A free app for Android, by DiordnaApps.
Motion Detector is an application that allows you to monitor the movement of objects around you. It's designed to work with the phone's built-in camera, so you can use it to detect movement anywhere you want. The program is very easy to use.
To begin using the application, open it and select the option to activate the camera. The next step is to place your phone in a place where there is no movement. Do not hold the phone with your hand, but place it in a solid place. The phone's camera will be pointing at the objects, so when an object is in front of the camera, it will be detected and the sound will be played.
If you want to deactivate the motion detector, simply press the pause button.
