const int trigPin = 9;
const int echoPin = 10;
const int ProxSensor = 2;
const int relayPin = 12;
const int buzzerPin = 3;
int inputVal = 0;
long duration;
int distance;
boolean IROK = false;
boolean UltraOK = false;
char pi = 'N';

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(relayPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ProxSensor, INPUT);
  digitalWrite(buzzerPin, LOW);
  digitalWrite(relayPin, LOW);
  Serial.begin(9600);

}

void loop() {

  IROK = false;
  UltraOK = false;
  pi = 'N';

  distance = readDistance();
  if (distance < 70) UltraOK = true;
  else UltraOK = false;
  if (digitalRead(ProxSensor) == LOW ) IROK = true;
  else  IROK = false;

  
  if (Serial.available() > 0) {
    pi = Serial.read();
  }

  delay(500);

  Serial.println(pi);
  Serial.println(IROK);
  Serial.println(UltraOK);

  if (IROK && UltraOK && pi == 'o') {
    openShifter();
  }
  IROK = false;
  UltraOK = false;
}

void openShifter() {
  digitalWrite(relayPin, HIGH);
  playBuzzer(300, true);
  delay(7000);
  digitalWrite(relayPin, LOW);
  IROK = false;
  UltraOK = false;
  pi = 'N';
  serialFlush();
}

void serialFlush() {
  while (Serial.available() > 0) {
    char t = Serial.read();
  }
}

void playBuzzer(int time, boolean ok) {
  tone(buzzerPin, 3000);
  delay(time / 2);
  noTone(buzzerPin);
  delay(100);
  tone(buzzerPin, 3000);
  delay(time / 2);
  noTone(buzzerPin);

}

int readDistance() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  return duration * 0.034 / 2;

}