A fairly simple train detector using ambient light and a photocell,

This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by either 6 or 12 volts - BE SURE to use the proper relay; note that some relays are rated for 5 volts, these should be okay with 6 volts.

copyright 1995-99 MLRollins