Rfid distance measurement

Custom engineered sensor systems — Adapting our sensor technology to your needs is our specialty. To get the optimal performance, custom-designed and optimized antennas are required. Several UHF RFID sensor technologies supported — which allows us to find the best chip and electronics design match for your special sensing need.

rfid distance measurement

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rfid distance measurement

Nearly foot read range with hand-held readers. Our new sensor technology has revolutionized RFID sensing! Batteries that can last over 10 years make these wireless sensors practically battery-free. Available in standard sizes that are optimized for different types of equipment monitoring. A breakthrough in RFID sensing. Ideal for equipment monitoring.

Our wireless sensors are small, quick to install, and enable rapid data transfer to a reader that archives the data. Contact us if a different temperature range is required.

Custom configuration and packaging available for unique or rugged applications. Humidity and temperature, pressure, strain, and more. Contact an Expert Email Us. This long range opens the door to use wireless sensors in many new, innovative applications.

Smaller than a credit card. Ultra-miniature options available. We offer many types of sensors: humidity, pressure, strain, etc.

No batteries make these sensors virtually maintenance-free. Our specially designed and optimized antennas make it possible for RFID sensors to transmit through metal. How do you want to use long-range RFID sensors? A streamlined approach to sensors. Learn More. Passive Battery-Free. Available in standard credit card size. Available in several sizes for different metal-mounted monitoring applications.

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If the answer is 'No - not according to the standard', would it be possible to build a reader with this feature? I guess the only way to achieve this would be to measure the time between call and response very precisely.

There are mainly two ways this can be achieved: The first one relies on getting the RSSI, which is basically the signal strength. The main difficulty using this indicator is that signal strength depends on a lot of factors that can influence it like, reflections if the signal needs to pass a wood cabinet or a wall, the quality of the tag, etc.

The second one is use the time the response is received to an enquiry Time Differece of Arrival between tags. Given that you know the speed of the beam you can estimate the distance given a very precise timer. The problem here is that this also is influenced by a lot of factors: the mean time the tag needs to complete a cycle which you should know, and should be the same for every tag usedthe timer precision which is not built precisely for these purposes.

Naturally a combination of both should be employed for maximum precission and both are actually used by companies that rely on these algorithms to provide RTLS Real Time Location Systems application through Triangulation and Trilateration.

It is possible. As far as I know the company below I'm not working there, I just happen to know someone who worked there a year before :. It may not be possible if you have a single reader; however if you have multiple receivers and reasonably clear lines of sight"estimating" the distance becomes possible by looking at signal strengths. This is at least in part because the RFID was not designed with an output pattern that helps optimize localization, such as a frequency chirp, short power bursts, or other modulation features that allow estimating the time of flight of the signal from source to receiver and back.

In free space, by using the above equation, the approximate distance to RFID tag may be acheived. Learn more. Calculate distance to RFID tag? Ask Question.

Asked 7 years, 3 months ago. Active 11 months ago. Viewed 30k times. Peter Mortensen Probably not with time delay, but possibly with signal strength. I actually read a paper about it two years ago. It was related with power dBsome Asian guys were researching about it. Active Oldest Votes.All Videos. Search for:.

rfid distance measurement

Subscribe Login Search. InnerSpace's inFORCE solution can detect the locations of workers or the public as they move around a space, thereby facilitating social distancing, emergency response and crowd management. Kerlink's LoRaWAN solution is capturing radon measurements at Mount Etna's craters in real time, so that researchers have access to data and analytics related to conditions that could lead to an eruption.

The company is working with warehouses and suppliers to provide a kanban-based solution employing its ARU reader with FAKRA connectors that enable the quick connection of up to 24 additional antennas to capture automated tag reads on shelves.

Face-to-Face Events. Now in its 18th year, LIVE! The conference program features mo Learn More. Online Events. They may be skilled at deploying bar-code systems, but RFID requires special expertise. In this webinar, you will Europe Report Throughout Europe, radio frequency identification technologies are being deployed at large, midsize Smart Packaging Plays a Key Role for Brands and as a Marketing Tool Increasingly, products are being made available for sale through e-commerce and by companies with li Retail Report RFID technology is being deployed at stores and warehouses around the world to improve item-level in Iris Nova Manages Honor System Beverage Sales For decades, the non-alcoholic beverage industry has been dominated by sugary drinks sold at high vo Carnival 4.

Address Line 1. Address Line 2. State or Province. Zip or Postal Code.RFID range is fundamental. Some RFID systems will only work over a few inches or centimetres while others may work over metres feet or more. While chosing an RFID system with an RFID range of a hundred metres might seem attractive, the technology that enables this may not support some of your other needs, such as minimizing costs by allowing you to use inexpensive passive tags.

