Mobile RFID readers

I wrote yesterday about passive RFID tag technology. I found (via Ars Technica) an interesting application of RFID tags that reverses the standard RFID setup by having fixed tags and a mobile reader. The tags reside at fixed locations and beam a transmission when a reader approaches close enough (a passive tag would be activated by the proximity of the reader). The applications explored in this article are to (1) navigational systems for the visually impaired and to (2) guidance systems in locations such as museums.

Looking ahead to when large numbers of devices around us sport RFID tags, a number of applications will arise for mobile readers that can extract relevant local information from the tag environment around them and resolve this information using access to Savant and ONS systems over a ubiquitous wireless network such as GPRS or WiFi.

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Reader chipsets will be embedded in laptops and PDAs connected to the Internet through whatever wireless connection is available. In this scenario, you will want access to more just than the EPC, the manufacturer, the product name, etc. - you will want to know what the product features are, what the cost is, where the nearest store is where it can be purchased, etc. You will want to be able to scan and parse the (presumably large) universe of tags around you at any given time. Environmental RFID tags will provide mobile robots (bearing RFID readers) a means of gathering information about the immediate environment and navigating it.

This vision is a little different from that of sensornets in the following respects: (1) RFID tags are passive transponders, activated only by the immediate presence of a reader; therefore they can be much cheaper(2) RFID tags do not communicate with each other, (3) RFID tags will be embedded in all devices and products, hence near-ubiquitous. By contrast, sensors will only be placed in pre-designated locations (4) RFID tags will will have little or no processing power because of cost-constraints and will only be capable of communicating a limited information set, (5) the RFID communication protocol will have to be standardized since it will have to work between arbitrary tags and arbitrary readers whereas there is no a priori driver for an interoperable communication framework for networks of sensors.

I'll have more to say on this soon.