Because I keep daydreaming about wiring up my house with dozens of sensors, I was wondering how hard it would be to power a micro controller (say picaxe) off a super capacitor.
A supercap is an electrolytic capacitor with an insanely large capacitance. Mine is half a Farad, 470000 uF. But is rated for only 5.5 V. That's the deal with these caps. Higher capacity at the expense of the maximum voltage they can endure. Or simply at an expense. This one costs about $4 at DigiKey.