I want to build an programmable animal feeder to dispense small amounts of food.
Rather than deal with some complex auger or motorized system, and worrying about it jamming, or dispensing too much, etc. I decided the most simple and efficient way to do this could be to just build a few small compartments, that basically have a trap door at the bottom (the device will be hung from above).
That has the benefit of perfect proportions, nearly impossible to jam even with almost any shaped food, simplicity, small size, and very low power usage because gravity is doing most of the work.
However I'm having a tough time figuring out what sort of release mechanism to use to let the trap doors drop open. I want to make this whole device battery powered so the less power usage the better. It would be nice if they could be triggered with less than 40ma so that they could be triggered directly from an arduino pin with no relays involved. Just need to pull a pin, or open a latch, or something like that. Any ideas?