For a while now I've wondered if rain drops falling on a piezoelectric crystal could light up an LED. I pictured having a whole array of these outside being lit up. Over the past two weeks I finally tried it. It's a lot harder than it seems.
First of all, unless it's really raining hard it won't do it - at least not with the crystal I used, a piezoelectric disk taken from a musical gift card. So I ended up making a fancy contraption that captures the rain and then meters out drops of a fixed size and maximum rate and makes them fall around 4 feet before hitting the disk which powers LED. It took a lot of trial and error and versions, but it works, when it rains.
Anyhow, details are here:
http://rimstar.org/sdenergy/piezoelectricity_from_water_rain.htm
including a video. Or you can just watch the video without all the details directly from here:
http://youtu.be/laSQ6yd7jaE
Sadly, I can't see it's worth pursuing further. Oh well. Seeing as how there's interest here in piezoelectricity, I thought I'd share. I'm sure it'll give someone ideas.
-Steve
http://rimstar.org http://youtube.com/rimstarorg
How about this: http://www.impactlab.net/2019/02/14/generator-that-creates-electricity-from-gravity-could-revolutionize-renewable-energy/ (http://www.impactlab.net/2019/02/14/generator-that-creates-electricity-from-gravity-could-revolutionize-renewable-energy/)
Or this: [size=78%]http://windulum.com/page0/page0.html (http://windulum.com/page0/page0.html)[/size]