Make an LED Throwie for 6 (six) cents - it's the cheapest Throwie ever!
are popular contraptions made of a battery, an LED, and a magnet all taped together. This version does not include a magnet, although it could.
This project uses the same principle as Tool Using Animal's Penny Battery
and Brenn 10's Penny and Nickel Battery
. It uses pennies as electrodes and vinegar water as an acid you make a battery that will power the LED.
The video that this is based on can be found here
If you like penny batteries, you're going to love the 500 lb. potato battery