/*
  HC-SR04 Ultrasonic Sensor Example.

  Turn the LED on when an object is within 100cm range.


*/

#define ECHO_PIN 2
#define TRIG_PIN 3
#define LED_PIN 13
#define BUZZER 5
const int Mesure_Max = 100 ;        //   en cm
const int Mesure_Min = 20 ;         //   en cm
long Duree;
float Distance;                     // distance mesurée


void setup() {
  Serial.begin(115200);
  pinMode(BUZZER, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);

  digitalWrite(LED_PIN, LOW);
  noTone(BUZZER);
}


// +++++++++++ Routine mesure par Ultra son +++++++++++++++++
float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}
// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


void loop() {
  Distance = readDistanceCM();

  if (Distance >= Mesure_Max || Distance <= Mesure_Min) {
    Serial.println("Hors plage");
    noTone(BUZZER);
  }

  else {
    Serial.print("Distance Mesurée: ");
    Serial.println(Distance);
    tone(BUZZER, Distance * 40);           //fréquence
  }

  //bool isNearby = Distance < 100;     // test seuil
  //  digitalWrite(LED_PIN, isNearby);
  // tone(BUZZER, 1000, 1000);             //fréquence , durée

  delay(100);
}