I’m going to write this from a developer’s perspective, but don’t worry it isn’t going to be very technical. If you are looking for more information on what RFID is check out our RFID FAQ. RFID is a much touted technology that has not entirely fulfilled it’s potential. If you are contemplating using RDIF functionality in your mobile application you need to understand it’s strengths and weaknesses. It is far more accessible today than in the past.
Traditionally RFID has worked very well in closed-loop (on-premise) applications. For example, RFID tagging items and tracking their presence through an internal process, imagine a stock count of assets in a location. Until recently RFID has not been an affordable proposition for field operations in South Africa. This has changed because of the following reasons:
- RFID readers used to be very expensive, this is no longer the case. The price of built-in RFID scanners or sleds attached to rugged Android devices has come down dramatically.
- RFID smart tags, the actual passive tags attached to assets have also become very affordable. In the past the per unit cost of RFID tags was prohibitive. Now you can get fabric RFID tags (used for linen), RFID tags built into stick-on adhesive labels, alloy RFID tags that can be attached to high value assets and even plastic RFID tags at very affordable prices.
- The adhesives used to attach RFID tags to items have improved. Some of the 3M adhesive products bond so well that you will take away the metal of the asset if you try to remove them.
RFID tagging your assets
So what’s the catch? Well RFID reading isn’t a perfect science. When you pull the trigger on the RFID reader it reads or scans all the tags that are within range. This is dependent on the proximity of the scanner’s RFID reader and the quality of the RFID tags’ antennae. When an RFID reader reads or scans an RFID tag it returns an RSSI measurement – the Received Signal Strength Indicator. Occasionally given two tags, tag A which is closer to the RFID reader, and tag B which is further away, a reader will pick up tag B before tag A. So tag B has a higher RSSI than tag A. This means you cannot always infer the proximity of the asset by the RSSI signal. This underscores the need for a strict methodology when applying RFID tags to assets. When you RFID tag an asset for the first time, you have to isolate the RFID tag intended for the target asset from all the other tags you have on you (to be used to tag other assets). For the initial asset identification you must ensure you have correctly captured the RFID tag attached to an asset by placing the unused RFID tags in a shielded container.
Once you have your assets RFID tagged you can pull the trigger on your RFID scanner and identify all the assets very quickly. In a matter of seconds you can verify that all the requisite assets are at a specific location. This is a much faster alternative to scanning barcodes. Imagine RFID tagging all important equipment in an ambulance and then verifying that they exist by doing a quick RFID scan.
Finally you should consider what to do when you perform an RFID scan and find that you have missing assets or extra “unexpected” assets. When an asset is missing you probably want the system to automatically log it and send out a notification to the relevant person.