each transponder. At that time the digital and analogue chips had to be made in separate foundries as the chemicals and processes used in the one process poisoned the other process. Developments in the 1990s saw these technologies being merged and the UHF diodes able to operate efficiently at 1GHz being incorporated into the chip.

    An understanding of the developments in chip manufacture in silicon foundries explains why the technology called "printed electronics" as a solution to costs in RFID is not going to be viable. In the "printed electronics" process the aim is to print the transistor structures on cheaper substrates than silicon, and not need the high tolerance printing processes needed for semiconductor foundries. RFID at UHF frequencies currently pushes the boundaries in a silicon foundry and there is little chance that the huge technical gap between the "printed electronics" version and the conventional silicon substrate technology will close sufficiently for it to be a viable and cost effective replacement.

    2) Antenna structures.
    The antenna converts the energy travelling through the air into an electrical signal that can interact with the integrated chip on the transponder. The antenna is interacting with an electric field wave that is about 30 centimetres long and so the antenna is large physically compared to the very small integrated circuit. The antenna is so designed to resonate at its operating frequency, in the same way that a tuning fork resonates with an audio signal at its design frequency. The conversion of the electric field wave to electrical energy means that current is flowing in the legs of the antenna and this means that the antenna has to be made of a material with good conductivity.

    The simplest way to make a viable antenna is to use a copper clad substrate that is usually used for making printed circuit boards. However cheaper solutions are required. This has led to various initiatives to print the antenna with cheaper materials. A carbon paste is the cheapest form of conducting paste as carbon is so plentiful. However it is difficult to connect the electrical terminals of the integrated circuit to the carbon paste. Another problem is that if the antenna is flexed, hairline cracks appear in the dried paste which impede the current flow needed for the antenna to operate.

    Some solutions to this problem have been to electroplate copper onto the conducting paste to form a continuous surface that can bend without breaking the current flow, while another has been to use a silver based ink that is then heated and sintered. This last method is expensive and has also had issues with disposal at the end of life particularly in the EU as the antennas are then treated as hazardous waste needing special; disposal methods. As one can see, particularly due to its size and manufacturing methods, the antenna itself is a large part of the costs of a transponder.

    3)Transponder assembly
    Before high volume RFID transponder assembly needs arose, the smartcard technology had developed and assembly machines had been devised to assemble large volumes of credit card sized smartcards. It was possible to adapt these machines to make RFID transponders and this meant that production of millions of transponders was available almost from the outset. These machines attach the integrated circuit to the antenna foil, and then encapsulate the whole structure in its plastic packaging, as well as programming and testing the devices. However these assembly machines are complex and expensive.

    If RFID is going to be used in retail, then very high assembly volumes are needed. The limit on machine size seems to be a volume of 100 million transponders per annum per machine, which equates to about 7 transponders per second. This is about the limit on movement via motors as the inertia at higher speeds becomes so great that the motors have to become very large. So far it seems that only one of these machines has been built, but the current demand for transponders does not seem to be sufficient to keep it in operation. To meet the needs of RFID for retail, about 1 million of these machines would be needed.

    Price reduction with volume Generally the larger the production volume, the lower the costs as benefits from economy of scale are realised. However it does not mean that there are no costs. Because of the very high volumes that would be needed if retail items were to be tagged which would need very low cost transponders, there are only a few companies in the world that have the manufacturing equipment and skills to run a very large scale production operation. Before these companies would become involved, the price of the transponders needs to be high enough so that these companies could make a profit on the large investment they would need to make to build high volume assembly equipment.

    One has to question if any of the companies involved in RFID transponder manufacture are driven by the desire to deliver very cheap transponders. RFID is such a pervasive solution that its success is not dependent on satisfying the Fast Moving Goods market for retail tagging. There are many applications that can afford a higher value transponder that can allow the manufacturers to make some profit. As the higher value markets saturate in the future, and as more companies gain experience in very high volume delivery, then possibly the retail market can be addressed.

    2. Long term product stability
    RFID systems are the data capture component of many computer systems. Usage starts out as small test pilot studies and then more equipment is ordered in the form of readers and transponders as the application grows. For many users, the expectation is that the new transponders bought will be exactly compatible with the installed readers they are currently using so that the application can grow seamlessly.

    Clients of Trolley Scan in 52 countries are assured that our new generation transponders will be compatible with previous generations that have been supplied over the past fourteen years. Newer solutions are always in development, but parts and compatible components are available for all equipment provided over the past fourteen years.

    27 August 2012

    1 Timing at the Olympics and the use of RFID
    2 Tracking the players and ball in a soccer game

    Timing at the Olympics and the use of RFID
    Most of the world (except the USA which had delayed transmissions) has watched in real time over the past couple of weeks the spectacuilar Olympic Games held in London. Thirty eight different sports were organised and viewers around the world could watch the success and failure of their athletes attempting to win the Olympic Champion status.

    Having been involved in the development of RFID systems for the past 22 years and before that having been a key player and developer of timing systems for motorsport in South Africa, our interest was in the technology changes that had occured in timing systems with time.

    The most impressive development of these games, must be in the dissemination of information to millions of viewers globally, who could monitor on a website the reaction time of each competitor, interim time measurements and the final result as it happened in real time. With all this information, one had to have a laptop linked to the internet in front of the big screen TV to have all these dimensions unfold simultaneously.

    Because of all this realtime information, one was aware when the timing was fully automated - such as measuring the reaction times to the starter signal - versus when other systems were been used such as for the crossing the finishing line. The finish line is generally measured using optical systems as RFID is too undefined to provide an accurate time measurement. Understandably when 8 athletes can finish a 100 meter dash with a time spread of about 0.3 of a second, any automated sensor system is going to be tested.

    The basic dimension in the design of an RFID system is the wavelength, which is a unit with a dimension of typically 30 centimeters. Antennas are used to focus the energy into beams, - similar to what the reflector on a torch does with a globe - but as soon as these beams hit hard objects, they scatter - like shining a torch in a house of mirrors - meaning it is almost impossible to clearly define the energy beam. In a practical situation this limits the suitability for RFID solutions where high timing accuracy is needed. RFID can be used. for the timing of events where one second resolution is acceptable.

    In situations where there are a limited number of competitors, for high resolution timing, an optical system is used. This has a camera mounted above the competitors looking across the finish line. The image is recorded on a Digital Video Recorder (DVR) which time stamps each frame of the picture. Immediately after the event the frames taken when the competitors cross the line are examined and the accurate time of each competitor determined. A major advantage of this method is that very long finish lines can be handled, such as for rowing events where the finish line is the width of the rowing pan. It is in the area of digital video recorders over the past couple of years where major advances have taken place, with images stored on large random access memories and then transferred to disk - instead of tapes. These machines have come down in price to about US$100 making them suitable for small eventsl. Obviously at the same time higher accuracy versions are becoming available with higher frame rates and definition to cater for the professional market.

