Rotator control with stepper motor HAT/shield from Adafruit?


#1

Hello!

Is it possible to use the stepper motor HAT for the raspberry pi 3, instead of the arduino pro mini + custom pcb + stepper drivers?

I couldn’t find a conclusive answer as to why not, or if anyone has attempted this.

Which part of the observer code do you need to modify to make it “shield friendly”?

Any help is much appreciated!

Thank you,
-Andrew


#2

@jafo117 there is no reason it shouldn’t work. AFAIK there has been no one who tried (+documented) such a setup. The drivers on that board are similarly-rated to the A4988 driver chips.

The software driver for the board should listen on a TCP port for commands to emulate a rotctld process. Current usage of the rotator communications between satnogs-client and the rotator is two commands. See the code that sends commands to the rotctld port. I’m not sure off hand what else rotctld does with the attached rotator controller.

All of the above assumes whatever is being send position commands is also able to keep track of its own position in order to act accordingly. This is where the homing switch and the encoder come in. This functionality and hardware interface would need to be included in such a build, the Adafruit HAT handles motor driving only.


#3

Plz drop a line if it works. Sounds interesting.


#4

Has anyone managed to get this to work? I was going to try to control my stepper motors with an SB Motor Shield.


#5

FYI - I am planning to use a Raspberry Pi and Adafruit Motor Hat combo. I have learned that the Adafruit driver does not do current limiting, which is what the Pololu part does, so I will be using stepper motors that are spec’d for 12 V drive (as opposed to 1 A current drive). It seems simple (Ohm’s law), but it gets complex finding the right motor to go with the right driver. I’ll post back once I get the motors working.