Add Arduino fan controller functionality with PWM and tachometer support

ArduinoFanController.ino

@@ -0,0 +1,69 @@
+// Pin setup
+const int pwmPin = 9;      // PWM output to transistor base
+const int tachPin = 2;     // Tach input from fan
+const int buttonPin = 7;   // Pin of the button
+
+volatile unsigned long tachCount = 0;
+unsigned long lastTachCount = 0;
+unsigned long lastMillis = 0;
+int rpm = 0;
+int speed_percent = 0;
+int speed = 255 - (speed_percent * 2.55); // Valore di default
+
+// Interrupt routine for tachometer
+void tachISR() {
+  tachCount++;
+}
+
+void setup() {
+  pinMode(pwmPin, OUTPUT);
+  pinMode(tachPin, INPUT_PULLUP);
+  pinMode(buttonPin, INPUT_PULLUP);
+  attachInterrupt(digitalPinToInterrupt(tachPin), tachISR, FALLING);
+  Serial.begin(9600);
+}
+
+bool lastButtonState = HIGH;
+unsigned long lastDebounceTime = 0;
+const unsigned long debounceDelay = 200; // ms
+
+void loop() {
+  // // Imposta la velocità da seriale se disponibile
+  // if (Serial.available() > 0) {
+  //   speed_percent = Serial.parseInt();
+  //   if (speed_percent >= 0 && speed_percent <= 100) {
+  //     speed = map(speed_percent, 0, 100, 255, 0); // Converti percentuale in valore PWM (0-255)
+  //     Serial.print("Nuova velocità impostata: ");
+  //     Serial.print(speed_percent);
+  //     Serial.println("%");
+  //   }
+  // }
+
+  // Imposta la velocità se il pulsante è premuto
+  bool buttonState = digitalRead(buttonPin);
+  
+  if (buttonState == LOW && lastButtonState == HIGH && (millis() - lastDebounceTime) > debounceDelay) {
+    speed_percent = speed_percent + 10;
+    if (speed_percent > 105) {
+      speed_percent = 0;
+    }
+    speed = map(speed_percent, 0, 100, 255, 0);
+    lastDebounceTime = millis();
+  }
+  lastButtonState = buttonState;
+
+  analogWrite(pwmPin, speed);
+
+  // Calcola RPM ogni secondo
+  if (millis() - lastMillis >= 1000) {
+    // La ventola 4 pin di solito genera 2 impulsi per giro
+    rpm = (tachCount - lastTachCount) * 30; // 2 impulsi/giro, 60 sec/min
+    lastTachCount = tachCount;
+    lastMillis = millis();
+
+    Serial.print("Velocità impostata: ");
+    Serial.print(speed_percent);
+    Serial.print("% | RPM letti: ");
+    Serial.println(rpm);
+  }
+}