PIC MCU software library uses human body for secure communications link

2/28/2013 9:57 AM EST

Hey Steve, it's a really interesting concept, but the whole thing leaves more questions than answers. It's clearly a low-data-rate connection, but what's the min/typical/max? How does it vary with body conditions (level of fluidity etc..). The video shows it working with the device in a pocket: how many layers can it penetrate? What's the range?

So cool, but so vague at the same time.

Anyone see any immediate applications for this and would like more info to get moving? We can pursue this if you like.

2/28/2013 1:15 PM EST

Hello Patrick,

Before I answer your questions, I would like to note one caveat. All of our experimental testing only relates to our demo/development kit, in its current form. This kit was initially designed to mimic a typical automotive passive-keyless-entry system. With that being said, developers should keep the phrase “your application may vary” in mind when designing their particular implementation.

With the baseband chip we use for the demonstration kit, the carrier frequency is 125 kHz and we are using OOK transmission, which means that the highest data rate achievable is on the order of 10 kbps. In the development-kit implementation, we are only sending 1200 bps, which is good enough for a simple data exchange.

That said, this is all a limitation of our demo kit and not of the technology. In theory, you could use any modulation technique and run at any frequency, which means you could achieve gigabit-per-second transfer rates with the appropriate analog front end, if that is what your application requires. Of course, this would require much different hardware than what we use in our kit and would substantially increase the cost.

Our testing for some of the varying body conditions consisted of dousing the body in water (high humidity) and using higher concentrations of salt water (high humidity/sweat) and we observed no degradation of signal. We utilize both our capacitive mTouch™ technology and a proximity-detection scheme for the demo. The “range,” if you will, is scalable. This depends on how you configure our proximity function on the mobile-unit side. With our kit, we have it dialed in to about 4-5 inches, which means it will typically work in a pocket, purse or briefcase, as long as it is within that range. However, the sensitivity can be dialed up or down, depending on the application.

Edward Dias
Business Development Manager
Embedded Security
Microchip Technology Inc.

2/28/2013 1:21 PM EST

Hasn't this been around for a while now... seems to me this was touted as the "next big thing" that never took off. I did a quick search on Google and found a few things, though I recall a TV commercial (Intel?) where they demonstrated it. Some links:

http://www.psfk.com/2012/05/transfer-data-through-the-human-body-to-your-devices.html

http://www.taipeitimes.com/News/biz/archives/2005/03/20/2003247076

http://seminarprojects.com/Thread-data-transfer-through-skin-by-human-area-networking-full-report

http://www.trendhunter.com/trends/transfer-data-when-you-shake-hands

http://www.techradar.com/us/news/world-of-tech/future-tech/networking-the-human-body-opens-countless-doors-326496

Not taking anything away from Microchip - but with NFC and other short range data exchange technologes, I'm not "getting it"...

3/4/2013 2:24 PM EST

Hey Ed, thanks for chiming in and adding the clarifications. I like it for its simplicity and as a different option for getting a message from point A to point B using the body. One can imagine all kinds of fun ways to apply it.
mtripoli, while you make a good point, it's often been the case where a different comms approach gets the creative juices going. Looking forward to seeing where - or if - this inspires someone.