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I have put together the following code to activate a motor using an Arduino Uno via push buttons.

  • Two push buttons should be pressed simultaneously to activate the motor for a specified number of steps,
  • then when both buttons are pressed again the motor will spin in reverse, returning the motor to its original position.

The code works, but not every time the button is pressed. I've gone through every line of the code and can't seem to find the issue. I know that the connections are correct since the code executes sometimes, but I don't know if there is an error in the code causing the unreliable response or if I have faulty/cheap push buttons with bad connections.

    #include <Bounce2.h> // Include the Bounce2 library
    
    // Define stepper motor connections:
    #define dirPin 3
    #define stepPin 2
    #define motorEnablePin 4 // Motor driver's enable pin
    #define buttonPin 8 // Push button connected to pin 8
    #define buttonPin2 9 // Push button connected to pin 8
    
    boolean motorRunning = false; // Flag to track motor rotation
    boolean oddRotation = true; // Flag to track odd/even rotations
    
    // Create a Bounce object for the button
    Bounce debouncer1 = Bounce(); 
    Bounce debouncer2 = Bounce();
    
    void setup() {
      // Declare pins as output or input:
      pinMode(stepPin, OUTPUT);
      pinMode(dirPin, OUTPUT);
      pinMode(motorEnablePin, OUTPUT); // Enable pin as output
      pinMode(buttonPin, INPUT_PULLUP); // Use internal pull-up resistor for the button
      pinMode(buttonPin2, INPUT_PULLUP); // Use internal pull-up resistor for the button
      digitalWrite(dirPin, LOW); // Set the spinning direction CW/CCW
      digitalWrite(motorEnablePin, HIGH); // Disable motor driver initially
    
      // Attach the debouncer to the button pin
      debouncer1.attach(buttonPin);
      debouncer2.attach(buttonPin2);
      debouncer1.interval(50); // Set debounce time
      debouncer2.interval(50);
    }
    
    void loop() {
      // Update the debouncer
      debouncer1.update();
      debouncer2.update();
    
      if (debouncer1.fell() && debouncer2.fell()) {
        // Button pressed and motor is not running, initiate motor rotation
        motorRunning = true;
        oddRotation = !oddRotation; // Toggle the rotation direction
        
        int stepsPerRevolution = 200; // Number of steps for one full revolution
        int desiredRevolutions = 10;  // Number of desired revolutions
        int totalSteps = stepsPerRevolution * desiredRevolutions;
        int stepCount = 0; // Counter for the steps taken
        
        // Set the motor rotation direction
        digitalWrite(dirPin, oddRotation ? LOW : HIGH);
    
        // Enable the motor driver
        digitalWrite(motorEnablePin, LOW);
    
        while (stepCount < totalSteps) {
          // Rotate the motor
          digitalWrite(stepPin, HIGH);
          delayMicroseconds(600);
          digitalWrite(stepPin, LOW);
          delayMicroseconds(600);
          
          stepCount++;
    
          // If the desired number of rotations is reached, stop the motor
          if (stepCount >= totalSteps) {
            // Disable the motor driver
            digitalWrite(stepPin, LOW);
            digitalWrite(motorEnablePin, HIGH);
    
            // Reset the flag to stop motor rotation
            motorRunning = false;
          }
        }
    
        // Disable the motor driver when idle
        digitalWrite(motorEnablePin, HIGH);
      }
    }

1 Answer 1

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Bounce.fell() returns true only if the input fell since the last update(). So your code will only work if both buttons are pressed at exactly the same time.

I suggest that you record the time at which each button is pressed and execute your code if the press times are less than 100ms apart. That should give reliable operation.

You can test if this is the problem simply by removing the debouncer2.fell() call. The code should then work reliably when only button 1 is pressed.

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