From household pets and tollways, through to goods in transit and railway cars, RFID tags are appearing in more places, making it easier to track and identify objects.
RFID, or radio frequency identification, tags are small electronic devices that contain information and can be scanned, a bit like a barcode. But unlike barcodes, RFID tags don’t need to be ‘seen’ by the scanner and multiple tags can scanned at once.
The technology behind RFID was first used in 1945 by Russian scientist Léon Theremin to create a listening ‘bug’ called The Thing. But it wasn’t until 1969, that US engineer Mario Cadullo designed and built the first RFID tag.
Although there are a few variations, RFID tags consist of a silicon chip processor and a metallic antenna. Some, known as active or semi-active, also have a tiny battery. Tags without a battery are called passive.
When a tag passes near a RFID scanner, energy from the scanner’s magnetic field is collected by the tag’s antenna and converted into electricity. This provides enough energy for the tag to transmit a radio signal back to the scanner, which contains information stored on the chip.
The chips, depending on their size, contain either 96 bits (12 bytes) or 2 kilobytes of information.
Although the signal transmitted from a passive RFID tag is weak, can it read by scanner several metres away. Active and semi-active tags are used on large items, and can be scanned from up to 30 metres away.
One of the first wide-spread uses of RFID tags was ‘microchipping’ cats and dogs. A plastic capsule, containing the chip and antenna, is insert edunder the skin of the animal. When a scanner is waved near the tag it receives a unique code that can be searched on a database.
As tollways increasingly become ‘cashless’, car owners are being encouraged to install eTags to their car windscreen. As the car passes through a toll gate, the scanners activate the eTag, which contain an active RFID that transmits its unique code.
RFID is increasingly being used by manufacturers and retailers to track the movement of goods from the factory to the store. Australian ePassports also use RFID technology, allowing more information about the owner to be stored in the passport and for faster processing at customs.
In the future, RFID tags could appear in the packaging of individual products. This will help retailers know how long the product is on the shelf and could double as an anti-theft device. Your fridge and pantry could also have RFID technology, which would scan our food and alert you whenever an item is approaching its ‘use by’ or ‘best before’ date.