Using a stepper for probe deploy

General Discussion
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Hey folks!
After upgrading my printer with a housing i got problems with my self-build servo driven optical z-probe. The cheap servo motors you can get from china don’t like the temperatures… :wink: Furthermore the 120°C bed also makes lot of heat…
Yes i could buy something but i wanna build a new probe for my own. Smaller and less weight… the plan is to use a mini stepper motor you can find in dvd drives or something. I have one with about 5g weight. For the probe i use a small carbon needle. Case would be printed with greentec pro carbon.

But before i start building i search for the software parts… but I can’t find anything about how I can use a stepper motor in the probe macro instead of a servo. Is that possible? Maybe i can “home” the extra stepper using the optical switch i use for probing. If thats not possible maybe i can ignore the exact position and build the mechanism with tolerance to strip in every direction… but at this point i simply can’t find information if its possible at all.

In theory i define a new stepper in printer.cfg with pins mapped to my raspberry for step and dir. After that i can write new macros for activation and deactivation.

SET_STEPPER STEPPER=stepper_extra STEPPER_ENABLE=1
G1 E10 F3000
SET_STEPPER STEPPER=stepper_extra STEPPER_ENABLE=0

Did an extra stepper also need homing? Or can i deactivate that? Help would be great, sry for my english - I’m out of practice. :smiley:

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Hello @lichtblick !

On that part: Yes. The stepper has to be in a defined position.

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I also found that if you leave out the endstop pin, it doesn’t need homing. I can construct in such a way that I don’t need an exact position.
If that has to be in the config in any case, it would be necessary to home the probe stepper before testing. Can I then use the endstop for z - i.e. then use it for two things?

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Play around a little an found manual_stepper - these ones aren’t connected to the printer cinematics. Great! I got it to control the mini steppers from the dvd drive with my arduino directly. I think i need a driver like A4988 to control the stepper with klipper. Another option should be to write a phyton script and control it with the raspberry directly…

Great detail with the micro stepper - they have not a lot of force - in the construction for the probe i’ll let it run against a “wall” - no need for homing :wink:

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