Issues Reading an encoder

Projects Programming
40

Anyone, any thoughts?

Why does the following code miss encoder pulses (as far as I can see, they are being missed only in one direction and fairly consistently):

/* 
This program is reading an encoder with an Arduino DUE, calculates the corresponding distance
 its cirumference travels and prints to serial interface. The code has a debounce which is added
 to deal with possible imperfections of the input signal. Only if the signal stays there longer
 than the set debounceDelay it is counted by the program.
 */
// Define the pins for the encoder
const int encoderPinA = 3;
const int encoderPinB = 4;

//Read the pines
#define readA digitalRead(encoderPinA)//faster than digitalRead()
#define readB digitalRead(encoderPinB)//faster than digitalRead()


// Variables for encoder state and distance
volatile bool lastStateA = LOW;
volatile bool lastStateB = LOW;
volatile long encoderCount = 0;
volatile long myCount = 0;
const int countsPerRevolution = 2000; // Counts per revolution of the encoder
const float encoderDiameter = 11.021;//11.07; // Diameter of the encoder in millimeters
float lastDistanceTraveled = 0; // Last distance traveled by the encoder's circumference
float totalDistanceTraveled = 0; // Total distance traveled by the encoder's circumference
const unsigned long debounceDelay = 10; // Adjust as needed (microseconds)

// Variables for printing to serial port conditions
unsigned long lastEncoderChangeTime = 0; // Time of the last encoder count change
unsigned long lastPrintTime = 200; // Time of the last print to serial monitor

// Setup function
void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Set encoder pins as inputs
  pinMode(encoderPinA, INPUT);
  pinMode(encoderPinB, INPUT);

  // Set output HIGH pins for using with external pull-up resistors
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  digitalWrite(8, HIGH);
  digitalWrite(9, HIGH);

  // Attach interrupts to the encoder pins
  attachInterrupt(digitalPinToInterrupt(encoderPinA), readEncoder1, CHANGE);
  attachInterrupt(digitalPinToInterrupt(encoderPinB), readEncoder2, CHANGE);
}

// Function to read the encoder
void readEncoder1() {
  // Update the encoder count based on the direction of rotation
  if (readB != readA) {
    encoderCount++;
  } else {
    encoderCount--;
  }
  // Update the time of the last encoder count change
  lastEncoderChangeTime = millis();
}

void readEncoder2() {
  // Update the encoder count based on the direction of rotation
  if (readA == readB) {
    encoderCount++;
  } else {
    encoderCount--;
  }
  // Update the time of the last encoder count change
  lastEncoderChangeTime = millis();
}


// Main loop
void loop() {
  //Reset the distance upon any input from the serial port
  if (Serial.available()){
    Serial.read();
    encoderCount = 0;
  }
  // Calculate distance traveled based on encoder counts and diameter
  float circumference = PI * encoderDiameter; // Calculate circumference
  float distance = ((encoderCount) * circumference) / (countsPerRevolution); // Calculate distance
  

  // Update total distance traveled
  totalDistanceTraveled = distance;

  // Check conditions for printing to serial port
  unsigned long currentTime = millis();
  if ((currentTime - lastEncoderChangeTime >= 500) && (totalDistanceTraveled != lastDistanceTraveled) && (currentTime - lastPrintTime >= 100)) {
    // Print distance traveled to serial monitor
    Serial.print(totalDistanceTraveled);
    Serial.print(", EncoderCount: ");
    Serial.println(encoderCount);
    // Update last printed distance and time values
    lastDistanceTraveled = totalDistanceTraveled;
    lastPrintTime = currentTime;
  }

}