Microchip turns tag into touch
Bodycom uses a small, low-power module which you carry on your person. It does not have to be in close contact with the body, carrying it in a pocket is sufficient: but once carried, it enables you to make a “touch” contact with the other part of the BodyCom, a transceiver IC, via an electrode array. By analogy with an NFC tag system, the portable unit turns the user’s body into the tag and, enabling a low-data-rate exchange (up to 10 kbit/sec) over a very short distance – a touch or proximity contact. You can use it to connect securely to a range of wireless applications, with bidirectional authentication for advanced encryption technologies. Applications can see extended battery life by eliminating the need for a wireless transceiver or high-power inductive fields. No RF antennas are required, and BodyCom offers simple circuit-level design through use of the BodyCom Development V1.0 Framework, which is supplied through free software libraries that work on all of Microchip’s PIC microcontrollers.
BodyCom technology is activated by capacitively coupling to the human body. The system then begins communicating bidirectionally between a centralised controller and one or more wireless units. You can use the scheme, Microchip suggests, as the basis of a highly-secure channel with bidirectional authentication supporting advanced encryption, such as KeeLoq technology and AES. BodyCom technology help to prevent the “Relay Attack” problem that is typical in automotive passive-keyless-entry security systems, Microchip adds.
The list of possible uses is long, but includes keyless entry; enabling or disabling potentially harmful devices such as power tools (the product will only power-up when held by an authorised user); a similar solution for weapons; medical devices; or consumer electronics such as profile management for gaming consoles and exercise equipment. The “terminal” side of the transaction needs only to be equipped with a conductive array that can be touched by the user, similar to any touch-enabled device. The array can be shared with other touch applications and can be shared; and transparent ITO (indium-tin-oxide) conductors work well. Therefore, any touch-screen device might have authentication added and would only respond to users who themselves carry a validating tag.
Signals are conducted over the body (from touching finger to pocketed tag) at, Microchip says, picoAmp levels; antenna design is unnecessary, as the systems uses a low-frequency framework with a common microcontroller and standard AFE frequencies (125 kHz and 8 MHz), with no need for external crystals. BodyCom technology also eliminates the cost and complexity of certification because it complies with FCC Part 15-B for radiated emissions. More at www.microchip.com/get/GA5E
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