rotarydial.ino

/* Rotary Dial encoder
encode the rotary dial of an old analog phone.
by Christoph Gerneth
*/
const int active_pin = 2;
const int pulse_pin = 3;

int number_counter = 0;
int last_pulse_state = 0; // last state of the rotary dial pulser
int last_active_state = 0;

// the following variables are unsigned long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50;    // the debounce time; increase if the output flickers


void setup(){
  pinMode(active_pin, INPUT);  // configure rotary pins
  pinMode(pulse_pin, INPUT);
  digitalWrite(pulse_pin, HIGH);  // pull all keys high
  digitalWrite(active_pin, HIGH);
  Serial.begin(9600);
  Serial.println("intializing..");
}

void loop() {
  // read inputs
  int active_state = digitalRead(active_pin);
  int pulse_state = digitalRead(pulse_pin);
  
  if (pulse_state != last_pulse_state){
    if ((millis() - lastDebounceTime) > debounceDelay) {
    // actual button pressed
      number_counter++;
      lastDebounceTime = millis();
    }
  }
  
  if (active_state == 0 && number_counter > 0){
    Serial.print("counted ");  
    Serial.println(number_counter-1);
    number_counter = 0;
  }
  
  last_active_state = active_state;
  last_pulse_state = pulse_state;
}