would this idea work in theory? attached jpeg the relay is normally closed, when current goes through poles 1 and 2 poles 3 and 4 open. i know this wont work as is because the micro-controller will shut off and it will never leave the station. but im sure you could add a timer circuit.
and another totally unrelated question:
for the $50 robot, the resistor that should be 340ohms, i only have 140ohms now. could i use two or even one in series?