My astronomy project:
Stepper motor focus driver

Content:

1. Collecting information
2. Hardware tools for development
3. Arduino Nano and DRV 8825
4. Prototype setup
5. Setup Arduino system
6. Schematic / setup
7. Start assembling circuit board
8. Setup INDI for MyFocuserPro2
9. Enclosure
10. 5 kg load test
11. High impedance stepper motor
12. To be continued

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

4, Prototype setup:

Before I built the electronics on the circuit board I do a prototype setup to test that my ideas work, it isn't exactly as the original construction.

The lab board with most of the components installed. The black/red cable in background is the 12 volt power to the stepper motor. To the right the NEMA 17 stepper motor installed on my special built 3" focuser.

The prototype board with a lot of wires. To the right, the USB connection which deliver the 5 Volt power. When connected, no smoke !

The four wires that power the stepper motor two coils. Its a bipolar stepper motor. The wire pairs are twisted to reduce the electric noise. special built 3" focuser with a Push Pull design. You can read more about it here: 3D-printed Push Pull focuser.