If you have $40 and a recent Mac with an iSight camera, then you have the makings of a simple home surveillance system thanks to Witness. Developed by Orbicule, Witness is a surveillance app that turns your Mac's camera into a motion sensor. The application runs in the background on your computer and will begin recording video or photos if motion is detected.
The system includes a free remote iOS app compatible with the iPhone, iPad and iPod touch. When an intruder is detected, Witness will send a notification to your iOS device and your web browser if it is open. Photos and video captured by the Witness app are available online and can be viewed using a web browser or via the Witness Remote application.
While it is not as robust as a dedicated multi-camera home surveillance system, Witness is an inexpensive alternative that would work well in homes where the computer is located near the door or other routes of entry. Besides intruder detection, it can also be used to spy on others in your house or office, which is especially useful if you want to find out who is lifting all the pens from your desk or stealing the cookies from the cookie jar.