Thanks stirling, enjoy your tea / Jin
It is strange because I used the same BOB and drivers / motors before and I had the probe working well with the same script / wiring as when I started this thread (black to clip and 5V with a resistor in between, red to pin 15).
You'll just have to trust me on this. That is NOT the way to wire a tool for tool setting probe. If you say it worked then OK but it was by some strange quirk of luck that somehow your tool was isolated from ground. That is the ONLY way that could have "worked".
You don't have to trust me on the script though because after we get your touch off working I'll explain exactly why that script is a crock o' horse sh**.
Anyway - the diagram you just posted demonstrates nicely how to do things properly but as I've tried to explain - you have a problem trying to do that with YOUR BOB because the muppets that designed it, HARDWIRED pullDOWN resistors on the dedicated inputs.
See the 10K pullUP resistor on this diagram?
See the that the tool is clipped to GROUND?
See the pullDOWN on YOUR schematic?
See the tool connected to 5V on yours (albeit through a stupid series resistor who's only purpose is to stop a short if the tool actually IS connected to ground).
exactly as I've been trying to explain to you.
Compare it to your BOB manual (page 11) and hopefully you'll see the difference.
All we can try to do on your BOB is try to "over-power" your pullDOWN with a strong pullUP.
So please follow the above diagram EXACTLY except use your 120 ohm resistor instead of the 10K one in the diagram.
Then go to ports n pins and change your probe pin from 8 to 15. Leave it active low (green tick).
Then touch your plate to the tool and you should be good.