    However at present the DVR approach needs a human interpretation which shows in the response time it takes for the results to appear on the website from when the race is finished.

    What was interesting in the track events at the Olympics, was that despite all the technology, there is still a "human spotter" sitting at the finish line observing the finish in case the electronic results need to be revised.

    Tracking the players and ball in a soccer game.
    Trolley Scan had been approached a couple of years before the Soccer World Cup 2010 in South Africa, to see if the RFID-radar could be adapted to track the ball and players during a match. Although the RFID-radar can locate an item with accuracy in its field of view, it has limitations on the speed of movement of the items due to overloading the communications channel between the transponders and reader.

    The tracking of the ball seems to have been a problem that has been plaquing FIFA especially in determining whether a ball has crossed the line in the goal mouth - in situations where the ball has an amount of spin and bounces out again.

    One possible solution being proposed is to use the Sony Hawk-Eye system used for cricket and tennis matches. However this is a very complex system and is limited to major matches. One of the founders of Trolley Scan had occasion to help the Hawk-Eye staff with a computer problem during a Cricket World Cup in South Africa a few years ago. He says there was so much equipment needed for the system that it took up a similar space to an Outside Broadcast van used by television companies.

    One would have thought that a simple solution for the goal mouth problem would be to mount four cameras into the goal posts at each end and record their images on one of these low cost DVR players, thus allowing a third ref to quickly replay the situation in cases where the referee is in doubt. However it seems that FIFA have a 5 second requirement for judgement which stops a simple solution.

    On tracking players, optics seems to be the best approach and having some software to automatically analyse the images from cameras, cameras that can record a large section of the field at one time. The problem arises when two players come close together and the software can then get confused as to which player left in which direction.

    Night vision cameras used in homes use LEDs for illumination that are not visible to the human eye, but fall within the response spectrum of the cameras. Making small LED flashers using these LEDs which could be attached to the players and made to flash out quickly an identity code that would not be seen by the human eye - but would be seen by the image detectors in the cameras, could dramatically simplify the problem of identifying the specific players when analysing large images of a large part of the field.. The software would need to detect which pixels are changing very fast in comparing frame to frame, and hence locate the individual players. This could also possibly be adapted to the Olympic situation of identifying atheletes automatically in photo finish equipment.

    20 July 2012

    Your latest copy of our regular newsletter
    keeping you up to date with developments.

    1 RFID for data collection or clever application
    2 Radar measurements under computer monitoring.

    RFID for data collection or clever application
    As a leading global supplier and designer of RFID systems, Trolley Scan frequently get asked to advise on suitable configurations for the implemention of RFID- data collection system.

    RFID systems are often the data capture components that form the front end of a computer system which implements some application.

    Due to the complexity of radio wave propogation which forms a critical part of RFID systems, often the sensing part of the RFID systems have minor imperfections that need to be taken out by logical processing of the data.

    An example of such is that due to the vectorial addition of multipath radio waves between the transponder and the reader,it is possible for an RFID tag to be in an "RF-hole" and its data missed by the reader. These holes are very small as they require all the geometry of the multipath waves to be so orientated to exactly cancel the main beam signal. A solution is to have some movement in the environment of the reader or for the reader and transponder to move relatively so that the multipath geometery no longer creates a perfect cancelation environment.

    We recently were asked to consider an RFID solution to check for the presence of bond certificates in a filing cabinet each day. The certificates have an RFID transponder attached to each certificate and the relevant bank needs to know that no certificates are missing each morning.

    One solution is to pass a portable RFID reader over each drawer of the filing cabinet and record all the ID numbers present on a USB memory stick, and then take this away for processing at a remote office.

    Another solution would be to base the system around our RFIDasset(tm) tracking package, where all the certificates and their location are kept in a database on a laptop that forms part of the RFID system. The reader is connected to the laptop via a Bluetooth interface that passes all the ID numbers to the laptop, which instantaneously is able to check off the presence of the individual certificates as they are read, to update their location if moved, and immediately report certificates that are missing. This means the operator is immediately aware of the problem and can double check to see that the certificate has not been misread, or find out from the staff the reason for the certificate not being in the correct place.

    Especially in asset tracking applications where there are a large number of items in the vicinity of the reader,a laptop computer attached to the reader becomes essential - as the reader reads tags far faster than can be absorbed by a human operator. (A Trolley Scan reader reads tags at up to 70 per second).

    Radar measurements under computer monitoring.
    RFID-radar(tm) is an RFID system that can measure very accurately the distance from a transponder to the reader, with millimeter precision at distances up to 40 meters. Because of its long term stability using the wavelength of the operating frequency as its measuring reference - the system has the ability to detect long term slight movement in structures such as bridges, dam walls, mine roofes, and buildings.

    One of the uses is to detect movement and sound an alarm to provide early warning of a potential failure.

    The radar makes thousands of measurements which are passed onto the computer. The computer needs to analyse the readings continuously to check that movement has not occured that is outside acceptable limits. However the program needs to use a type of fuzzy logic so that it does not trigger when the radio waves between the transponder and the reader are disturbed such as when a bird flies through the zone.

    16 April 2012

    Your latest copy of our regular newsletter
    keeping you up to date with developments.

    1 Marking yachts,boats,soft drink fridges, LDV canopies
    2 Camera developments
    3 The reality of a patent portfolio
    4 Product range

    Marking yachts, boats, soft drink fridges, LDV canopies
    As a manufacturer of RFID readers, transponders and solutions - the company gets approached by many companies in need of a solution to their problems.

    One of the recurring problems asked for a solutions is in the identification of fibreglass items to prove ownership. A typical request might relate to a fridge for softdrinks in a retail store where the fridge is owned by the soft drink company, and might be stolen at some time and then appear in another store. All identification marks have been removed from the fridge and although the softdrink company might suspect it is one of theirs, there is no way of proving the identity. A similar problem exists for mass produced items such as hobie cats, surf boards and canopies for LDVs.

    Trolley Scan produce a thin wire transponder that is a little thicker than a human hair, can be incorporated in the product during the moulding process, is passive with a very long operational life, and can be read with a reader up to 10 meters away providing a unique number.

    As the transponder is incorporated in the moulding, can be read at a long distance, and is very small - the thieves who are trying to remove all the identification tags cannot locate the transponder and it continues to provide a unique identification number for the life of the product.

    Camera developments
    In the last newsletter we discussed a remote security camera that can be set up in far away holiday homes, boats or places which need to be monitored but are far from normal human inhabitation or infrastructure.

    This was a new project we were testing to understand the pros and cons of such technology. The camera system is completely under the control of the owner thousands of miles away who can activate the camera, turn on heat sensing detection or night vision, receive photgraphs from the camera when an intruder is detected, or just send a snap shot on demand - all linked by the owners cell phone.

