Arduino Stepper motor Control

Stepper motors fall somewhere in between a regular DC motor and a servo motor. They have the advantage that they can be positioned accurately, moved forward or backwards one 'step' at a time, but they can also rotate continuously.

The stepper motor has five leads, and we will be using both halves of the L293D this time. This means that there are a lot of connections to make on the breadboard.

The motor has a 5-way socket on the end. Push jumper wires into the sockets to allow the motor to be connected to the breadboard.

Note that the red lead of the Stepper motor is not connected to anything.

The following sketch uses the Serial Monitor, so once the sketch is installed and running, open the Serial Monitor and enter a number of 'steps'. Try a value of about 500, this should cause the motor to turn through about 360 degrees. Enter -500 and it will turn back in the reverse direction.

Code

#include <Stepper.h>

int in1Pin = 12;

int in2Pin = 11;

int in3Pin = 10;

int in4Pin = 9;

Stepper motor(768, in1Pin, in2Pin, in3Pin, in4Pin);  

void setup()

{

  pinMode(in1Pin, OUTPUT);

  pinMode(in2Pin, OUTPUT);

  pinMode(in3Pin, OUTPUT);

  pinMode(in4Pin, OUTPUT);

  // this line is for Leonardo's, it delays the serial interface

  // until the terminal window is opened

  while (!Serial);

  

  Serial.begin(9600);

  motor.setSpeed(20);

}

void loop()

{

  if (Serial.available())

  {

    int steps = Serial.parseInt();

    motor.step(steps);

  }

}

In this tutorial, we do not use the common Red connection. This connection is only provided if you are using a different type of drive circuit that does not allow the current in each coil to be reversed. Having a center connection to each coil means that you can either energise the left or right side of the coil, and get the effect of reversing the current flow without having to use a circuit that can reverse the current.

Since we are using a L293D that is very good at reversing the current, we do not need this common connection, we can supply current in either direction to the whole of each of the coils.