Through the ROBUS CONNECT App, the ROBUS DOOR SENSOR CONNECT will alert you when your door or window opens. Use the sensor as a trigger for other actions to occur through the ROBUS CONNECT App. For example if the kids’ bedroom door opens, turn lights on in the hall so they can make their way to the bathroom and back. If the window opens, send a notification to let me know. All you need is 1 X CR123A Battery or micro-USB power and it’s good to go.