This is an infrared motion sensor module, commonly found on lights that automatically turn off. They use infrared sensors to detect movement and if any motion is detected, the alarm signal will go low. This device requires a 5-12V signal to operate.

Typical applications are for intruder detection, automatically turning off devices when no movement occurs (might not be good for TVs), and if you get clever, taking snapshots of pests or wild animals.

Note: this device uses a bizarre wiring configuration where the red wire is VCC, brown wire is GND, and the black wire is the alarm.