/*
 * 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
 */

#define TRIG_PIN 18 // ESP32 pin GIOP23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 5 // ESP32 pin GIOP22 connected to Ultrasonic Sensor's ECHO pin
#define LED 2
#define LED2 4
float duration_us, distance_cm;

void setup() {
  // begin serial port
  Serial.begin (9600);

  // configure the trigger pin to output mode
  pinMode(TRIG_PIN, OUTPUT);
  // configure the echo pin to input mode
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED, OUTPUT);
  pinMode(LED2, OUTPUT);
}

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;
 
  // ligt up led if distance under limit
  if (distance_cm < 50) {digitalWrite(LED, HIGH);
  }else{digitalWrite(LED, LOW);
  }
 
  // print the value to Serial Monitor
  Serial.print("distanceA: ");
  Serial.print(distance_cm);
  Serial.println(" cm      ");
  Blink(LED2);
  delay(500);
}


void Blink(int x){
  digitalWrite(x, HIGH);
  delay(10);
  digitalWrite(x, LOW);
}