const byte encoderPin = A0;

void setup()
{
  Serial.begin(9600); // initialize serial communication
}

void loop() {
  static uint32_t lastZeroTime = 0;

  int rawValue = analogRead(encoderPin); // read analog input from encoder
  //float distance = interpolate(rawValue, calibValues, calibDist, 18); // interpolate distance from calibration data
  float distance = rawValue * 150.0 / 1024;

  float target = 5.47 / 60 / 1000 * (millis() - lastZeroTime);

  float error = target - distance;

  Serial.print("Displacement:");
  Serial.print(distance, 1); // output distance measurement to serial monitor with 0.1mm accuracy
  Serial.print("mm, Target:");
  Serial.print(target, 1); // output distance measurement to serial monitor with 0.1mm accuracy
  Serial.print("mm error:");
  Serial.print(error, 1); // output distance measurement to serial monitor with 0.1mm accuracy
  Serial.print("mm\n");

  delay(100);// wait for 100ms

  if (target > 150 ) {
    lastZeroTime = millis();
  }
}

float interpolate(float x, float xData[], float yData[], int dataSize) {
  // linear interpolation function
  for (int i = 0; i < dataSize - 1; i++) {
    if (x >= xData[i] && x <= xData[i + 1]) {
      return yData[i] + (yData[i + 1] - yData[i]) / (xData[i + 1] - xData[i]) * (x - xData[i]);
    }
  }
  return 0; // return 0 if x is outside of calibration range
}