The term Internet of Things (IoT) was first coined by British entrepreneur Kevin Ashton in 1999, while working at Auto-ID Labs, specifically referring to a global network of objects connected by RFID (radio-frequency identification).
Over the past 17 years IoT has risen to be a ubiquitous term for all connected things as part of the cyber-physical industrial revolution, while RFID has taken a back seat to connected sensors. However, recent developments are putting RFID back at the forefront of the technological movement it started.
RFID is a system made up of electromagnetically responsive tags that can be picked up by specialised readers. Each tag can be embedded with unique information and attached to objects in order to track their presence and movement. To date, the RFID system has been somewhat limited to applications in which all tagged items must enter a “gateway” where readers are carefully positioned to pick up each tag’s signal as it passes through.
In the logistics industry, RFID tags have traditionally been attached to shipping containers, so as trucks carrying containers enter or exit the port the RFID readers at the gate would track their arrival or departure. In the manufacturing sector tags may be attached to components, such as car parts in an automotive plant, which can then be tracked as they move along the production line. People have also been carrying access cards embedded with RFID chips to pass through turnstiles on public transport systems in many cities for sometime.
While this variety of RFID applications may seem broad, they all still depend on tags passing through a gateway of readers. Recent-ish developments removing this limitation are now taking RFID to an entirely new level of potential applications, not least for the IoT.
Take enterprise IoT in the retail sector, for example. Stocktaking was once revolutionised by barcodes, where a rapid scan of an item’s code would register it, in the age of the Internet of Things however barcode users in stores with thousands of products might as well be using an abacus to count!
In 2014 retail giant Zara implemented RFID technology. “Before the chips were introduced, employees had to scan barcodes one at a time”, said Graciela Martín, store manager at one of Zara’s biggest outlets in Madrid. “These storewide inventories were performed once every six months, but because the [RFID] chips save time, Zara now carries out inventories every six weeks, getting a more accurate picture of what fashions are selling well and any styles that are languishing”. In this RFID system tags were placed on each item, then handheld readers were able to take inventories one rack of clothing at a time.
More recently California-based Mojix has taken RFID technology a giant leap further with their development of “Wide Area RFID”. Mojix was founded in 2003 by some of the world’s foremost experts in advanced signal processing technology perfected for deep space communications at NASA. Mojix have developed technology that can, continuing the retail example, take an entire store’s inventory in real time, any time.
Wide Area RFID refers to a fixed infrastructure, usually installed in the ceiling that can scan an entire space, recording all tags. While RFID tags cost just a few cents, the cost of each RFID reader can go into the thousands of dollars, so covering an entire warehouse or shop floor would be very expensive. Mojix identified the range limitation came from sending the signal to the tag, not from receiving the reply, so instead of covering a store ceiling with expensive readers, Mojix ran cables from the reader to antennas to cover the space, in a economically viable process they call “distributed excitation”.
While the cost of basic IoT sensors has come down to a matter of dollars (smarter versions in the tens of dollars), a passive RFID tag only costs a few cents. These economics mean a fashion retailer can tag every piece of clothing in a store; a supermarket could tag all of their tens of thousands of products, and in a smart building context we could tag pretty much every-“thing”.
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In a previous article Sensors, Sensors, Everywhere… we considered the implications of sensors on everything, but how does this debate change for passive tags (leaving out active tags as they require a battery that increases size and cost). “Passive tags” can store up to 8KB of data, although this has the potential to increase, which is generally limited to an Electronic Product Code (EPC), but crucially you can also see the item’s location.
For the Internet of Things, this development of a cheap way to identify an object and its location could have huge implications. Consider access control and personnel tracking in a building, factory or oil rig; or material and asset tracking within an industrial facility; official files could be tracked in a law firm or government office; livestock tracked through an agricultural facility; the nearest security or safety staff could be identified to deal with an incident at an event; medications could be tracked in hospitals, reducing theft and misuse…
While smart sensors enable us to access a variety of information gathered in real time, their cost and size limit their application. If the Internet of Things is to become the Internet of Everything, then RFID could play a major role in its future.