    After a couple of months of use from a test site 90 km from base, we can report that the technology is very reliable and cheap to operate, even in places that are very far from the normal infrastructure one has in residential areas.

    An associate in New Zealand has now started testing and developing a similar system based on the New Zealand infrastructure.

    Interested? - Use this link to be sent the brochure.


    The reality of a patent portfolio in RFID
    Recently while doing our annual financial statements we had to review our current patent portfolio which has 236 financial entries just for patents. Trolley Scan are one of the leaders in developing RFID over the past 17 years and have been at the forefront of many developments.

    In considering these filings some lessons come to mind that are worth sharing and we have prepared a white paper on the issues. Some points are:

    1) There is no such feature as global protection.

    2) Patents are basically a contract between the inventor and the country where it is filed. In exchange for making public the details of the invention, the country will provide protection for up to 20 years to specific aspects of the invention that are unique and have not been published before or patented before.

    3) The granted patent stops others making, using or selling just in the country where the patent is granted. Parties in any other country where the patent was not filed are free to make, use and sell the item and also have the advantage of the published patent providing the information on how to make the product.

    Interested? - Use this link to be sent the white paper.


    Product range
    Trolley Scan are a manufacturer of UHF RFID systems. They manufacture fixed readers, portable readers and radar systems as well as a variety of transponders for different applications. Trolley Scan also combine some of these components into packages for end users which are supplied with the appropriate software. Typical applications are asset management, notebook tracking, equipment barriers, store control event logging and sports timing systems.

    Getting your own complete RFID/radar system
    You can order RFID systems from Trolleyscan.com

    Trolley Scan provide small RFID reader systems which give new users the ability to evaluate UHF RFID and their applications without needing specialised skills. The systems comprise a reader, antennas and 100 transponders based on the EcoTag technology. The user just connects the reader to a computer and provides mains power to have a fully operational system.

    These systems are already operating in 50 countries.

    To find out details of the systems and to order see http://trolleyscan.com/isosys.html

    9 February 2012

    Your latest copy of our regular newsletter
    keeping you up to date with developments.

    1 New consolidated brochure on RFID
    2 New product query

    New consolidated brochure on RFID
    In Jan 1994 at a supermarket in Pretoria, South Africa about 300 million TV viewers via 650 TV stations saw a demonstration of a plastic supermarket trolley filled with 38 items being scanned automatically by passing it past a reader without the contents being unpacked. This demo was thanks to the invention of a RFID protocol called Supertag by a team led by Mike Marsh, the founder of Trolley Scan.
    Supertag protocol was owned by the South African Government and was later sold as part of a patent package for US$10 million.

    After leaving the government employ, Trolley Scan was later founded by Mike Marsh and focussed on developing other RFID protocols that were not related to Supertag. By 1998 the first of these advanced products were supplied to the global market and currently the company supplies users in 52 countries.

    Trolley Scan also developed the world's only RFID-radar system, a unique instrument that could measure accurately the distance to many passive and active transponders in its field of view with amazing precision, and virtually no difference in the bandwidth needed from conventional readers.

    Trolley Scan specialised in developing transponder technology that could operate at long ranges compared to anything available from other companies. A range of passive transponders were developed which eventually allow operational distances as far as 20 meters even when the transponder is attached to metal.

    More recently Trolley Scan have introduced some "systems in a box" solutions to applications such as asset tracking, notebook tracking, notebook barriers and instrument store management.

    Since the first products had been marketed in 1998, Trolley Scan have been detailing their developments in their brochure and updating the brochure as new developments were added.

    Trolley Scan have now rewritten the brochure to consolidate the product range, and to highlight how different reader technologies can be used with the same transponder technologies, and how different transponders used with the different readers will give different performance.

    Besides detailing the performance of the equipment and solutions on offer, the brochure covers numerous applications and then explains the radio frequency issues in using RFID systems, such as the methods of propagation, protocols, polarisation and multipath.

    In addition some 13 other documents are listed that are available from Trolley Scan explaining special issues that could be useful to users.

    The brochure is provided in pdf form, is 17 pages long and is worth reading if you have an interest in using RFID for applications

    Interested? - Use this link to be sent the brochure. mailto:info@trolleyscan.com?subject=Send_Trolley_Scan_brochure

    New product query
    This relates to a non-RFID problem. We are currently experimenting with a remote alarm, video link product for monitoring remote buildings - such as holiday homes in remote areas such as beaches or mountains. The product is like an advanced app for a cellphone, giving a picture of the distant room on demand, as well as monitoring the room continuously for movement and reporting to your cell phone with a picture if this occurs. The system has night vision and infrared movement detection. All the functions can be controlled remotely via the cellphone app. It is very cheap to operate and only requires that both the controlling cellphone and remote building are in cellphone coverage. It comes supplied in a box and you install it yourself.
    At present it is only available for locations in South Africa. This is a new development and if you want to be one of the early adopters contact Mike Marsh via link below.

    Interested? - Use this link to be sent the brochure.

    Getting your own complete RFID/radar system
    You can order RFID systems from Trolleyscan.com

    Trolley Scan provide small RFID reader systems which give new users the ability to evaluate UHF RFID and their applications without needing specialised skills. The systems comprise a reader, antennas and 100 transponders based on the EcoTag technology. The user just connects the reader to a computer and provides mains power to have a fully operational system.

    These systems are already operating in 50 countries.

    To find out details of the systems and to order see http://trolleyscan.com/isosys.html

    2 November 2011

    Your latest copy of our regular newsletter keeping you up to date with developments.

    1 Preventing the removal of computer equipment and valuable assets.
    2 How good is the radar range measuring ability.

    Trolley Scan (Pty) Ltd makes a variety of UHF RFID readers, Radars and transponders. These systems are the sensor components of computer systems for a variety of applications. In this newsletter we describe some of the application trends for which our systems are being ordered.

    Preventing the removal of computer equipment and valuable assets.
    RFID is a technology that is ideally suited for preventing and detecting the removal of valuable assets from a protected area.

    With the very sensitive passive transponders available from Trolley Scan, and the excellent read ranges available from its readers, an effective barrier can be created to record and alert when tagged items are being removed from a zone.

    For a long time Trolley Scan have been providing the Notetrack(tm) hardware and software package to control the flow of notebook computers in and out of office buildings,recording the authorised passage of the devices while alerting to the unauthorised removal of such items.

    At the request of clients, the hardware has now also been adapted to create alarm barriers to stop removal of items from uncontrolled exits and to channel the passage to monitored exits.

    Two examples of installations stand out, the one in a medical facility in the USA, and the other in a Central African training establishment for computer science.

    The readers are mounted at the the exit doors of the zone and continuously monitor the passageway. Should a tagged item enter the zone, it will immediately be detected and the readers emit a loud alarm signal to draw attention to the removal.

