Ferrite uses a ferrite core and a vintage germanium transistor to step up voltage from a "dead" battery enough to light two white leds. Normally this would require at least 3.5 volts per led. The battery will continue to supply power till the battery is .2 volts dead. Circuit based on the popular circuit called a "joule thief". Will be shown at 2008 Maker Faire and Robogames. A CDS photo cell on top of its head allow the led to light only when its dark. Magnetic base under battery holder allows Ferrite to stick strongly on the steel base.