an eloctronic counter

[sushant]

I am going to do a project in which an electronic circuit that can count the number of vehiclespassing across during a particular interval is to be used and another signal proportional to that no will be fed to another part of the circuit.I think i can use a laser beam counter but the problem comes in producing signal proportional to that number.What can I do?[/list]

 

[Nigel Goodwin]

I am going to do a project in which an electronic circuit that can count the number of vehiclespassing across during a particular interval is to be used and another signal proportional to that no will be fed to another part of the circuit.I think i can use a laser beam counter but the problem comes in producing signal proportional to that number.What can I do?[/list]

It's usually done by placing two 'switches' across the road surface, probably just tubes full of air which activate pressure switches at the side of the road - it's quite common to see these across the road, connected to a box with a recorder inside.

What is the proportional signal intended for?, feeding a chart recorder or something like that?. If so, presumably you only need to update it at certain intervals - it looks like another fine project for a micro-controller, use that to do the counting, and after the required interval output the current count via a D2A converter.