My iron man arc reactor is made from paper and card-stock. Inside it has a 9v battery connected to a 5v regulator powering an ultra bright white led. There are two wires with pin connectors coming out the back so i can power my breadboard projects with it.
I designed all the parts in Inkscape after looking at some images of arc reactors on Google.
This is the inner core that holds the battery and the 5v regulator (on the back of the perf board). The green and white wires connect to the led. There is are small switch on the back where the power leads exit.I made this section from 3mm foamboard. The whole thing fits snugly into the main body.