Saving energy by putting your computer to sleep has just gotten a lot easier. Sonar Power Manager is a free utility that will automatically put your computer to sleep whenever you leave your seat. SonarPM lives up to its name by emitting a low frequency from your computer speakers that is bounced back by your body and detected by your microphone. If you leave your computer then the frequency does not bounce back and your computer is automatically put to sleep.
SonarPM is an open source program that is free for download for all Windows(2000, XP, Vista, 7) and Linux users. You should test your speaker and microphone to see if SonarPM is compatible with your system. If you are not seeing any results you may need to re-calibrate your microphone and speakers before SonarPM works properly.
You can download and install this freeware from here: Sonar Power Manager
. Its worth giving a try.