And while you can control some of the things that affect RFID range, you may not be able to control others. They may only work at 20 metres in some applications. Active tags have a batteryor an external power supply, so have enough power available to allow them to transmit up to the maximum legal power limit. It needs to get the energy from somewhere.

The answer lies in the RF energy that the reader transmits. The higher the transmit power the greater is the RFID range. This could be serious if they were part of a critical medical application.

Each country puts a limit on the transmit power that a reader or active tag is legally allowed to transmit, and this is enforced by law. Without these limits, a radio system would be chaotic and unworkable.

Active RFID vs. Passive RFID: What’s the Difference?

Different countries have different regulations and specify the maximum amount of power you can use in each frequency band. The amount of power that the tag needs to get from the reader to enable it to operate is important.

In fact, if you were a tag designer you would work hard to minimize the amount of energy needed to power the tag. The working distance between a reader and a passive tag is greatest when they are in tune. An active tag usually gets its power from an internal battery, so has enough energy available to enable it to transmit at the maximum allowable power.

These allow active RFID tags to operate at a much greater range than passive tags. Some tag manufacturers are now claiming that their tags have a battery life of up to five years. This depends mostly on how often the tag transmits. Both a reader and a tag have an antenna.

To enable data communications each must be able to receive some of the transmitted RF energy from the other so the information can be recovered, from the RF carrier, and used. A simple whip antenna radiates RF energy in most directionssimilar to the way a light bulb radiates light energy in most directions. Some types of antenna focus the radiation into a beam. Have you seen the Yagi antennas with the directing cross bars on them?

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Those direct the energy into a beam. The more directors an antenna has, the narrower, or more focused, is the beam. But the narrower the beam, the more accurately you have to aim it, as the target area is smaller and the tags have to be closer together.

Any other radio receiver within the influence of this concentrated beam might also be influenced… adversely. You need to limit the power you transmit from the antenna and this depends on the type of antenna you use. If the antenna radiates in all directions isoptropicallyyou could put 4 Watts in to the antenna and the EIRP would be 4 Watts out. To recover the ID information from a tag the RF signal has to be stronger than any unwanted background electrical noise.

If a signal is weak, you may need a high-gain antenna to capture enough RF energy This way you may get enough RF energy to enable you to recover the ID information. This uses the magnetic component of the electromagnetic energy and this couples the tag and reader over only very short distances of typically up to half a meter, or just over a foot. This is fine in applications like card readers where you bring the tag up close to the reader.Introduction: First of all, we want to excuse us for our bad English.

German pupils :D We invented a new, inexpensive device to measure distances up to 1. The use of radio waves makes it possible to measure without the target being in sight. This means, you can measure distances through whole buildings. There are many rangefinders available, which are working with sound waves or lasers.

A disadvantage of distance measurement with laser rangefinder is that you must center up the beam to the receiver and ensure that there are no obstacles along the laser beam.

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It is used to stop the time the emitted radio wave is travelling. Because the spreading rate of radio waves is identical with velocity of light, you can calculate the distance between the two devices measuring points by a given travel time of the radio waves.

To display the stopped time, binary outputs of the decade counters must be converted to be easier readable on 7-segment-displays. The process of a single measurement: 1 The measurement is being initiated started with a button by the user at the basic station 1st point 2 Counter starts, at exactly the same time a MHz AM transmitter module emits out a 1st radio wave 3 The radio wave gets into the receiver at the 2nd point, and immediately starts the 2nd transmitter at a frequency of MHz 4 The MHz wave is being received at the basic station and stops the counter 5 The travelling time can be read on the display.

Increasing the frequency of the time base will improve the accuracy: The higher frequency, the more precision. Although there are several crystals available on the market with frequencies up to MHz 5th harmonicthe actual limit is the maximum clock frequency input of the 74HC counters with 53MHz.

Farnell offers counters up to MHz, but they are expensive, only available for companies and come in boxes with hundreds of it. Another problem is that free frequency bands and MHz in Europe can be used by any other equipment like walkie-talkies. This means the device will not work, because the receivers will get some other signal that is in the air.

The picture shows on the left side the distance measured by out device. The real distance is plotted on the ground.

Why the ‘Experts’ Don’t Recommend RFID

To prevent errors, several measurements had been performed. The fist one is shown by the blue line, the second by the red one an the real distance is located by the orange one. Step 6: Trilateration Suppose you built such a unit, you may ask yourself if distance measurement only is a bit boring. Good news: If you built three of these, you can use them for trilateration.

The intersection of two spheres is a circle. The intersection of three spheres is one point. This can be used tracking an object for example a car GPS uses exactly the same principle. Step 6: Conclusion This new technique of measuring distances is a great alternative to conventional laser methods. But the largest advantage is that you can measure through whole buildings.