    In the case of the medical facility, equipment and even books may only be removed from the facility through the exit controlled by a guard. Other exits of the building have stand alone readers that make a loud noise if any of the tagged goods approach these exits, forcing the guarded exit to be used for moving of the goods.

    In the case of the schools in Africa, the readers are setup outside the computer room doors and should any equipment be removed, loud noises are made alerting passing staff.

    The reason this is successful is that the Trolley Scan transponders are passive, and are so sensitive that a laptop computer hidden from sight while up to 20 meters away can be detected. The reader does numerous checks on the signal it is receiving, such as data rates, duty cycle, checksums and many others to minimise the risk of false alarms. The readers have the ability to log the identity of any item that enters its zone. The readers use very low powers and provide uninterupted continuous monitoring, able to detect items passing at speeds up to 300kph.

    If interested send an email


    How good is the radar range measuring ability.
    The radar is a unique RFID based system that has the ability to measure accurately the radio path length the signal travels from the transponder to the reader. It has been designed not to use high interference techniques to make the measurement, such as might be used in military and airtraffic type situations - but rather low power, low interference techniques that causes virtually no interference, allowing many systems to operate in close proximity, and yet measuring accurately.

    To get accurate measurements, the radio path between the transponder and the reader should not be obstructed or else the radio path would have to travel an extra distance and this extended distance would be what is measured.

    Another factor to bear in mind is that the radio path is the vector sum of the direct path and all the reflected paths. The reflections come from any hard objects such as floors, walls cabinets etc. The reflected paths are likely to be different length to the direct path and hence can contaminate the direct path measurement. However energy in the reflected paths depends on the reflectivity of the reflector surface, and the extra distance the reflected signal has to travel, as energy in radio signals decreases by the inverse square of the distance.

    So the ideal situation for the best measurements would be that there is a strong unobstructed direct path, and that the reflected paths are much longer than the direct path meaning they are much weaker when they arrive at the reader.

    The radar exhibits millimeter sensitivity when operating in RELATIVE mode, able to resolve movements as small as 1 millimeter. Recent tests in a survey laboratory of a European University matching the system against other technologies used for precision measurement, has shown the basic accuracy of this method of measurement used in the RFID-radar, as well as what happens if the reflected paths are strong compared to the direct path.

    Because the RFID-radar measures the radio path length using physical parameters such as the operating frequency wavelength, precision is constant over the full range, from 40 meters to as close as a couple of meters.

    To find out details of the system see http://rfid-radar.com/

    31 May 2011

    1 Tracking of notebooks
    2 Timing of sports events
    3 Locating buried services.
    4 Measurement of movement of structures
    5 Measurement of power lines

    Trolley Scan (Pty) Ltd makes a variety of UHF RFID readers, Radars and transponders. These systems are the sensor components of computer systems for a variety of applications. In this newsletter we describe some of the application trends for which our systems are being ordered.

    Tracking of notebooks
    There is a lot of tender activity from large organisations wanting to track the movement of their notebook computers from their premises. Trolley Scan UHF RFID systems are being requested as the sensor components of some of these systems.

    Trolley Scan provide very sensitive passive transponders that can be attached to the notebook and can be read by a fixed reader up to 20 meters away. The owner also carries a credit card sized ID transponder which is read at the same time by the fixed reader. The software in the system matches the notebook to the ID badge and records the passage. If a notebook is detected without the linked ID badge, a warning is given to the guard at the exit.

    Trolley Scan provide the hardware and software for a single exit in their "system in a box" solution.

    They have also provided a software update that allowed seven exits to be controlled from one central point.

    To monitor notebooks, the physical situation has to allow limited numbers of exit points from the building so that notebooks and their users have to pass within range of a fixed reader.

    The other fact of life is that the transponder on the notebook has to be attached to the outside of the notebook. The construction of the notebook computer is such that the case forms a "Faraday cage" which prevents the radio signals generated on the inside of the notebook escaping to interfere with outside radio signals. More info on the website under Notetrack(tm)

    Timing of sports events
    Numerous organisations globally use the Trolley Scan readers and transponders for the timing of low key sports events. Although the systems can handle multiple transponders passing at speeds up to 300kph, they are not suitable for timing high precision events such as Formula One, but are very suitable for fun runs, MotoX and mountain bike events.

    Usually an enthusiast involved in the sport has a laptop computer and wants to write a computer program to do the timing and present the results. This starts off with manual capture on the keyboard and as the club grows and the number of competitors increase, a stage is reached where the club wants to add an RFID sensor system to automate the data capture.

    The Trolley Scan system is often chosen as it is easy to adapt to computer programs, it is relatively cheap, it can handle high speeds, it can operate from batteries and is reliable.

    Our largest installation to-date is for a club with 600 competitors. The one thing to realise with RFID is that the timing-line is the edge of the energy field radiated from the energising antenna, which is different from the straight line of the conventional finish line. This means that there can be a slight timing difference between a system based on RFID only as compared to a photo-finish. If a photo-beam is linked to the RFID system and the software adapted, then an accurate timing system can be built that will be comparable with the photo-finish timing systems.

    Locating buried services.
    In many countries telecom companies are digging up the roads to install fibreoptic based backbone systems. These are then being expanded to provide fibre optic connections to the individual homes. The acceptance of these services by the public varies and many of the connection points are left buried and unconnected until the service is requested by the individual. At that time the service provider has to locate the connection point without digging up the roads again.

    Burying one of Trolley Scan's very sensitive RFID transponders with the connection point allows the exact location of the connection point be identified using a portable reader as well as the exact ID number of the point.

    The Trolley Scan transponders are very sensitive, passive and can lie dormant under the surface for many years without degrading.

    There are some issues to consider. The depth of penetration of UHF RFID signals into the ground is a function of the water content of the soil at that time. Hence if you are in floods or if the water is pooled over the connector, UHF RFID signals are not going to penetrate the surface. Hence the location of the connectors needs to be scheduled when water is not pooling over the connection point.

    Measurement of movement of structures
    Trolley Scan also provide a unique system called an RFID-radar. This system measures the distance radio signals travel from the transponder to the reader and can give the 2D location simultaneously of a number of transponders up to distances of 40 meters. Despite using a similar narrow bandwidth as is used by our RFID readers, the system is able to monitor movements quickly with the precision of millimeters even for transponders as far as 40 meters away.

    The precision of the system, the ability to monitor up to 50 transponders simultaneously, the relative low cost, and the ability to move the reader from site to site to detect long term movement of structures, has meant that companies from a number of countries are using the system to detect movement in structures such as dam walls, bridges, buildings and tunnels. The system is suitable for permanent installation and continuous monitoring at a remote location in order to have an early detection of potential failures.

    Measurement of power lines
    Power lines carry the electricity from the power stations to the consumers. These structures are becoming more loaded as the demand for electricity increases, as the systems age and parallel lines suffer temporary failure, and as resistance from the public increases to allowing new lines to be built in their vicinity.

