Switchbot Contact SensorWindow & Door Alarm Sensor for Home SecuritySwitchBot Contact Sensor can detect the opening closing of doors and windows, guarding security of the elderly, children, and pets. With the built in light sensor, it will automatically trigger the Switchbot Bot to turn on the light when someone moves when the environment goes dark. Detects People Leaving or Entering the HomeWith the built in motion sensor, Contact Sensor will know whether you are leaving or