Stepper Motor Smoother Board (Diodes) / Linear Module Pinout?


#1

Snapmaker (or anyone else if you have it?): Can you please provide the pinouts of the linear modules? I can take mine apart and try to reverse engineer it, or you could just tell me. Also, what kind of connector is that on the controller? RJ45?

Reason: I’ve noticed veritcal lines in the walls of my prints that I think might be due to low voltage noise on the stepper motor lines. Another super cheap / low budget Marlin based printer gets around this via an upgrade by installing a diode board inline to each of the X and Y stepper motors. The good diode board has diodes going both directions and makes the board “reversible” so that it doesn’t matter which orientation it is installed in. The diodes provide a minimum voltage to the stepper motors before they start to move and this smooths out the print because low voltage spikes are ignored / prevented from hitting the motors during a print.

If I’m barking up the wrong tree, I certainly don’t mind being educated. Maybe there is something already in the controller.


#2

The connector is a RJ12 (telephone cables use the same). I just know of the pinout from the laser module, because there is an Instructable for the Laser Module

I would suggest (if you have access to it) to watch the signals to the steppers with an DSO and look for the noise in the voltage.


#3

So the head uses same connector as the axis? Thanks. I don’t have my printer here with me right now. So getting information helps me get started anyway.

I have an old o-scope. I might be able to, but putting together a small diode board should be easy as long as I can see which pins need the diodes.


#4

Yeah, the module is an RJ45 (8 pin), and everything else is an RJ12 (6 pin).

Is it a single vertical line in the print? The default print settings will do the vertical step at the same location, creating a single vertical line. You can try playing with the print settings in the “Surface” section, although the various options have some caveats.

Stepper motors are different beasts than normal motors. In theory, noise on the lines shouldn’t matter. But I’m not sure of all the details of a “partial step” movement, so I could be wrong.


#5

My thoughts on this are based on a video comparing the performance of a cheap Ender 3 printer before and after adding a diode board to the steppers. Basically the diode board is filtering out low voltages and creating a (0.7 volt I think) low voltage threshold that must be exceeded for the stepper motors to begin moving. The results in the video speak for themselves on the other printer.

Also, once I learn the pinouts, I’m interested in maybe making a conversion board that will let me convert my controller over to a Duet board for added precision, lower noise steppers, network control, and more. The Snapmaker controller is about as bare as it gets. The cost of the unit is weighted more towards the rigid base, large aluminum extrusions, touch screens… all great things. Where it is weak (in my opinion) is the controller and the hot end / cold end. I’d like to upgrade mine to the point where it can really shine. (I get good prints off the Snapmaker, but I think I could get fantastic prints with a better hot end, better cold end, remote drive direct extruder (zesty nimble), and a better controller with trinamic drivers.)