Code not Executing Reliably on Push Button Activation

Question

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);
 }
 }

Answer 1

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.