remocon_scanner.ino

void setup()
{
  Serial.begin(115200);
  Serial.println("----");
  pinMode(13, INPUT);
}


enum State {
  OFF = 0,
  ON,
  OUT
};

State current_state = OUT;
uint64 last_on = 0;
const uint64_t OFF_US = 50 * 1000;     /* 50ms */
const uint64_t TH_LEADER = 3000;      /* 3ms */
const uint64_t TH_ON     = 1350;      /* 0: 9ms, 1: 1.8ms */
const int pin = 13;
uint64_t previous_us = 0;

int pos = 0;
long intervals[1024] = {};

void loop() {
  uint64_t current_us;
  while((current_us = micros()) - previous_us < 100);
  previous_us = current_us;

  if (current_state == OUT) {
    if (digitalRead(pin) == HIGH) {
      current_state = ON;
      last_on = current_us;
    }
    return;
  }

  if (current_us - last_on > OFF_US) {
    current_state = OUT;
    /* Parse */
    for (int i = 1; i < pos; i+=8) {
      if (intervals[i] > TH_LEADER)
        break;
      byte b = 0;
      for (int j = 0; j < 8; j++) {
        if (intervals[i + j] > TH_ON)
          b |= (1 << j);
      }
      if (b < 0x10)
        Serial.print('0');
      Serial.print(b, HEX);
      Serial.print(" ");
    }
    Serial.println("");
    pos = 0;
    return;
  }

  if (current_state == ON) {
    /* ON */
    if (digitalRead(pin) == LOW)
      current_state = OFF;
  } else {
    /* OFF */
    if (digitalRead(pin) == HIGH) {
      if (current_us - last_on > 400) {
        intervals[pos++] = current_us - last_on;
        last_on = current_us;
      }
    }
  }
}