Light switches generate RF signals using own power


Staff member
ElectronicsWeekly posted an article about a company named EnOcean (a Siemens spin-off) which created a light switch wich can transmit RF signals by using the power generated from pushing the actual switch:

Its generators are piezoelectric, providing the 50µW required to transmit the switch's unique code, one of four billion available.

With 7N of force pushing a 3.5mm travel button, the devices transmit 10mW in three randomly-spaced 500µs bursts at 868.3MHz.

Read the entire article
I had seen some table top versions of this somewhere last year, but cant find it now. They were very attractive, with one or two large buttons. These would be great for end tables, desks, etc. Have them scattered around the house.
In my recent research regarding glass break sensors, I've seen some that were powered by piezoelectric gadgetrty as well. These devices use no power, but when they detect vibration, the piezos begin generating a current, once the current reaches a threashold, it closes a relay that's detected by your alarm system, Ocelot, parralel port, or whatever.

I'm surprised there are not more things that funtion this way.
Martin sells a glass break sensor which works that way, I actually bought it, but I just haven't had the chance yet to install this sensor.