Prevent Tampering with CCTV

Many priceless art objects in museums and galleries are protected by CCTV cameras trained upon them. The operators are thus alerted to any attempted theft.

However, as any self respecting jewel thief knows, this precaution is easy to circumvent by simply making a looping tape of the scene, and playing this back through the camera cable. The momentary interuption of the picture while the connection is switched will certainly be missed by the operator, who, at the time will be:

1) studying a naughty magazine

2) arguing with a collegue about baseball scores

3) on the toilet

Even if he does notice the break, he will ascribe it to an temporary electrical fault, slap the monitor, and continue with one of the above.

I propose a simple device to thwart this devious technique. This is a box with a lamp on it. The box has a clock and a secret key code. Every second, the box combines the time and the key, and either flashes the lamp, or does not. A piece of software receiving the camera feed, which also knows the time and the correct key, watches for these flashes. If an incorrect sequence is received, the alarm is sounded.