> I think the problems with a system like that would be first of all the speed > of the passing cars, do people buzz through toll booths at 75MPH? > > Secondly, unlike toll booths and railway tracks, these cars could be coming > through the timing point at a number of different angles relative to the > beacon, which would make the reading of barcodes very difficult. Don't know what the device is but the local expressway has 'open road' lanes where you can blast through at highway speeds, these things are characterised by a couple of wires hanging over the road with the reader device on it. On a smaller scale the local rc car club runs it's races with some similar method with a windshield mounted 'transponder' and they drive under a wire mounted on a PVC pipe to count laps. -- Anthony Toft -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads