Monitors, as well as desktop with laptop LCDs, use an extensive amount of power. Yet most of us leave hours on and running all day (if not all night).

Sure, you can arrange Windows to switch off the display after a period of idleness, but that's less than ideal: moreover the delay is too short, meaning the monitor turns off when you don't want it to, or it's too long to do any good, efficiency-wise.
A British company called VeryPC just reveals a function called PecoBOO that merge your Webcam with facial-recognition technology. When you turn away from or go away from the PC, the software turns off the monitor. It turns it back on when your face re-emerge.

In a nutshell, you'll extract NirCmd to a database on your hard drive (I used C:\Nircmd for simplicity's sake), generate a shortcut to it, and allocate a hotkey of your selection to that shortcut, and then, if you feel like, choose a good-looking symbol to go with it.

Operates like a magic. Now, when I force down Ctrl-Shift-M, my monitor goes dark. A tap of any other key arouse it up again. The only defy I face is recollection to do this each time I get up from my chair but I skilled for myself to use other hotkeys, so this must be a gentle wind.