I have an MP3DP-V2. It has been modified significantly and while it still works fine it is primarily a test bed for different things I’d like to mess around with.
Currently it has an MKS Sbase v1.3 control board running Klipper and a BL Touch probe for Z min. However I’m in the process of evaluating different extruders and would like to switch to a BTT Microprobe to save some space on the print head.
I have the control pin configured properly and it deploys and stows fine.
I think I have the sense pin configured properly: ^! (pull-up and inverted) but the triggered state is not being detected.
When deployed the voltage at the sense pin is 3.3V as expected, however when retracted by probe_stow or after touching the pin and mechanically triggering it, the sense pin voltage drops, but only to 2.2V - not close enough to zero to be electrically identified as low.
The Z-Max limit switch header I am using has +5V, GND & S which I am using for the Red (3P 5V)/Black (2P GND)/White (2P Probe) wires from the probe. The Orange (Servo/Control) wire and other Black (3P GND) wires go to the EXT headers.
I’ve seen a bunch of posts that warn you need a “strong pull-up”, but its almost like it is too strong - the BTT closure does not drain enough: I have tried shorting the S pin to GND and I do get a “Triggered” state that way at 0V.
I’ve tried not requesting the internal pull-up but the behavior appears to be the same. Could I have an issue with the two grounds not being on the same loop or something?
I do have a SKR Pro v1.2 that I pulled for a Jackpot upgrade on my MPCNC, but don’t really want to embark on rewiring the whole printer if I don’t have to - I more likely to just put a mechanical limit switch off to the side somewhere and live with mechanical bed adjustments / leveling.
I suppose I could flash the SKR with Klipper and connect just the Microprobe to see if it registers okay there - perhaps I got a bad microprobe or screwed it up somehow. Any other thoughts?
Thanks for the confirmation that it works fine on an SKR Pro 1.2.
I should probably just pull the trigger and swap out the MKS Sbase board I am using - it doesn’t have a convenient header so I pulled all of the female pins from 2P and 3P housings and put them into singles which run to three different places on the board. I don’t have any other plans for my SKR, but I was hoping to avoid the wiring headache. It really shouldn’t be too bad, but I suspect I’ll find a couple cables that are too short to reach the header locations on the SKR. Also, my current wiring while functional is kind-of sloppy and I’m sure if I change the control board I will spend a bunch of time cleaning that up while I’m at it.
I am leaning toward flashing the SKR with klipper and building and hooking up just the microprobe. If the one I have in hand works fine, I’ll burn a few hours playing with pull-ups on the MKS until I get frustrated and crass enough to “accidentally” short it out and force the swap.
If the Microprobe doesn’t work on the SKR, I’ll have to decide if I should order another one or abandon. They are cheap enough, but I have a tendency to fill my cart with other random stuff when I’m placing an order, and my junk drawer is already overflowing…
FYI: without your drive voltage hooked up (12 or 24V), If you power the board with just USB like sometimes we I do to check the firmware version or verify end stops, it will not work on the SKR. The SKR will boot cycle with red light flashing if the BTT microprobe servo is connected. the USB cannot power the servo that pushes the pin in and out for initialization. I thought the board was toast and then that the probe was bad, but it was just browning out because USB can’t push enough amperage to initialize the probe. Not to worry… it is a feature.
Thanks, that will help make sure I don’t blame the Microprobe unecessarily.
I should have a chance to try later today. If I figure anything out I’ll post for future reference.
