I need to do a pilot project to check the speed of a moving car under a lampost. Is their any circuit which I can use to mount on a lampost and let a buzzer ring when a vehicle in its specific lane exceeds the speed of 45kph
Hardly a pilot project I'd have thought....You need to project a beam ( radar ) and receive it back and compute the time then compare it to a preset value.......
As it happens, there is a radar speed measuring unit just up the road from me....Shall I get it for you? (Joking...)
If you don't want to design the radar gun you could buy a kit like this: **broken link removed**
It has an doppler audio output that you might use to interpret as speed and trip an over-limit alarm.