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https://github.com/IDWizard/uln2003
Micropython code to drive stepper motors via ULN2003
https://github.com/IDWizard/uln2003
Last synced: 3 months ago
JSON representation
Micropython code to drive stepper motors via ULN2003
- Host: GitHub
- URL: https://github.com/IDWizard/uln2003
- Owner: IDWizard
- License: mit
- Created: 2017-07-29T19:00:22.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2017-07-29T19:35:48.000Z (over 7 years ago)
- Last Synced: 2024-04-22T12:35:37.881Z (7 months ago)
- Language: Python
- Size: 3.91 KB
- Stars: 43
- Watchers: 0
- Forks: 16
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-micropython - uln2003 - Driver for 5V 28BYJ-48 stepper motors. (Libraries / Motion)
- awesome-microbit-zh - ULN2003 - 通过ULN2003达林顿晶体管阵列来驱动步进电机的Micropython代码。 (编程 / Python)
README
# uln2003
Micropython code to drive stepper motors via ULN2003
This is the ongoing work of my experiments with the BBC micro:bit and some ULN2003 stepper motors connected to 5V 28BYJ-48 Stepper Motors.
## Materials
You will need:
1. A micro:bit with USB cable (and a computer to connect it to!)
1. A 5V DC power source
1. One or more 28BYJ-48 stepper motors with matching ULN2003 driver boards
1. Wires, lots of wires.
1. (Optional but handy) A breakout board to make accessing the bit's IO pins easier
## Wiring / Connecting
1. Plug the stepper motor into the ULN2003
1. Connect the 4 pins from the ULN2003 into 4 separate I/O pins of the bit
1. Connect the 5v input +/- on the ULN2003 to a 5v source +/- terminals
1. Connect the bit to the computer
1. Load up the library and push to the bit (i.e. compile the program and upload to the bit)
## Using the library
Code example:
```python
# Create a stepper using the HALF_STEP command sequence
# to a stepper which is connected:
# micro:bit ULN2003
# pin16 -> INP1
# pin15 -> INP2
# pin14 -> INP3
# pin13 -> INP4
# Set the delay between steps to 5 microseconds
s1 = Stepper(HALF_STEP, microbit.pin16, microbit.pin15, microbit.pin14, microbit.pin13, delay=5)
s1.step(100) # Rotate 100 steps clockwise
s1.step(100, -1) # Rotate 100 steps anti-clockwise
```
A delay of less than 5 microseconds may cause the motor to simply buzz and not move at all. Try and see what works for you and your motors.
Because of the gearing of this motor a full rotation isn't very exact. It is somewhere between 508 and 509 steps. The constant FULL_ROTATION has a value of int(4075.7728395061727 / 8) = ~509 steps.
## Advanced Usage (Driving more than 1 stepper motor)
Being able to drive a stepper is cool but the bit has a lot more IO pins. It's possible to drive two steppers:
```python
s1 = Stepper(HALF_STEP, microbit.pin16, microbit.pin15, microbit.pin14, microbit.pin13, delay=5)
s2 = Stepper(HALF_STEP, microbit.pin6, microbit.pin5, microbit.pin4, microbit.pin3, delay=5)
s1.step(FULL_ROTATION)
s2.step(FULL_ROTATION)
```
But you will notice that this makes stepper1 move a full circle (or a teensy bit more than a full circle) and then stepper2 will move a full circle.
If you want to move both motors at the same time then you need to interleave the commands to do that so that stepper1 moves a step, then stepper2 moves a step, then stepper1 moves a step and so on.
The library provides a way to do that:
```python
s1 = Stepper(HALF_STEP, microbit.pin16, microbit.pin15, microbit.pin14, microbit.pin13, delay=5)
s2 = Stepper(HALF_STEP, microbit.pin6, microbit.pin5, microbit.pin4, microbit.pin3, delay=5)
c1 = Command(s1, FULL_ROTATION) # Go all the way round
c2 = Command(s2, FULL_ROTATION/2, -1) # Go halfway round, backwards
runner = Driver()
runner.run([c1, c2])
```
The Driver class will run 1 step from each command until there are no more commands to run which will make the two motors move (apparently) simultaneously.