Lie Detector Simulator is a prank app that lets you simulate a lie detector machine to detect whether you are telling the truth or lying. The result will show your friend an indicator that will show if you are telling the truth or not. You can use the preset mode to make it easier for your friend to test whether you are telling the truth or not. The app also lets you control the result by pressing the volume key.

To use the app, you have to first set your friend's phone number in the preset phone number mode. You then call your friend and ask them to press the fingerprint scanner.