The latest edition of Land Mobile Magazine (a magazine for professionals in the mobile radio business) has an interesting column showing how London Eco-Routemaster buses are being fitted with a novel sort of bell push (the kind you push to ask the bus driver to stop) which harvests energy from the action of pushing the bell to send a wireless signal through the bus to the driver. The bell push uses an energy harvesting chip from
EnOcean a company that specialises in such devices.
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The EnOcean evaluation kit (for professional developers) as shown on their website |
This is the first time that I've seen a very practical use for energy harvesting. I assume that the device "harvests" kinetic energy (from the pushing action) and thermal energy (from the finger tips) but it must generate a few uWatts for this to work. So, no batteries, no wires, wireless comms and good for 300k presses. There has to be a QRP application!
For more on this read the article on line at
Land Mobile magazine.