Hello. I'm trying to set up a probe that will allow me to engrave wood that has a contour to it. GCode Ripper looks like it will work for my needs. The guy in the video demonstrates how it works. I've built a little homemade probe. However, I'm having issues getting it to work. When I hook it up, I can't get the "Digitize" light to flash on and off like the man in the video does. I've set everything up to mirror his from what I can tell. Any suggestions on something I may be missing? Thanks!