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RPI4 GPIO driven focuser driver

  • Posts: 87
  • Thank you received: 12
Hi guys

Here's a version of focuser I've made with a DC breakout board, somehow "built-in" in a RPI box.
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, for powering up both the PI and stepper breakout - As the motor requires a 12v to operate.
2. I got a tiny 12V-5V step down breakout for an integrated power source. The 5V feeds to the GPIO 5V input pin for powering up the RPI4. While I split one wire from the 12V input to the +ve power feed at the DC stepper board, allowing the 12V to feed to the motor unit
3. I've a got the TB6612FNG breakout for driving the motor. Note this is a DC driver board. I check the pins and I solder one side with Dupont joints, allowing the breakout to plug into the GPIO pins directly.
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.

I think a similar setup can be done for stepper breakout board and motor. Yet the heat problem on the breakout board would requires some attention and further modifications.


Arduino version:
Last edit: 1 year 10 months ago by Stephen Wong.
1 year 10 months ago #69334

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  • Posts: 149
  • Thank you received: 28
Hi sywong2000, great job.

I did a similar thing a while ago, but not a neat as you build. But i also added a small fan which keeps the rpi4 cpu temp in check.

See images.

Takahashi FC-100DF refractor
ZWO ASI 071 imaging camera
ZWO ASI 120MM on 30mm guidescope
Skywatcher HEQ5 Pro mount with belt drive
Raspberry Pi 4 running Ubuntu 22.04LTS headless with KStars/indi
The following user(s) said Thank You: Stephen Wong
1 year 10 months ago #69400

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