Stepper Motor Control with Potentiometer

 Stepper motor control with a potentiometer can be useful. Typically the stepper motor movement are controlled with programs and usually are programmed to do repeated predefined movement for automation. On the other hand, stepper motor control with potentiometer is manual. This type of stepper motor control is also important in many application. Earlier it was shown how to control a servo motor with potentiometer. Here it is illustrated how one can control a Nema 17 stepper motor using pontentiometer. The example is part of my bluetooth controlled arduino car which I wanted to modify into a crane.

Program code for Stepper Motor Control with Potentiometer

#include <AccelStepper.h>

// Stepper motor pin definitions
#define X_STEP_PIN 54
#define X_DIR_PIN 55
#define X_ENABLE_PIN 38
#define X_CS_PIN  53
#define T2 14  // Analog Input

// Initialize the stepper motor
AccelStepper stepper(AccelStepper::DRIVER, X_STEP_PIN, X_DIR_PIN);

void setup() {
  Serial.begin(9600); // Initialize serial port for debugging.
  pinMode(T2, INPUT); // configure to control stepper motor

  // Initialize stepper motor
  pinMode(X_ENABLE_PIN, OUTPUT);
  digitalWrite(X_ENABLE_PIN, LOW); // Enable the stepper driver
  stepper.setMaxSpeed(1000); // Set maximum speed for the stepper motor
  stepper.setAcceleration(500); // Set acceleration for the stepper motor

  // Test stepper motor by moving 180 degrees
  int stepsPerRevolution = 200; // Number of steps per revolution for your stepper motor
  int stepsFor180Degrees = stepsPerRevolution / 2; // Calculate steps for 180 degrees
  Serial.println("Testing Stepper Motor");
  stepper.moveTo(stepsFor180Degrees); // Move 180 degrees
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }
  delay(1000); // Wait for a moment
  stepper.moveTo(0); // Move back to the original position
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }
}

void loop() {
  int potValue = analogRead(T2); // Read potentiometer value
  int stepperPosition = map(potValue, 0, 1023, 0, 200); // Map potentiometer value to stepper position range (0 to 200)
  stepper.moveTo(stepperPosition);

  // Step the motor
  stepper.run();

  delay(100); // Delay for a short period before the next reading
}

1. Include AccelStepper Library

#include <AccelStepper.h>

The code starts by including the AccelStepper library, which simplifies controlling stepper motors with Arduino. This library provides advanced features for controlling stepper motors, such as acceleration and deceleration control.

2. Stepper Motor Pin Definitions

cpp
// Stepper motor pin definitions
#define X_STEP_PIN 54
#define X_DIR_PIN 55
#define X_ENABLE_PIN 38
#define X_CS_PIN  53
#define T2 14  // Analog Input

• X_STEP_PIN (Pin 54): Controls the steps of the stepper motor.
• X_DIR_PIN (Pin 55): Controls the direction of the stepper motor.
• X_ENABLE_PIN (Pin 38): Enables the stepper motor driver.
• X_CS_PIN (Pin 53): Typically used for chip select in certain applications; not used in this example.
• T2 (Pin 14): Analog input pin connected to a potentiometer for reading its value.

3. Initialize the Stepper Motor

AccelStepper stepper(AccelStepper::DRIVER, X_STEP_PIN, X_DIR_PIN);

 This line initializes the stepper motor object using the AccelStepper library. The DRIVER option indicates that the stepper motor is being controlled via a driver that requires step and direction inputs.

4. Setup Function

void setup() {
  Serial.begin(9600); // Initialize serial port for debugging.
  pinMode(T2, INPUT); // Configure to control stepper motor

Serial.begin(9600): Initializes the serial communication at 9600 baud rate, which is useful for debugging and monitoring values in the Serial Monitor.
pinMode(T2, INPUT): Sets the pin connected to the potentiometer as an input to read analog values.

5. Initialize Stepper Motor

  // Initialize stepper motor
  pinMode(X_ENABLE_PIN, OUTPUT);
  digitalWrite(X_ENABLE_PIN, LOW); // Enable the stepper driver
  stepper.setMaxSpeed(1000); // Set maximum speed for the stepper motor
  stepper.setAcceleration(500); // Set acceleration for the stepper motor

pinMode(X_ENABLE_PIN, OUTPUT): Configures the enable pin for the stepper motor driver as an output.
digitalWrite(X_ENABLE_PIN, LOW): Activates the stepper motor driver by setting the enable pin to LOW (active low configuration).
stepper.setMaxSpeed(1000): Sets the maximum speed for the stepper motor in steps per second.
stepper.setAcceleration(500): Sets the acceleration for the stepper motor in steps per second squared.

6. Test Stepper Motor by Moving 180 Degrees

  // Test stepper motor by moving 180 degrees
  int stepsPerRevolution = 200; // Number of steps per revolution for your stepper motor
  int stepsFor180Degrees = stepsPerRevolution / 2; // Calculate steps for 180 degrees
  Serial.println("Testing Stepper Motor");
  stepper.moveTo(stepsFor180Degrees); // Move 180 degrees
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }
  delay(1000); // Wait for a moment
  stepper.moveTo(0); // Move back to the original position
  while (stepper.distanceToGo() != 0) {
    stepper.run();
  }
}

7. Loop Function

void loop() {
  int potValue = analogRead(T2); // Read potentiometer value
  int stepperPosition = map(potValue, 0, 1023, 0, 200); // Map potentiometer value to stepper position range (0 to 200)
  stepper.moveTo(stepperPosition);

  // Step the motor
  stepper.run();

  delay(100); // Delay for a short period before the next reading
}

 Summary