UPDATE: Texas Instruments has a neat little video on powering their MSP430 microcontroller from fruits and martinis! The Chronulator uses the same chip, although the meters draw substantially more current – you might need something bigger than a couple of grapes…
I want to try powering a Chronulator from some alternate power sources. Batteries and AC adapters are so boring.
The Chronulator requires 2.0 to 3.6 volts (V) and about 100 microamps (uA). That's a miniscule amount of power. So this should be easy. I'm thinking a potato battery, and a small (just a few square inches) solar cell.
For the potato battery, I'll likely need three or four "batteries" in series to get enough voltage. There should be plenty of current.
Since we can't count on the sun for power at night, the solar cell solution will use a super-capacitor. The super-cap will charge up with excess power during the day, and release it at night. I bought a super-cap from All Electronics a while back. Maybe I'll grab a RadioShack solar cell and see how this works in practice. I'm concerned that the super-cap might bleed down too quickly at night… But if this works, it'd be super-simple – no charging circuit necessary!