    The current flowing in the copper wires together with the resistance of the copper wire causes losses which cause local heating of the wires which causes expansion of the conductors and hence sagging of the lines. Additional current due to a failure of a parrallel route causes additional losses and hence more sagging. When too much sagging occurs there is potential for a dangerous situation to develops or a failure if they touch the ground.

    RFID-radar has the unique ability to remotely monitor the amount of sagging. Attaching a passive long range transponder permanently to the power conductors of the power line, allow the RFID-radar to measure the height of the transponders/conductors remotely to monitor the sagging. The advantage of RFID over other systems is that they transponder is electrically isolated from all the other conductors and can be measured using radio waves without influencing the integrity of the power lines.

    22 September 2010

    1 Public municipality instals multi-reader notetrack system
    2 Health and safety access control
    3 Supply of parts
    4 The new ID field - video data
    5 How are the cows?

    Public municipality instals multi-reader notetrack system
    In the past the Notetrack(tm) system supplied by Trolley Scan in a "system in a box" form has been aimed at small installations where a guard point at an exit would be informed if a notebook computer enters the exit zone without the matching authorisation. To do this the RFID reader equipment is connected directly to the computer at the guard's workstation and provides the necessary protection.

    Trolley Scan have been asked to expand the system to cater for multiple exits at municipal offices, with the system being controlled via the security office for all exits.

    Modifying the reader equipment and expanding the software solved the problems and allows for seven exits to be controlled from a single point monitoring all laptop and notebook computers leaving the premises. Should an alarm condition occur, the staff of the security office are informed as well as an alarm sounding at the specific exit point.

    The system has been supplied and can now be offered to others as a "system in a bigger box"

    Health and safety access control
    Particularly on industrial sites where dangerous machinery is operated, the requirement to limit certain members of staff from entering the area around the machines has developed as part of Health and Safety regulations. This approach limits people who are not aware of the dangers of the machinery or environment from coming into the areas without due escort. On large industrial sites, many of these areas often exist.

    Trolley Scan have supplied to our partner the systems for installation at a large industrial site that protects ten such zones from casual access.

    Each staff member carries an RFID card that is read by readers at the entry points to the zones. In a database are recorded all the restricted zones to which this person holds the qualifications to enter.

    All entries are logged in the Security Control Room and should a person not be qualified to enter a zone, then an alarm is sounded at the reader when the person enters the zone as well as in the Security Control room.

    With Trolley Scan's long read range abilities, cards are read at a distance and the system operates unobtrusively without requiring users to continually present their cards.

    Trolley Scan provided the hardware and provided the software to control the system from a computer in the Security Control room.

    Supply of parts
    For the first time in 15 years, Trolley Scan actually ran out of parts due to the large volume of orders placed. Normally this is not a problem as orders for restocking are placed in good time usually with lead times of up to two months. However the manufacturers of components seem to cut back drastically in their capacity and their deliveries have been slipping out to 4 months. Even yesterday we received an email from a major manufacturer that they were slipping the delivery by a further week.

    Luckily our critical parts are now back in-stock and deliveries are flowing again.

    The new ID field - video data
    There is a lot of similarity in applications between RFID and extracting identity and position information from video data from a CCTV camera. Both of them provide information that can be used as identity information to a computer program for processing.

    Video data however is very difficult to use for most computer systems. The problem is that computers are very slow devices compared to video sensors. A video picture has typically 200 000 data points in each picture and these arrive 50 times per second. Also the organisation of the data stream is such that two pixels that are next to each other in the image are often far removed in the data from the device. Computers like to work with data that is very close by and the problem is contained.

    Trolley Scan have developed a video processor unit for attaching to any slow computer and allows a program to simply analyse the images and save images of interest. Initially this is being used in perimeter detection where only the specific pixels of interest are processed, but later the same hardware can be used in processing fast moving images, such as tracking the positions of players in a soccer game.

    Our video processor is a cheap unit with software and is very suitable for those who want to make a DIY CCTV perimeter monitoring system using an old computer or a computer that is mostly switched off at home.

    More information can be found at http://trolleyscan.com/videorec.html

    How are the cows?
    For those of you who wanted data on the Cowtrack(tm) system, you will have to be a little more patient. We have been implementing design changes to improve the accuracy of the system in situations where there is a large variation in the signal, such as when a cow is a few meters away versus many kilometers away. This is one of the projects that has been held up by the parts supply issue and we are waiting for one of the overseas manufacturers of parts to catch up with their deliveries. The good news is the parts will be very fresh when they arrives!!

    28 April 2010

    1) New development - EcoScan Equipment store monitoring system
    2) Long range location system

    EcoScan Equipment store monitoring system
    Trolley Scan have developed the EcoScan(tm) Store control system which is a system of RFID hardware and software for monitoring the movement of equipment in and out of an equipment store. This is a "system in a box" approach where the buyer can instal the system themselves. Just add a computer and you have a working system.

    Many manufacturing companies keep specialised equipment and instruments in a special store which allows the equipment to be used by many users when their need dictates. For example the equipment might be power tools, specialised spanners, calibration standards etc. The equipment is used periodically, is fetched from the store when needed, and returned when finished. Tracking when the equipment is taken from the store, by whom - and when it is returned when the task is completed is often haphazard. The Trolley Scan EcoScan(tm) Store control system puts order into the process and provides a simple record.

    The system involves a fixed reader at the doorway to the store connected to a computer, transponders attached to the items, an ID card carried in the users pocket, and a software package to manage the whole process automatically and seamlessly.

    Trolley Scan have developed a starter kit to allow anyone to easily implement tha system in their equipment store. It can also link to the RFIDasset(tm) tracking system for updating asset registers.

    Long range location system
    In the past RFID systems have been short range devices, initially with ranges in centimeters and more recently in tens of meters. Trolley Scan have been offering passive transponders recently with ranges up to 23 meters when attached to metal, and a RFID-radar system with accurate range measurement ability of millimeters and operating ranges of up to 40 meters.

    Over the fifteen years that Trolley Scan have been supplying equipment to our clients in 50 countries, they have frequently been asked to solve problems needing a lot more range than they could offer.

    Over the past few months they have been working on a long range version of Real Time Locating systems, where ranges are measured in kilometers and could be extended further.

    The type of problem this longer range version would need to address are the tracking and recovery of supermarket trolleys from the parking lots of a superstore, the location and recovery of airport luggage trolleys and the tracking of cows in pastures. Other problems have been the tracking of pleasure boats sailing from a harbour, tracking fishing boats in the sea off the coasts, tracking golf carts on a golf course and similar problems.

    To get the longer range Trolley Scan have had to change the operating frequency from their other products and develop a small and lightweight transponder that can be made cheaply and even carried on the ear of a cow. Unfortunately the new system transponders have to use battery power as these ranges are beyond that of passive technology meaning the requirement to use as small a battery as possible but still get a long operating life.

