A free program for Android, by Jâvanware - Hobbyist.
You can use the volume buttons to power your phone up or down instead of the power button. It's useful if your phone is placed in a bag or pocket and you need to quickly wake up your phone to call someone or check the time. If you use the volume buttons regularly, it can also help you wake up more quickly.
How to use it?
To use the app, you have to install it first. You can do that by going to your phone's Settings menu and clicking on "Install".
After that, you will be able to install the app and you will be able to set it as an administrator. This is needed because only programs with device administrators have the ability to turn on and off the screen.