it’s a step further than a tool length probe, but the way I’m setting it up would be completely compatible. I recently started working on a 3d touch probe:
for a tool length probe, nothing would change to the code, just an alligator clip on the drill bit and a touch plate instead of the 3d probe. it’s the same type of signal (maybe just inverted), but that’s an easy enough addition if needed.
Unfortunately, it’s not just something you add to the code on a lazy Sunday afternoon. I’ll need a few of those before this project is complete
In the meantime, you can just use a multi-meter and measure the resistance. When it starts beeping, you know the reference point for determining the new Z-height. (measure with the old one and the new bit and calculate the difference)