    The system comprises transponders attached to the items being tracked and a reader station where measurements are made and location determined. Radio waves do not like to travel through hard objects and so it is necessary to have the reader stations at high points where they can get a line of sight to the transponders. The higher the reader can be placed above the ground the longer the operating range. A chain of readers at different locations can be used so that the transponders are in touch with those closest to their location as they move. The readers are linked back to the base via a datalink so that plotting and management of the facility can be done from the comfort of an office.

    There are other tracking systems around using complex technology like GPS etc, but the location data still needs to be communicated which adds further complexity and battery power. In the new Trolley Scan system the aim is to provide a very cheap method of position location with minimal infrastructure and yet very reliable.

    The system is suited for slow moving items like boats and cows and is not going to work for high speed movement like tracking a soccer ball on the field.

    This product is being sold under the name Cowtrack(tm)

    21 February 2010

    Expanding the abilities of RFID
    RFID systems are sensor systems that are data capture devices for computer networks. Generally users would want applications solved and would use RFID systems to capture the data and software written by software companies to organise the data and provide a solution for the application.

    Users of Trolley Scan equipment and readers of this newsletter will know that Trolley Scan provide a range of leading edge RFID systems. Trolley Scan make fixed readers that can read transponders up to 13 meters away, 800 in a zone at a time, 70 per second and up to 300 kph. Trolley Scan also make portable readers that can be used in logistics and asset tracking applications with a 10 meter range. Trolley Scan are the only manufacturers of RFID systems that give precise location of the transponders in a zone up to 40 meters deep, a product that is known worldwide as RFID-radar. Trolley Scan also make a variety of transponders compatible with their readers, from thin wire laundry tags, to very efficient credit card sized tags and even battery assisted tags.

    Trolley Scan are in regular communication with some 4500 companies on a monthly basis. Many of these people have highlighted the need for a technology to provide affordable location information over much larger areas to find assets, such as supermarket trolleys in a large car park, airport luggage trolleys, golf carts on a golf course, farm implements on a farm, fishing boats and yachts sailing from a club or a harbour. The issue has been to drastically increase the operating range without using increased bandwidth or afford ability. The system is great for positioning static or near static items that are moving and is no use for tracking soccer players on a pitch.

    The system is very different from RFID-radar, fits different operating situations, and complements the range of products offered by Trolley Scan.

    Over the past three months the prototype has been under test and currently its parts are being industrialised. We will shortly be announcing the addition to Trolley Scan's product range

    4 December 2009

    1) New SURVEY mode added to RFID-radar capabilities
    2) New RFID concept testing

    New SURVEY mode added to RFID-radar capabilities
    Readers of these newsletters will be aware that the RFID-radar equipment, designed and supplied by Trolley Scan (Pty) Ltd, can identify and measure the position of many tags in the reader zone simultaneously. It also has features that can continuously monitor the length of the radio path between these transponders and the reader, and that the system can detect changes in distance as small as 1 millimetre at distances up to 40 metres. This is useful for continually monitoring the movement of structures with wind and water loading, or movement of bridges with different traffic loading.

    Trolley Scan have now added a new SURVEY mode to the system to allow the accurate long term measurement of structures with millimetre precision. The new mode allows the reader equipment to be removed from the site for long periods and later repositioned to measure the movement of the structures in the intervening period. This allows movement of structures like retaining walls in landslide prone areas, swelling of dam walls with different water levels and time, movement of walls and roofs in tunnels, and similar applications.

    Transponders are attached to the structure being monitored and the reader setup at a distance so that it can measure the radio path length to all the transponders. These measurements are saved. The reader equipment is then moved to other sites or storage. When the movement is to be checked, the reader is repositioned, a new set of measurements to the individual transponders recorded, and movement calculated.

    The new SURVEY mode is a low cost application of measuring technology allowing potentially dangerous situations to be monitored without the need of highly skilled operators or expensive equipment such as laser range measuring equipment.

    A brochure on the new system can be downloaded at www.rfid-radar.com

    New RFID concept testing
    In our past newsletter we announced that Trolley Scan were in the process of developing a new concept in RFID that would complement our existing product range of RFID readers, RFID-radar systems and transponders.

    The new concept will provide solutions for many users who in the past were limited by what RFID could do for their problems.

    Since the last newsletter our prototype system has been involved in field trials with very encouraging results.

    Trolley Scan are currently developing the commercial version from the prototype designs.

    Watch this newsletter for further developments.

    25 September 2009

    Major new RFID development - a new concept comes to life

    Major new RFID development- a new concept comes to life
    During the past two months the developers at Trolley Scan have been hard at work bringing to life a new concept in RFID technology. This started out as a radical idea and has now grown into a practical sensor system that will meet many of the needs of clients whom contact Trolley Scan daily wanting the boundaries pushed on what is currently achievable with RFID.

    RFID is a rapidly developing technology where major push backs of barriers are expected. In 1990 transponder ranges for passive systems were 0.5 to 1 meter, while today 24 meters with a 100-year-life passive transponder attached to metal is an off the shelf item. In 1990 range was never an issue as the tag was always 0,5 meters in front of reader, while now Trolley Scan can offer a RFID-radar system using the same passive transponders that can locate tags to millimeter accuracy up to 40 meters away.

    There have also been many other developments that have been announced in the past, such as reading up to 800 items in a zone at a time at read rates of up to 70 items a second, smaller antenna systems, portable RFID systems, lower operating powers, lower interference footprints, operating maximum speeds of 300kph, and the list goes on.

    To bring the new idea to reality, Trolley Scan have had to stretch the performance achievable from transistor circuits, develop new radio frequency designs, develop antenna systems, develop advanced signal processing software, develop better analysis systems, better control software, improve measuring techniques, and make hundreds of tests. On 24th September 2009 we managed to carry out our first full scale test of the concept which showed that this system would soon be suitable for use by the market.

    Presently Trolley Scan provide advanced RFID reader systems, RFID-radar systems, and a variety of transponder systems to users in 50 countries. The new concept will compliment the existing product range providing solutions for many users who in the past were limited by what RFID could do for their problems.

    The new concept still needs to be packaged into an off the shelf form with enduser software so it too can be provided to users as a "system in a box".

    Watch this newsletter for further developments.

    23 July 2009

    1) Take Inventory!! - Getting productivity from RFID and software

    Take Inventory!! - Getting productivity from RFID and software
    RFID is a data collection technology. With UHF systems like those from Trolley Scan, up to 800 items in a zone can be read at a time at read rates of 70 per second and distances up to 20 metres. This data rate exceeds the ability of humans to monitor the information and so RFID systems are connected to computers for capturing and processing the data.

    Particularly if the reader can be moved around and yet still remain connected to the computer via an interface, a very powerful and effective solution for an application is viable.

