#include <LiquidCrystal_I2C.h>

const int trigPin = 5;
const int echoPin = 18;

//define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;
LiquidCrystal lcd(0x27,40,2);

void ledAman()
{
  digitalWrite(2, HIGH);
  digitalWrite(19, LOW);
  digitalWrite(4, LOW);
}
void ledSiaga(int siaga)
{
  if(siaga == 1 || siaga==2)
  {
    digitalWrite(2, LOW);
    digitalWrite(19, LOW);
    digitalWrite(4, HIGH);
  }
  else
  {
    digitalWrite(2, LOW);
    digitalWrite(19, HIGH);
    digitalWrite(4, LOW);
  }
    
  
}
void setup() {
  Serial.begin(115200); // Starts the serial communication
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  pinMode(2, OUTPUT); // LED Hijau
  pinMode(4, OUTPUT); // LED Kuning
  pinMode(19, OUTPUT); // LED Merah
}

void loop() {
  // 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);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  
  // Convert to inches
  //distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Jarak (cm): ");
  Serial.println(distanceCm);
  if (distanceCm < 120)
  {
    ledSiaga(3);
    Serial.println("Kondisi Siaga 3");
  }
  else if (distanceCm >= 120 && distanceCm <150)
  {
    ledSiaga(2);
    Serial.println("Kondisi Siaga 2");
  }
  else if (distanceCm >= 150 && distanceCm < 180)
  {
    ledSiaga(1);
    Serial.println("Kondisi Siaga 1");
  }
  else
  {
    ledAman();
    Serial.println("Kondisi Aman");
  }
    

  delay(1000);
}