I'm wiring an enclosed control box and would like an indicator when i plug my usb in to my arduino and connect to the grbl firmware. I'd like to run a 24v led powered off of a relay from the arduino. Is there a code that I can use in the Grbl config that sets a pin high (send 5v to the relay) once connected to the grbl through grbl panel? I'm now seeing that you can set start up commands through $n in grbl. Is this a route that I can take? If so, can anyone help with the syntax I would use if I'd like to use pin 1 or pin 11 since I won't be using PWM control on the spindle? Thanks.