    We recently have been asked to provide a solution to companies wanting paper files tracked in an insurance type company, wine bottles tracked in a wine store in a restaurant, human body parts tracked in a medical teaching facility, new cars from a motor manufacturer in a pre-delivery holding lot, and fixed assets tracked in a large engineering facility. The requirements are actually very similar. The requester wants to know that the assets are in their premises/store and the requester wants to be able to find a particular item when they need it.

    In the simplistic approach, an RFID reader could continuously monitor all the items once per second and report the location. However this would require a lot of readers if the premises are large and would be expensive.

    The other day I phoned a supplier to get a particular type of paint. While on the phone he accessed his computer database and could tell me it was in stock and the price. He did not need to go into the warehouse to check to answer my question, as he was confident the database in his computer was correct. There is nothing clever about this approach as it is used in millions of businesses daily - but it shows that the query information should come from databases - and it should be the role of the RFID to just keep the database up to date should the organisation have a management breakdown.

    RFID systems are very good in reading thousands of tags at the same time and telling the operator if a specific tag is present in the reading zone. Using RFID, the user can either capture the entire contents of the store/drawer/file case, or tell if a specific item is in the drawer. In both cases they read all the tags very quickly, and it is the processing computer that identifies the specific tag and informs the operator that the tag is currently in the reader beam.

    The important item in a modern RFID/database system is the database. The database links the IDdata in the tag to the physical description of the item (and other details), as well as provide a place to record its current geographical position. Then using a portable RFID reader to scan all the tags in the filing cabinet drawer/container in fridge/room in building all the items that are in that specific location can be automatically designated for their geographical position in the database. This is repeated for all drawers/containers/rooms to set the correct current positions of all items.

    When items are withdrawn/added to the storage containers the database should be updated either manually or with RFID. The database at all times reflects the best knowledge about the current positions of all items.

    This database can be accessed by all users of the items and in almost all cases it will be insync with reality. There obviously will be times when the database and reality are no longer in sync or where a particular item has been misplaced, at which time another scan with the RFID reader can update the database or find a specific missing item.

    The advantage of this approach is that

  • information about the current location of items is widely available to all users of the database,
  • there is a level of order in the movement of items rather than chaos,
  • that very little RFID hardware is needed to operate the system efficiently even if over a large geographical area
  • that any item that has been misplaced from the organised system can be found with the RFID scanner
  • that even in the event of a catastrophic failure the database with current positions can be speedily rebuilt
  • that for audit purposes the RFID scanner can quickly verify that all the assets are still present without having to handle each item.
  • This type of approach to asset management is the result of having UHF RFID portable systems that offer long reading range, able to process large number of items in a reading zone at a time, have fast reading rates, and very sensitive RFID tags that can be read even when shielded by other items in the container.

    Trolley Scan offer an RFIDasset(tm) starter kit comprising tags, portable reader, blue tooth data link and software.

    More info can be found at the website www.trolleyscan.com or

    send an email

    send an email

    26th May 2009

    Leap in the performance of UHF passive transponder technology

    In this newsletter we detail another major performance achievement for passive UHF RFID transponders.

    Another leap in the performance of UHF passive transponder technology
    The distance is 25.6 metres and the transponder is attached to a metal item!!.

    This is the functional distance from the reader, as measured with the RFID-radar, of the new generation passive UHF transponder developed by Trolley Scan. UHF transponders attached to metal items are another problem situation addressed by the Trolley Scan development.

    Passive transponders do not have their own onboard source of power but extract operating power from the energising field of the reader.

    Previously, the maximum range with passive transponders with Trolley Scan readers was 13 metres.

    The impressive performance comes from the combination of a new integrated circuit specially made for Trolley Scan and from Trolley Scan's spectacular RF antenna developments for transponders.

    The new transponder has been specifically designed to be used with tracking laptop computers and office equipment, but also finds use in tagging metal items.

    The actual operating range achieved with the new transponder is not important. Trolley Scan have for a long time supplied battery assisted transponders that had a 40 metre range, and this improvement just means lower costs, increasing operating life from a few months to 100 years, and providing simpler technology for medium range situations.

    What the development does signify is how passive types of transponders are moving into applications that in the past could only be satisfied with battery assisted and active type transponders. It also allows progress on the development of low power technology to be accurately measured.

    By way of an explanation for those technically interested.
    The staff at Trolley Scan were involved in the first developments of UHF transponders for retail applications, namely the development of Supertag in 1990 in Pretoria, South Africa.
    At that time we aimed to build a single chip transponder for use in tagging items in a grocery trolley. Then semiconductor technology was at such a stage of development that there were analogue type devices which could handle RF components, and a separate type of technology was in use for digital circuitry for data handling. Hence we ended up with two chips on each transponder. About ten years later single chip devices were practical that had both the RF and the digital circuitry on a single device and single chip transponders became available.

    The transponders get their power from the energising field and to visualise the power distribution back in 1990, we made a number of small dipoles with light emitting diodes. Attaching these to the wall of the office and aiming the energising antennas at the wall from about 3 metres away, together with a fair size RF power generator, we could get the LEDs to glow if they were in the main beam and hence see the power distribution. Those devices needed about 54 milliwatts of power in the collecting area and had an operating range of about three metres with the transmitters and antennas we then used. The two chip transponders needed similar power.

    Since January 2004, Trolley Scan have been supplying 200uW versions of transponders, that is a 250 times improvement on the originals. We now have a new transponder which is also passive, is attached to metal items, and uses just 40 microwatts (uW) of power, that is 1350 times less power than the originals.

    This dramatic improvement over time, has meant greatly increased range for operation. It also has led to reduced energising power being needed from the reader, which means smaller RF amplifiers and the ability to use lower gain antennas which can spread the power over a wider angle increasing the area of coverage. The lower power needs of the new transponders also means that portable readers which can operate on batteries for a reasonable time and yet give a 10 metre read range are practical.

    Trolley Scan make UHF RFID fixed readers. UHF portable readers, UHF RFID-radar systems and a range of transponders for different packaging requirements. The new transponder technology is compatible with all the reader products made by Trolley Scan and with all the earlier ranges of transponders.

    24 April 2009

    1) Development directions for RFID

    Development directions for RFID
    In 2010 we here in South Africa will be hosting one of the globe's largest media and sporting events, namely the 2010 FIFA Soccer World Cup. Technology is going to cause an interesting split in viewers of this event. Some will want high bandwidth communications so that they can watch it on a 5 centimetre cell phone screen, while others will want 42 inch screens with high definition satellite feeds. The people watching on the cellphones are never really going to know what is going on in the game, but they are going to feel good about their application of technology.

    In the same way, RFID is a technology that is suitable for some applications and not necessarily for others. RFID is a rapidly developing technology that is steadily finding its niche applications and it might be worthwhile to consider the directions of some of those developments.

