Wind-powered Wi-Fi Sensors

Glenn Fleishman writes "According to an article at Indolink a 10-centimeter diameter windmill can produce the 7.5 milliwatts needed for a wireless sensor. The paper was published earlier (available as a PDF), but Nature magazine has apparently picked up the tidbit. The process flexes piezoelectric crystals to create a current. Although flywheels aren't mentioned in this article, it seems like a windmill, a flywheel, and a solar cell could in combination produce effective power in a range of conditions for remote wireless devices, including network relays obviating batteries entirely."

Comments

electric double layer caps

[Montressor]

Flywheels? The simplest way to store power would be an electric double layer capacitor. No moving parts. They can come in up to 70F at 2.1V - that's 140 C of charge. At 10 mW of power, 2.1V is 5mA of current; that means that it can stay above 1.5V for 2 hours. If a higher voltage is needed, put the capacitors in series. And these are not huge devices. Here's a datasheet for one

Re:not enough power for 802.11

[EnderWigginsXenocide]

A sensor need not be on the network 24/7. When it's onboard memory has been filled to a certain capacity (say 80%) if fires up the transceiver and transmits to the network. You only need peak power on occasion. Give your windmill plenty of time to charge up a big capacator (or a small battery.)