Complete instructions for this Weekend Projects can be found at

http://makeprojects.com/Project/Solar-Joule-Bracelet/22/1

The Solar Joule Bracelet combines two separate projects, a solar battery and a “joule thief,” to build a wearable circuit that powers an LED. Solar energy flows through the photodiodes, building up a supercapacitor, which essentially acts like a battery. This energy is then delivered to the joule thief, where oscillations eventually exceed the LED’s forward voltage, making it light up. Once fully charged, these oscillations will occur so fast that the LED will appear continuously bright, visible even during daytime!

Best of all, this circuit’s design allows you to install it where and how you wish!

This time around on “Tiny Yellow House”, Deek decided to mess around with passive solar heat so as to warm the always-cold front foyer of his home. The result: a smallish, closeable, passive solar collector that fits into a window opening. Its not rocket science (and it NEVER will be here on “Tiny Yellow House”) but it does work- even in January, in New England.

One of the great things about these little bots is that you can make them from scavenged materials. Use parts from broken electronics and bring them back to life as little robots!

Make your own backyard biodiesel. It’s easy to make a small batch that will work in any diesel engine. You won’t need any special equipment–an old juice bottle will serve as the “reactor” vessel–and on such a small scale, you can quickly refine your technique and perform further experiments.