Breadboard Adapter for Lego Mindstorms to control bipolar stepper motor

All, I am bit of a novice and I am trying to design and build a very slow moving camera platform for astrophotography. Before I start buying some of the components, I want to understand whether my idea will work. I want to control with microstepping a strong bi-polar stepper motor using a pololu motor driver. I want to use the EV3 via the Breadboard Adapter for Lego Mindstorms to act as micro controller. Did anyone try this? I see lots of reference of using the lego motors in other systems and making new sensors for the EV3, but I have difficulty finding any references for my project.

The questions I have are:

  1. will this work
  2. do I need any special EV3 program blocks or can I use standard motor blocks (will the EV3 recognize these?)
  3. are there other EV3 program blocks I can use to directly communicate with the motor driver via the I2C protocol.

Thanks a lot for your help.

Hey Jeroen,

Do you have a diagram for a specific part you’re trying to use? I guess the devil is in the details on this sort of project!

It sounds like an awesome project!

Hi John, thanks for coming back so quickly. Yes indeed an awesome project. Basically I am aiming to build this: for a fraction of the costs and enjoying the project time with my son whilst building and using it!

I am aiming to drive one of these motors (undecided): Nema 17, 200 step, 1.7 amp per phase Nema 17, 400 step, 1.7 amp per phase Nema 23, 200 step, 2 amp per phase

using a vertical shaft worm gear with a gear ratio of 30:1, 120:1 180:1 or 360:1 (again to be decided depending on motor power and internal friction…working that)

To get basically to one revolution per astronomical day. The motor will be running somewhere between 4 and 12 minutes per revolution. So micro stepping is important and smooth operation is everything as a jerking motion will spoil the pictures!

As motor driver I am looking at the following options (see hook up schemes attached). The choice will be determined by whether we think we can get this to work. I can also chicken out and not risk it and just buy an arduino, but that is the last resort.
adafruit TB6612FNG
Big_easy_driver_HookupFixed available via spark fun
Pololu DRV 8825

and the EV3 connected up via the dexter break out board. At the moment I am thinking of using the 4.3V line to power the motor board, have a separate 12 V motor supply and I am hoping that I can use the SCL and SDA ports as the 2 interface boards as per the simplified connection schemes attached to this post for step and dir.

So would this all work and would the EV3 see this as a motor or do I need to build a dedicated I/O block.

As you can see I did my research but I am really reaching the limit of my understanding of electronics here…thanks for the effort and help.