Sorted. I put a 10k resisitor in the line and the signal worked fine. I have it linked to the arduino and a relay to switch the power to the track. The signal works well but for some reason the relay doesn't change the power so there is still some work to do.
Long Haired DavidA.K.A. David Penningtonmain man on the Sunset and North Eastern R.R.http://www.gmrblog.co.ukfrom the UK
Hi everyone. I am building a little Arduino circuit to control access to my staging yard. The idea is that I have a signal at the exit of my tiny switching layout on the single exit road into the staging. hen a train gets to the end of the staging track it fires a light sensitive diode which causes the track power to be killed and the signal to turn green. Removing the train from the track into my storage boxes will release the diode which will rest the the track power and the signal will turn green.I bought a Berko signal at a show last week but it doesn't work correctly so I have bought an Atlas 70 000 102 single head common cathode signal. As I am not using the Atlas controller, I need to put a diode in line with the cathode. I would normally use a 220 ohm resistor. What I want to know is - is this value appropriate for running an Atlas signal?