Ben Tongue’s article on using a supercapacitor to hold energy harvested from an antenna tuned to strong local broadcast system got me thinking about supercapacitors again. Digging around uncovered a link to a DIY project (very simple) for creating your own electric screwdriver powered by supercaps. (I think they are a bit cavalier with the charging circuit, which basically just dumps the current from a USB port into the caps without any leveling or the like, but shrug….) One interesting thing that I found was that SparkFun apparently carries 10F (yes, 10 farad) 2.5 volt supercaps for around $5. Neat!

Make an Instant-Charge Screwdriver | Popular Science

Addendum: Here’s an even simpler project to power a flashing LED.