Dual LED Pummer

A pummer is a BEAM robot that absorbs solar energy during the day (by charging up a large capacitor or rechargable battery from a solar panel), and releases it during the night, usually by blinking one or more LEDs. Think of it as a robot “plant”. The trick here is to get a circuit that is energy efficient (so can blink the LEDs for as long as possible once it gets dark), and blinks the LEDs in interesting ways.

Pummer front view Pummer side view

This a pummer that I built. It’s a dual LED pummer, based on a bicore circuit using a 74HCT240 chip. The circuit is described at the Solarbotics site (see schematic for a similar design that uses recharable batteries in place of the capacitor).

The frame of the pummer consists of three hard drive spacers; two for the base (a thin dark one on top of a larger aluminum one), and one placed vertically. Both the HCT240 and the 1F storage capacitor just fit inside their respective rings, which inspired the design.

The LEDs are super-bright blue and green. Because these suck up a fair amount of juice, this pummer only runs for about an hour after dark.

permalink | robots | 2007.11.19-22:31.00