I want to make a small very low (battery) power device that powers an ESP-201 on at the touch of a button, which does it's stuff, then automatically powers off after say 5-10 seconds.
That is to say completely powers off with no separate monitoring kinda circuit.
I've tried a couple things, such as with a relay but that ended up needing a separate power supply constantly running and also took up a lot of room physically.
Another attempt was with a capacitor and transistor which seemed to work alright, but I couldn't get a strong/constant enough power from it to run the esp8266 consistently (my electronics abilities let me down with this sort of thing).
Any ingenious ideas? Seems like a dead simple thing that everyone would want to do. I've even considered some kind of mechanically delayed latching switch, but they don't exist
Thanks in advance!