Popular Science’s Theodore Gray show you how to power a string of LEDs using a chain of five homemade gravity-cell batteries – Link.
- Tomato soup battery and more – art by Ben Woodeson – Link.
- Penny-Powered LED – Link.
- Powering LEDs costs mere pennies – Link.
From the pages of MAKE:
- Penny-Powered LED. Power an LED with some salty water and $1.21. Subscribers–read this article now in your digital edition or pick up MAKE 07 in the Maker store.