讀 4pin 風扇 RPM

 

uint8_t GPIO_Pin = D2;

uint8_t PWM_Pin = D6;

unsigned long duration;

uint8_t getData;

unsigned int rpm;

unsigned long timeold;

void setup() {

  Serial.begin(115200);

  attachInterrupt(digitalPinToInterrupt(GPIO_Pin), IntCallback, RISING);

  pinMode(GPIO_Pin, INPUT_PULLUP);

  pinMode(PWM_Pin, OUTPUT);

  analogWrite(PWM_Pin, 0);

  duration = 0;

  rpm = 0;

  timeold = 0;

}

void loop() {

  if (Serial.available()) {      // If anything comes in Serial (USB),

    getData = Serial.read();   // read it and send it out Serial1 (pins 0 & 1)

    if( getData >='0' && getData <=':' ){

      //Serial.println(getData);

      analogWrite(PWM_Pin, map((getData-'0')*10, 0, 100, 0, 255) );

      Serial.print("analogWrite ");

      Serial.println((getData-'0')*10);

    }

  }

  

  if (duration >= 2) {

    rpm = 30 *1000 / (millis() - timeold) * duration;

    //Serial.println(duration,DEC);

    //Serial.println((millis() - timeold),DEC);

    Serial.print("目前轉速:");

    Serial.println(rpm,DEC);

    timeold = millis();

    duration = 0;

  }

}

ICACHE_RAM_ATTR void IntCallback(){

  duration++;

}