The Sonar Power Manager uses a new user presence detection technique to shut off the computer display when you are not present. The goal is to shut off the screen immediately after you leave, even if you just moved the mouse 10 seconds ago.
Make PC sleep when you move away
It uses a very simple type of sonar system to accomplish this: The Sonar Power Manger uses ultrasonics (sound above 20kHz in frequency and which humans cannot hear) on your computer’s regular sound system.
While most laptops can use ultrasonics, some cannot. In such cases, the Sonar Power Manager will not properly detect user presence or produce annoying lower-frequency harmonics or noise while the sonar is operating.
This freeware was developed along with researchers at Northwestern University and the University of Michigan.
Visit Sonar Power Manager HomePage to read more and download it.