or maybe you can write a program that deccodes the different signals... ya, unless you can think up of an easy way to do it (different timmers spitting out the data on a printer or somethin), i have sadly no clue what to do, if you just want laps only and don't really care about times you can consider using the LM555 timer to make a pulse circuit and then have that transmit the weak signal that gets picked up, and gets decoded by a simple bandwith filter (make shure to have the bandwith different from that of the transmitters and have a large difference between them in frequency terms), and rig the outputs to a resetable counter unit and bingo there is a somewhat complex way to do things, ill try and get some pics of a transmitter reciever circuit working (maybe somethin intnded for ultrasonic range finding can work???)