This automatic railroad crossing has been used a couple of times at Lego World.
The automatic railroad crossing has flashing lights and sound. The crossing is powered by two PF motors and two infrared receivers: one for controlling the motors, one for controlling the lights.
A Mindstorms NXT is used with HiTechnic IR link as remote control, to make the lights flash and is used for the sound (endless loop of a bell sound).
Post time: Jun-17-2017