Stepper Motors

Background

     

28BYJ-48 Stepper Motor & ULN2003 Stepper Motor Driver

Stepper motors are special types of motors used in high-accuracy applications like 3D printers and robotic mechanisms. The 28BYJ-48 is a unipolar stepper motor with 4 phases and 2 coils. It has 2048 different steps in its full 360-degree rotation. It can move at a maximum speed of 12 RPMs It is driven using ULN2003 stepper motor driver chip. This chip requires 4 digital outputs and is typically supplied by an external power source (not Arduino). Below shows the wiring for the two coils. Pulses of different polarities are sent to the coils in a certain sequence to cause the motor to advance step by step.

 

Hardware Description

Pinout

• IN1 - Pin 8
• IN2 - Pin 9
• IN3 - Pin 10
• IN4 - Pin 11
• + – 5V-12V
• - – GND

 

Software Description

• #include <Stepper.h>
  
  • Include library
• Stepper myStepper(STEPS_PER_REV, 8, 10, 9, 11);
  
  • Declares object. (yes, pin order is correct: 8, 10, 9, 11).
• myStepper.setSpeed(speed);
  
  • Set the speed in revolutions per minute.
  • Max value is 12!
• myStepper.step(steps);
  
  • Tell the stepper motor how many steps to move.
  • 2048 is 1 full revolution. 4096 is 2 full revolutions.
  • 107 moves 107 steps in a clockwise direction.
  • -224 moves 224 steps in a counter-clockwise direction
• Delays aren’t necessary. step() waits until the movement is done before moving on to the next line of code.

https://create.arduino.cc/editor/mjdargen_ravens/e2cfa396-b0d7-44de-aea3-b16dd90f208b/preview

 

Resources

• Tutorial: https://learn.adafruit.com/all-about-stepper-motors/
• Arduino Unipolar Stepper Motor Basics: https://docs.arduino.cc/tutorials/generic/unipolar-stepper-motor
• Arduino Stepper Motor Library Tutorial: https://www.arduino.cc/reference/en/libraries/stepper/