And the way it is built up is also simple enough to push this project easily forward with minimal knowledge of electronic.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts.

It only takes a minute to sign up. I want to make a project on an anti-collision system using RFID. I'm facing many problems selecting RF reader and tag: the required UHF generator, tags and reader are expensive.

There are versions which are longer range, but these versions actually make triangulating a position more difficult. Only then can the tag respond with its ID. The bit rate is also relatively slow. This will reduce the reaction time of your collision avoidance system. Even if you could get one, there is no guarantee that it would work for your application. You could try to roll your own RFID solution that would work for your application, but it is more likely that engineering a proper solution and not trying to force RFID into this application would give you better results.

If I were doing this project, I would be looking into those cheap radar units that are currently used in cars for collision avoidance. They are mainly used in the rear bumper to detect objects when backing up, but they are being used more and more in cars facing forward for break assist and cruise control stuff.

Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to measure distance from moving object using RFID? Ask Question. Asked 7 years, 4 months ago. Active 7 years, 3 months ago. Viewed 3k times. RD meena RD meena 13 1 1 silver badge 3 3 bronze badges.Radio-frequency identification RFID uses electromagnetic fields to automatically identify and track tags attached to objects.

An RFID tag consists of a tiny radio transponder; a radio receiver and transmitter. When triggered by an electromagnetic interrogation pulse from a nearby RFID reader device, the tag transmits digital data, usually an identifying inventory number, back to the reader. This number can be used to inventory goods.

There are two types. Passive tags are powered by energy from the RFID reader's interrogating radio waves. Active tags are powered by a battery and thus can be read at a greater range from the RFID reader; up to hundreds of meters. Unlike a barcodethe tag doesn't need to be within the line of sight of the reader, so it may be embedded in the tracked object. RFID tags are used in many industries. For example, an RFID tag attached to an automobile during production can be used to track its progress through the assembly line; RFID-tagged pharmaceuticals can be tracked through warehouses; and implanting RFID microchips in livestock and pets enables positive identification of animals.

Since RFID tags can be attached to cash, clothing, and possessions, or implanted in animals and people, the possibility of reading personally-linked information without consent has raised serious privacy concerns. Tags can also be used in shops to expedite checkout, and to prevent theft by customers and employees. Sound waves vibrated a diaphragm which slightly altered the shape of the resonatorwhich modulated the reflected radio frequency. Even though this device was a covert listening devicerather than an identification tag, it is considered to be a predecessor of RFID because it was passive, being energized and activated by waves from an outside source.

Similar technology, such as the Identification friend or foe transponderwas routinely used by the allies and Germany in World War II to identify aircraft as friend or foe. Transponders are still used by most powered aircraft. Mario Cardullo 's device, patented on January 23,was the first true ancestor of modern RFID, [6] as it was a passive radio transponder with memory. It consisted of a transponder with 16 bit memory for use as a toll device.

The basic Cardullo patent covers the use of RF, sound and light as transmission carriers. The original business plan presented to investors in showed uses in transportation automotive vehicle identification, automatic toll system, electronic license plate, electronic manifest, vehicle routing, vehicle performance monitoringbanking electronic checkbook, electronic credit cardsecurity personnel identification, automatic gates, surveillance and medical identification, patient history.

A radio-frequency identification system uses tagsor labels attached to the objects to be identified. Two-way radio transmitter-receivers called interrogators or readers send a signal to the tag and read its response.

RFID tags are made out of three pieces: a micro chip an integrated circuit which stores and processes information and modulates and demodulates radio-frequency RF signalsan antenna for receiving and transmitting the signal and a substrate.

About Ultra Long-Range UHF RFID Sensors

The RFID tag includes either fixed or programmable logic for processing the transmission and sensor data, respectively. RFID tags can be either passive, active or battery-assisted passive. An active tag has an on-board battery and periodically transmits its ID signal.

A battery-assisted passive has a small battery on board and is activated when in the presence of an RFID reader. A passive tag is cheaper and smaller because it has no battery; instead, the tag uses the radio energy transmitted by the reader. However, to operate a passive tag, it must be illuminated with a power level roughly a thousand times stronger than an active tag for signal transmission. That makes a difference in interference and in exposure to radiation.

Field programmable tags may be write-once, read-multiple; "blank" tags may be written with an electronic product code by the user. The RFID tag receives the message and then responds with its identification and other information.

This may be only a unique tag serial number, or may be product-related information such as a stock number, lot or batch number, production date, or other specific information. Since tags have individual serial numbers, the RFID system design can discriminate among several tags that might be within the range of the RFID reader and read them simultaneously. An Active Reader Passive Tag ARPT system has an active reader, which transmits interrogator signals and also receives authentication replies from passive tags.


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