FanController.cpp

#include "FanController.h"

FanController::FanController(int pwm, int tach)
  : pwmPin(pwm), tachPin(tach), tachCounter(0), lastPulseTime(0), rpm(0), pwmValue(255) {}

void FanController::setup() {
  pinMode(pwmPin, OUTPUT);
  pinMode(tachPin, INPUT_PULLUP);
  analogWrite(pwmPin, pwmValue);
}

void FanController::setPWM(int value) {
  pwmValue = constrain(value, 0, 254);  // At 255, some fans stop sending valid TACH signals — temporary limit is 254
  analogWrite(pwmPin, pwmValue);
}

void FanController::pulseDetected() {
  unsigned long now = micros();
  if (now - lastPulseTime > 1000) { // debounce to ignore noise
    tachCounter++;
    lastPulseTime = now;
  }
}

void FanController::measureRPM() {
  noInterrupts();
  unsigned long count = tachCounter;
  tachCounter = 0;
  interrupts();

  if (count < 5) {
    rpm = 0;
  } else {
    rpm = (count * 60) / 2; // Assuming 2 pulses per revolution
  }
  
  updateSmoothedRPM(rpm);
}

void FanController::printStatus() {
  Serial.print("Fan RPM: ");
  Serial.println(rpm);
}

void FanController::updateSmoothedRPM(int newRPM) {
  rpmBuffer[bufferIndex] = newRPM;
  bufferIndex = (bufferIndex + 1) % SMOOTHING_WINDOW;

  int sum = 0;
  for (int i = 0; i < SMOOTHING_WINDOW; i++) {
    sum += rpmBuffer[i];
  }
  rpmSmoothed = sum / SMOOTHING_WINDOW;
}

int FanController::getSmoothedRPM() {
  return rpmSmoothed;
}