You can configure Windows to automatically turn off the monitor after a specified time of inactivity. This can be done from power options in Control Panel, but this method has a couple of disadvantages.
The first disadvantage is that if you set a very low time ( e.g 2 minutes), the monitor will turn off every now and then. This becomes irritating if you are watching a movie or delivering a presentation and do not move the mouse for some time.
Increasing the inactivity timeout to a greater interval has other limitations. For example: you leave the desk for a quick coffee break and the monitor remains on for the whole amount of time.
What if we had a software which can detect user presence and turn off the monitor automatically?
Enter Sonar Power manager – a better power management alternative for Windows. The software uses ultrasonic sound to detect whether you are present in front of your computer or not. These sounds are above 20kHz in frequency and which humans cannot hear. Hence, it can be used to automatically turn off the computer display, when you leave the desk.
Using the software is quite simple, after installation hit the configure button and the application will start recording the sonar readings as shown below:
How it works: Sonar Power manager releases sound signals of very low frequency and reads the echo after the signals hits your body. The software will calculate an average of the sonar readings and store it in it’s memory. When you leave the desk, these sonar readings will fall which will trigger the application and it will turn off the computer screen. When you come back, simply move the mouse and the display is back again.
However, you can not use the program to turn off or hibernate your system. Thanks to Ankit Prakash for the tip.
Tip: Mute Computer when Windows starts from hibernation or Logged Off Modes