/*
    int trigPin = 13; 
    int echoPin = 12;
    int duration, distance;

    void LedON(int dist){
    
      digitalWrite(10, dist <= 25);
      digitalWrite(8, dist <= 20);
      digitalWrite(7, dist <= 15);
      digitalWrite(5, dist <= 10);
      
    }

    void setup() { 
      Serial.begin (9600); 
      pinMode(trigPin, OUTPUT); 
      pinMode(echoPin, INPUT); 

      pinMode(10, OUTPUT);
      pinMode(8, OUTPUT);
      pinMode(7, OUTPUT);
      pinMode(5, OUTPUT);
    } 
     
    void loop() {
      digitalWrite(trigPin, LOW); 
      delayMicroseconds(2); 

      digitalWrite(trigPin, HIGH);
      delayMicroseconds(10); 
      
      digitalWrite(trigPin, LOW); 
      
      duration = pulseIn(echoPin, HIGH); 
      distance = duration / 58;
      Serial.print(distance); 
      Serial.println(" cm"); 
      LedON(distance);
      delay(100);
    }
*/
/*
 * This ESP32 code is created by esp32io.com
 *
 * This ESP32 code is released in the public domain
 *
 * For more detail (instruction and wiring diagram), visit https://esp32io.com/tutorials/esp32-ultrasonic-sensor-piezo-buzzer
 */

#define TRIG_PIN   26 // ESP32 pin GPIO26 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN   25 // ESP32 pin GPIO25 connected to Ultrasonic Sensor's ECHO pin
#define LED_PIN 17 // ESP32 pin GPIO17 connected to Piezo Buzzer's pin
#define BUZZER_PIN 16 // ESP32 pin GPIO16 connected to Led's pin
//#define DISTANCE_THRESHOLD 150 // centimeters

// variables will change:
float duration_us, distance_cm;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);   // set ESP32 pin to output mode
  pinMode(ECHO_PIN, INPUT);    // set ESP32 pin to input mode
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  Serial.begin(115200);
}

void loop() {
  // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration_us = pulseIn(ECHO_PIN, HIGH);
  // calculate the distance
  distance_cm = 0.017 * duration_us;
  
  Serial.print("Measured distance: ");
  Serial.println(distance_cm);
 
    if (distance_cm < 350 & distance_cm > 200) {
      tone(BUZZER_PIN, 400, 250); // Plays 262Hz tone for 0.250 seconds
      delay (1000);
      tone(BUZZER_PIN, 800, 250); // Plays 262Hz tone for 0.250 seconds
    }

    if (distance_cm < 200 & distance_cm > 100) {
      tone(BUZZER_PIN, 1000, 250); // Plays 262Hz tone for 0.250 seconds
      delay (100);
      tone(BUZZER_PIN, 1200, 250); // Plays 262Hz tone for 0.250 seconds
    }

    if (distance_cm < 100) {
      digitalWrite(LED_PIN, HIGH);
      tone(BUZZER_PIN, 1400, 250); // Plays 262Hz tone for 0.250 seconds
      delay (100);
      tone(BUZZER_PIN, 1600, 250); // Plays 262Hz tone for 0.250 seconds
    }
  else  digitalWrite(LED_PIN, LOW);

}