Home alarm system

Witness turns your Mac into a home alarm system, using its iSight camera as a motion sensor. If motion is detected, Witness sends mugshots and video to your iPhone or iPad.
Some apps offer a live video stream. While that sounds cool at first, it has many disadvantages. In contrast, Witness uses advanced motion detection to notify you right away when an intruder is detected.

If nothing happens at your house, Witness remains silent.
No need to interrupt you when everything is just fine.