Why do you need a microcontroller at all then? Just use one of the radio remote control modules available. They are powered only if a button is hit.
If you want to have more control you can build one yourself with an ATtiny and this module: http://shop.boxtec.ch/link-transmitter-434mhz-p-41096.html.If you tell us more about your project we might give you more appropriate hints.
What is a uC?
What I am doing is I have a switch that has 3 positions (on-off-on) and I use the small transmitter to transmit the position of the switch to the receiver (receiver is connected to another Micro but that is just fine for this project).
Quote from: pylon on Apr 08, 2013, 11:50 amWhy do you need a microcontroller at all then? Just use one of the radio remote control modules available. They are powered only if a button is hit.If the end product is the goal (rather than the fun of making it) that seems like the most sensible option. There are various commercial radio and IR remote controls that can be used to switch things on and off - no need to reinvent your own.