I have a very small display box that I would like to illuminate with a couple of white led's. I want to push a button to light them up, and then they will turn off automatically after 10~30 minutes. I have a 3V power supply, and some NE555 chips, and I'm looking for a diagram that a woodworker can follow. If this is covered elsewhere please accept my apologies and point me to it. Thanks guys.

 

your going to struggle with 3V for a 555 timer, the leds will probably have a voltage drop of 3.4V.

 

Biggestl problem: NE555 does not work properly at 2.5V, which is what your batteries will sag to.