If there is active vibration more than very low level, that can be tapped for small energy using piezos. But hey the small energy all the time X many collectors could build enough to power a low power circuit that is off most of the time.If you have a heat differential and Peltier wafers then you may be able power even more. Consider the girl in Canada who won the science fair with a flashlight that is powered by the heat of her own small hand. That flashlight doesn't shine seconds out of a minute though the beam is weak.Either way would need a boost converter rather than buck converter.Do it right and you can save having a person check and change batteries regularly.This works with regular diodes. It would work better for small taps with Schottky diodes but with strong vibration the voltage produced may be too much for those.https://www.youtube.com/watch?v=ReN_QU78pcsI've used this circuit to flash a led with a single finger tap and brightly with a single screwdriver handle smack. Honest, I was just testing suitability! It is also what powers leds in kids shoes that helps them be seen at night by car drivers when they run out in the street. Compare the energy in the steps of a small child to the energy in your steady vibration.The power is very low per squeeze but vibration is squeezes per second. Put the disc on the vibrating surface and a mass or mount on the other side and see what 1 disc can harvest. That would be for 1 disc. A Joule Thief can boost that steady low V to higher V charging pulses.If you have something that shakes then magnets and coils also become an option.Instead of tape you can use big heat shrink tube to make batteries into a pack.If you have a constant power trickle input, use a super-capacitor to store instead of batteries.