Decoder for 4 relays. Used to switch on/off tracks in the shadow station, to ensure parked trains don't consume power. Small resistors allow the flowing of a small amount of current to detect if tracks are being occupied.
This my first take on an Arduino Nano PLC(ish) device.
It uses standard discrete components and thus is rather cheap to build.
But discrete components do take up a bit more space.
The inputs can accept up to 24v and are connected to the analoge pins, using optocouplers the inputs are electrically isolated
from the Arduino.
The outputs uses relays, the outputs from the relay uses an external sourc...