There are many situations when you want to turn on the lights but switch is out of reach. Normally you could use some sort of remote control or even better – do this without additional hardware. This is where old good clap helps.
CsabaP have built an Arduino based clap activated LED strip. The original idea was taken from knock activated drawer lock where drawer opens when secret knock pattern is recognized. Building blocks are pretty simple including Adafruit Trinket, white light LED strip, microphone module, and other necessary parts. Setup is pretty simple, but it can be great help in many areas.