Tally Light System For Tricaster

Would it be possible to use an Arduino as a Tally light controller for the TriCaster? I would need it to sense power from the Tally port and then act as a switch to connect two wires from the tally on the camera monitor.

Why not just use the tally output directly to drive a relay/transistor etc - straight across the camera tally inputs?
Arduino seems like the long hard way to perform a simple function unless you’re doing other things with the tally contacts.