Control of a stepper motor for a "Barn Door Tracker"
Full step mode
| GPIO17 | GPIO18 | GPIO22 | GPIO27 |
|---|---|---|---|
| A- | B- | A+ | B+ |
| 0 | 0 | 0 | 1 |
| 0 | 0 | 1 | 0 |
| 0 | 1 | 0 | 0 |
| 1 | 0 | 0 | 0 |
Half step mode (slighly quieter than full step mode)
| GPIO17 | GPIO18 | GPIO22 | GPIO27 |
|---|---|---|---|
| A- | B- | A+ | B+ |
| 0 | 0 | 0 | 1 |
| 0 | 0 | 1 | 1 |
| 0 | 0 | 1 | 0 |
| 0 | 1 | 1 | 0 |
| 0 | 1 | 0 | 0 |
| 1 | 1 | 0 | 0 |
| 1 | 0 | 0 | 0 |
| 1 | 0 | 0 | 1 |
To reverse the direction, just reverse the direction of iteration through the table
Wiring
- RED = Coil A+
- BLUE = Coil A-
- WHITE = Coil B+
- YELLOW = Coil B-
Should a higher voltage be required for driving the stepper motor, it would be applied to pin 8 of L293D chip, instead of 5v.
Usage In one terminal window, start the service on default port 5000:
python3 ./StarTracker.py
In a second terminal type one of commands without curly braces:
wget -o /dev/null http://127.0.0.1:5000/{start|stop|pause|resume|faster|slower|reverse}
Alternatively connect to a web browser to URL:
http://0.0.0.0:5000/tracker