How to take screenshot on android
Truth be told, it works on the device only if the device is rooted, screenshots on non-rooted android can only be taken via ADB and eclipse on PC.
The app is called ShootMe, allows you to take screenshots of your device.
How to take screenshots: Launch ShootMe and shake your phone and then hide the app. Now navigate to any screen in any app and Shake your Phone to take screenshot. Alternatively, shout loudly to take a screenshot.
When not needed, you can switch it off using MENU.