    RFID is a data capture technology that allows the identity of items that are in close proximity to a reader to be communicated to a computer system for processing. It can read large numbers of identities in a zone, very quickly, accurately, and within radio distance of the reader. It can be made at very low cost which means that relatively inexpensive items can be cost effectively labelled. What makes it useful is when it is combined with the correct software application to manage these large amounts of data and generate simple, human compatible outputs.

    The ultimate application of RFID is in reading the contents of a supermarket trolley, an application that was first demonstrated in South Africa in 1994. Although technically RFID can meet this challenge, it is not a commercially viable application due to the high cost of the transponders.

    There are a number of new developments happening that are improving RFID.

    1)Lower power RF performance.
    As passive transponders operate on energy received in the form of radio power, and as this radio energy that is available degrades with distance, major developments are taking place to produce lower powered transponders. These developments focus both on the radio properties and the intrinsic operating powers of the transponders. The lower power developments mean that passive transponders are replacing the former active types of transponders due to their increased range and lower costs. The lower power devices also result in the viability of portable reader systems with good operating ranges and good battery life.

    2)Range information
    When transponder operating powers were high and ranges short, location of the transponders was not an issue as they were immediately in front of the reader. As ranges increased beyond 6 metres and approach up to 40 metres, it has become important to know the position of the transponder relative to the reader so that the item can be easily physically identified. These longer ranges mean that a single reader can now monitor an area that in the past had to be covered by many readers. This has resulted in Real Time Locating Systems (such as RFID-radar) moving into the RFID-reader market space.

    3)Manufacturing cost
    For many years there has been a wish to have very low cost transponders, especially by high volume users. Those who understand the issues realise that there is a floor to the pricing and very low cost parts are not going to be a reality. There are three major cost centres to making transponders, namely the chip, the antenna and the assembly/packaging. In a survey we were part of a few years ago, it became apparent from participants that roughly one third of the costs can be assigned to each of these centres.

    4)Smaller antenna size
    To transfer energy by radio means, antennas are used to convert electrical signals to radio waves and vice versa. The size of these antennas are dependant on the operating frequency of the systems. Breaking the relationship of size/frequency generally results in a drastic reduction in effectiveness. Users would like antenna systems that are as small as possible but still effective.

    5)RF interference
    As RFID systems become more popular it is going to be more likely that one RFID reader will interfere with another RFID reader close by as many users try to share the same allocated radio spectrum. Attention is going to have to be given to the interference profile of the different types of protocols. At present there are low interference tag-talks-first and high interference reader-talks-first protocols.

    6)Increasing dynamic range
    RFID readers are amazing pieces of technology, detecting very weak signals from transponders while in the presence of relatively strong energising signals. As the operating range of systems has been increasing, the readers have had to simultaneously detect transmissions from transponders that are very close to the reader and those that are very far. This has to be done without changing the amplification of the readers so as not to miss any transmission.

    7)New protocols
    Presently the simple protocols in use require each transponders to have a unique identity to be identified correctly. There are available more advanced RFID protocols that allow many transponders with the same identity number to be accurately identified and counted, protocols where the uniqueness of the data is not used for identity. In future systems where only product numbers are needed, these advanced protocols will be needed.

    24 February 2009

    1) Interesting projects
    2) New developments in passive transponder technology

    Interesting projects
    RFID systems are the data capture components of some bigger productivity/management system. When a transponder comes close to a reader, the reader is able to identify the transponder and pass its identity on to a computer system for processing of the event. Most RFID systems only work over very short range, but the advanced technology available from Trolley Scan allow operating ranges up to 40 meters, 800 tags in a zone at a time, read rates up to 70 per second and speeds up to 300kph - as well as Rfid-radar systems that can measure the physical position of tags in the zone to millimeter accuracy.

    With such versatile performance for the data capture components of a system, RFID systems have become a basic building block of many IT systems that are used for measuring performance, management, security or the monitoring of assets.

    The ability of long range UHF RFID to be able to detect passing laptop computers even when they are being carried in a case, has resulted in many projects being initiated to protect companies from losing their laptop computers due to theft. The ability to match computers to their owners when passing through security checkpoints allow quick processing of staff and visitors at exit points without the loss of security.

    Recently Trolley Scan have provided systems to detect underground services such as fibre optic cables for telecom providers. The cables are buried when they are laid and need to be located when repairs are needed. By burying cheap passive transponders at the time of laying with the cables, the exact position of the cable can be determined when repairs are needed. The UHF energy from the portable reader penetrates the ground to power up the transponder which then emits its identity. The use of this technology is complicated due to the absorption of energy by the soils in different moisture conditions.

    Because of the ability to detect transponders at speed, Trolley Scan systems are widely used in timing systems for sports events. This allows enthusiasts to build a low cost timing system by just adding a computer and some software. Recently we have provided a 1000 transponder system for the timing of mountain bikes - add to the portfolio of systems in use worldwide.

    RFID-radar can measure the position of multiple transponders physically relative to the reader. Applications are being developed to use these features to assist disabled people, particularly those who are vision impaired.

    RFID has invaded the arts with RFID-radar systems which are being used as sensor systems to allow patrons to interact with art displays in galleries. By sensing transponders on the body, the controlling computer can change the electronic displays that the patron is observing by movements of the body of the patron.

    New developments in passive transponder technology
    One of the key parameters to measure the technological progress of RFID, is to monitor the amount of RF energy needed to operate a passive transponder. The transponder collects its energy from the energising field of the reader, and when the amount collected reaches the operating requirement, the transponder is powered-up and can function properly.

    The energy density from the reader decreases as the inverse square of the distance - that is every doubling of distance requires four times as much power, or a tag 10 meters from a reader only receives 1% of the power density of a tag 1 meter away. Hence by reducing the amount of energy needed to operate a transponder, operating ranges can be increased, operating power of readers can be reduced and portable equipment operating on battery power becomes more viable.

    In its simplest form, a transponder comprising a dipole antenna with a five volt logic circuit would need 54 milliwatts of power. For the past six years Trolley Scan have been providing passive transponders that could operate on just 200 microwatts of power - that is 260 times more efficient than a simple transponder and that could be read by a Trolley Scan reader at distances as far as 13 meters.

    Trolley Scan have in the past few weeks been developing a new design, one that operates on just 112 microwatts of power. This is nearly 500 times more efficient than a standard transponder and will give an operating range for a simple passive transponder of about 18 meters, while still being as small as a credit card.

    Passive transponders are dramatically cheaper and more green than their active transponder counterparts. There was a time when passive transponders had operating ranges of only 1 meter if you were lucky - and otherwise you had to use active transponders which contain onboard batteries. As the operating sensitivity of the passive transponders reduce so passive technology is replacing active transponder technology - reducing costs and increasing transponder operating life.

    The new transponders will be part of the standard RFID portfolio available from Trolley Scan within the next few months.

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