81 lines
1.7 KiB
C++
81 lines
1.7 KiB
C++
#define FAN_WIRES 4
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#define PWM_PIN 3
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#define SENSOR_PIN 2
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#if FAN_WIRES == 4
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volatile unsigned int revs;
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#endif
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void setup()
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{
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Serial.begin(115200);
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Serial.println("FAN CONTROL");
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// prescaller for 31.372KHz
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// TCCR2B &= B11111000;
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// TCCR2B |= (0 << CS22) | (0 << CS21) | (1 << CS20);
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digitalWrite(PWM_PIN, LOW);
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pinMode(PWM_PIN, OUTPUT);
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#if FAN_WIRES == 4
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attachInterrupt(digitalPinToInterrupt(SENSOR_PIN), interruptHandler, FALLING);
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#endif
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}
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void loop()
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{
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int pwm, pwmGpio;
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for (pwm = 0 ; pwm <= 100 ; pwm += 10) {
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Serial.print(pwm);
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Serial.print("%: (");
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pwmGpio = pwm * 2.5;
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Serial.print(pwmGpio);
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Serial.print(") ");
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analogWrite(PWM_PIN, pwmGpio);
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delay(2000);
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#if FAN_WIRES == 4
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Serial.print(" speed = "); Serial.println(getSpeed());
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#else
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Serial.println();
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#endif
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}
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for (pwm = 90 ; pwm >= 0 ; pwm -= 10) {
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Serial.print(pwm);
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Serial.print("%: (");
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pwmGpio = pwm * 2.5;
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Serial.print(pwmGpio);
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Serial.print(") ");
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analogWrite(PWM_PIN, pwmGpio);
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delay(2000);
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#if FAN_WIRES == 4
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Serial.print(" speed = "); Serial.println(getSpeed());
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#else
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Serial.println();
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#endif
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}
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}
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#if FAN_WIRES == 4
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unsigned int getSpeed()
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{
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static unsigned long lastMillis;
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static unsigned int lastRead;
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unsigned long elapsed = millis() - lastMillis;
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if (elapsed > 1000) {
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detachInterrupt(digitalPinToInterrupt(SENSOR_PIN));
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double correctionFactor = 1000.0 / elapsed;
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lastRead = correctionFactor * revs / 2 * 60;
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revs = 0;
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lastMillis = millis();
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attachInterrupt(digitalPinToInterrupt(SENSOR_PIN), interruptHandler, FALLING);
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return lastRead;
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}
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}
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void interruptHandler(void)
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{
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revs++;
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}
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#endif
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