I have just bought a 3 wire (5v, ground, signal) touch probe, which I plan to connect to a free pin on my CNC breakout board. I want to configure the probe to find the edge in X and Y of my workpiece or my workpiece holder (back left as you look into the machine). Can anyone recommend and post a simple script to me?

Most 3 wire probes are normally open when they touch the material, the signal pin is pulled low or high depending on your board.