NOTE: You’ll need to have a CR2 3V Lithium battery.
To change the battery in your door / window sensor, follow the steps below.
1. Remove the sensor from your door or window
2. Remove the cover
3. Remove the battery
4. Insert the new battery
5. Put the cover back on
a. The light will blink and automatically connect to the hub.
6. Place the sensor back on your door or window