I guess it's too much to hope that there's a drain or duct line under the circuit near the appropriate location? (For an RFID Loop) Why not have the unit on the cars do the timing, triggered by a beacon at the chosen spot, and then transmit the info to a PC. It could do the transmit thing several times to minimise (data) collision oppertunities. A 32kHz watch crystal should be more than adequate for timing. I see more difficulty in getting the beacon to trigger the device appropriately at an accurate location. Richar P "Alan B. Pearce" To: PICLIST@MITVMA.MIT.EDU Subject: Re: [EE]: Identifying cars Sent by: pic microcontrolle r discussion list 17/03/04 22:49 Please respond to pic microcontrolle r discussion list >Model cars use RFID tags for lap timing and seem quite reliable. I suspect that this is how the formula one and similar race cars do it as well. However in these cases I suspect that it is a permanently transmitting beacon seeing power is available. For the OP, is it not possible to have a slot cut in the track to drop a wire receiver aerial into, or is it a dirt/cinder track? If a hard surface then potentially any other uses of the track would probably also welcome having the receiver loop permanently embedded, even if each club had to own its own timing gear (maybe an opportunity to hire the gear you own). -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads