Anyway, during the long (6 hour) drive we (as generally happens during long drives on British roads these days) touched upon the subject of speed cameras, bane of the motorist. Now, before I begin, let me just be clear, I'm not a raving loony (well, depends on who you ask I suppose) who wants to go tearing round the countryside at 100 miles an hour. It does, however, nark me when we go through miles of road works with 50 mph average speed cameras and see not a single soul working on them.We mumbled away about how easy it would be to make an anti-speed camera device, in the end coming to a quite surprising solution. Our thought process was basically this:
Speed cameras work using the Doppler Effect; by looking at the apparent frequency shift of a known pulse after it has been reflected off the moving vehicle (see below). In order to prevent said speed camera from catching you, you require some way of scrambling or cancelling this reflected signal. The optimal way of doing this is to emit a phase inverted (upside down) version of this reflected signal. Now, the signal being reflected back to the speed camera is itself the phase inverted version of the original signal emitted by the speed camera as a result of the reflection process.
So, the easiest way of making yourself an anti-speed camera device is to steal a speed camera and mount it (discretely, of course) on your car...
