Maybe try a voltage to frequency method. Or a speed to pulse rate method. = The faster the speed the greater the rate of the RF pulse transmitted. Bill ----- Original Message ----- = From: "Enrico Schuerrer" To: "Microcontroller discussion list - Public." Sent: Tuesday, February 14, 2006 11:40 PM Subject: Re: [EE] Speedometer for the model railroad - RF or IR? -----Urspr=FCngliche Nachricht----- = Von: "Peter van Hoof" An: "Microcontroller discussion list - Public." Gesendet: Mittwoch, 15. Februar 2006 02:16 Betreff: Re: [EE] Speedometer for the model railroad - RF or IR? > > But this is the ADVANTAGE of this solution > Imagine running multiple trains on the track > rail voltage on a section would give rpm's (speed) > on this section. this way different trains could be > running in different sections each with their own > feedback > > furthermore if you did want more than one segment > coupled all you would need is a capacitor between > these sections (the supply for the sections would > go thru a coil and you take the hf off at the rail > side with a capacitor) > I need only to know the speed of one train. Unfortunately the rail voltage = and the speed are a) not linear and b) not absolute (each locomotive has a = different gear). The wiring between the modules is defined so I can't change it (the modules = belong to different people - if I want to change the wiring all other club = members would have to do it in the same way). This was the reason why I am = looking for an independent solution. I have looked onto the different RF solutions and now only have to find a = source here in Austria where to buy. It makes no sense to buy 2 = transmitters/receivers in the USA for $12 and pay $30 for delivery... Due to the fact that there are only pulses with different frequency (from = lets say 0 Hz to 30 Hz) over a RF link it's not clear for me how to code = it... Regards Enrico -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist