Hi guys

Here's the version I've made with a DC breakout board.
The focuser I have is with the same model as the Orion AccuFocus.
But I'm sure the same idea can be applied to stepper version with a similar setup.

What I did:
1. Add a DC jack for feeding 12V and power both the PI and stepper breakout. As the motor requires a 12v to operate.DC breakout. The DC motor requires 
2. I got a tiny 12V-5V step down breakout for an integrated power source. The 5V feeds to the GPIO pin for powering up the RPI4. While I split one wire from the 12V input to the +ve power feed at the DC stepper, allowing it to feed the 12V to the motor
3. I've a TB6612FNG for driving the motor. I check the pins and I solder one side with dupont joints, allowing the breakout to plug into the GPIO pins.
4. The original focuser uses a RJ10 cable and socket for connecting between the controller and the motor. I reuse the same way so I get a RJ10 jack and connect to the output pins of the DC driver board.
5. You can also see I have a RTC breakout that allows the RPI to have a real time clock.
6. Source code of the driver here: github.com/sywong2000/indi-gpio_pwm_focus

This setup gives me the advantage of:

1. a compact package connecting to the motor. Do not need an intermediate motor controller box.
2. a single 12V that feeds the PI box and the motor.

Yet the heat problem on the motor breakout for stepper driver would requires some attention.