PBL3775 Wiring for Moppy?

[MuffyTarkin]

Hey, I stumbled into this when researching this driver chip for use with Arduino. I have a ScanJet 5100c with the same driver powering the motor and I'd like to interface directly with this driver by using Moppy (sends step signals to a driver to make it pulse at frequencies to generate musical notes). However, it seems this particular project was designed with a multitude of pins in mind. Moppy only uses two outputs, step and direction.

As far as I can gather, DIS1 and 2 are for stepping (pulsing the windings) while PHASE1 and 2 is for direction, but my knowledge of motors is limited to working with simple, pre labeled drivers. I already have this scanner working for my desired purpose but I have a feeling the external driver I'm using is a bit too much for this motor (lots of undesired side effects in terms of noise). I figure if I could use the actual driver and circuit designed with this exact motor in mind I'll have much better results, I'm just having trouble figuring out how to take the 6 pins required here and condense them into the 2 that Moppy uses. Well, technically 3 as the driver still needs to be on the same ground as the Arduino.

On my external driver, I had DIR-, PUL-, and EN- all running to the Arduino ground, and PUL+ and DIR+ running to the respective step and direction pin output from Moppy. If I had an idea of what pins on this PBL chip corresponded to on my external driver I'd have a much easier time hooking it up. I'm sure it's a simple matter of running VRef2, DIS2, and perhaps PHASE2 all to the Arduino ground and hooking DIS1 and PHASE1 into the step and direction pins (or the inverse of all of these), but like I said, my knowledge of motors is super limited and I can't make heads or tails of what the differences are between DIS1/DIS2 etc. I wanted to check with someone smarter than I am first. I've destroyed a number of Arduinos already from clueless plugging and playing.

If you have any thoughts I'd greatly appreciate it!

[Francien99]

Hi there MuffyTarkin,

If I understand you correctly, you are trying to make music with a stepper motor.
I have never used Moppy (is this the moppy you are talking about: https://github.com/SammyIAm/Moppy) ?
And instead of a floppy disk you are trying to use the stepper motor of a scanner.
You have got the stepper connected to an Arduino with an external driver, but this has undesired side effects.

First thing that comes to my mind, is that my stepper is less noisy then a floppy disk. At the same time, a 3D printer can sound a bit "musical", when certain shapes are being printed, so that could be interesting... who knows, in the future current 3D printers (with 3 stepper motors) will be as old and obsolete as scanners are nowdays and people will use the for music only! ;-)
I would like to hear the result once you get it working :-).

Sounds like you need the most easy solution, so I will assume "full step mode" only is the best solution for you (this is the most easy option, requires the least amount of wires and the motor makes the most noise).

I have used six pins, because the driver needs them. The 6 pins Phase1, Phase2, Dis1 (=disable1), Dis2, VRef 1 and VRef 2 are all related to making the stepper motor rotate.
However, VRef 1 and VRef 1 are always HIGH, I just added them to my code to be able to add the "modified half step mode" in the future. I suspect you could just as well connect both to 5V, however I have not tried that yet.
If you don't need "half step mode", Dis1 and Dis2 are always LOW. I suspect you could just as well connect both to ground, however I have not tried that yet. Try both at your own risk.
This leaves you with two wires to connect: Phase1 and Phase2. The bad news is: all these wires are for stepping, there is no seperate wire for direction, nor for "take one step".
I can't say anything about the other driver you are using. Do you have a datasheet or something of that driver?

Connecting VRef2, DIS2, and perhaps PHASE2 all to the Arduino ground does not sound like a good idea to me. A stepper has got two (sets of) spools on the inside: Phase1, Dis1 and VRef1 all operate one spool, Phase2, Dis2 and VRef2 all operate the other one.

I hope this does help a little.

[MuffyTarkin]

Hey! Yeah, that's the Moppy I'm referring to. I've already gotten the scanner working with an external driver. I can't find the exact one I have, but this one is extremely similar.

I'm interested in trying to use the driver on the board because obviously, the circuitry there was specifically tailored to function with this particular motor. My musical scanner sounds like a dying elephant when compared to pretty much any video out there that has a musical scanner. Here's a link for an example. Even this scanner, provided you leave all the internals hooked up, sounds infinitely better when put into the maintenance test (the one that makes it play Ode to Joy). So I know it's not a motor problem, I probably have the wrong driver for this motor or it's too powerful for it.

This has been useful information though, perhaps I can use this driver chip to power other motors in the future for non-musical applications.

[Francien99]

Hey!
I did not know about that 'Ode to Joy' easteregg. Just tried it and it worked :-). Lol, thx for the tip!
The scanner makes way more sounds this way, then it did when I moved just the stepper (I had the belt that moves the printer head removed trying out my code).