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Established in 1999 as a limited company, based in High Wycombe, Skillweb's core business is the design, development and through-life support of mobile computing solutions. Our proven solutions are in place with customers like DHL, British Telecom, Lynx Express, Isle of Man Post Office, Air Products and many more.
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Technical Challenges
In this section of the ezine, I propose to examine topical technical challenges, hopefully exploding the myths.
I start off with RFID and the myth that you can take a supermarket trolley full of product, walk through a gate and every tag will have been read, triggering payment from your credit card. This is the same myth as the trailer full of goods on RFID tagged pallets passing through a gate and all goods being counted with 100% accuracy.
Here is the truth, tags on products or pallets have to obey the laws of physics. If they are to be ‘illuminated’ and therefore ‘respond’ to the transmitted radio frequency wave, the power output of the transmitter and its associated read sensitivity has to overcome the obstacles of metal, the absorption of water and the distance involved. RF waves bounce and create patterns of waves; remember your experiments with iron filings and magnets; these bouncing waves can create blank spots. It’s why modern microwaves have rotating turntables to avoid RF dead spots and to ensure the food is cooked uniformly. In our supply chains it might therefore be possible to miss a tag through dead spots, however circular antennas and multiplexing techniques can avoid this. Water and metal are more complex; metal will mask tags, whilst water will absorb the radio wave energy. It makes the ubiquitous can of coke a difficult product to tag! Critically in the future the can might become the tag and the content used to tune the antenna, a few years off yet though! The biggest challenge though is not the single read of a single product but the complex read of multiple products and multiple tags in close proximity to each other.
The answer is that the 100% read of the shopping trolley or pallets on the back of trucks is a long way off – however this doesn’t negate the use of RFID in the supply chain – simply the best use is elsewhere at the moment. We’ll explore where in the next ezine.