Another project with an ATiny and a motion detector (like from RadioShack) where the author uses it to turn LED lights on and off and adjust the brightness of the lights based on proximity. The author build it own board too (single layer).
http://hackaday.com/2015/03/16/brighten-your-day-with-motion-controlled-cabinet-light/
http://hackaday.io/project/4451-motion-controlled-cabinet-light