#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);

int trig_pin = 9;
int echo_pin = 8;
long echotime;
float Jarak;
const int Merah = 1;
const int Kuning = 2;
const int Hijau = 3;
const int SpeakerBuzzer = 0;

void setup()
{
lcd.begin (16, 2); 
  pinMode (trig_pin, OUTPUT); 
  pinMode (echo_pin, INPUT); 
  digitalWrite (trig_pin, LOW); 
  pinMode (Merah, OUTPUT); 
  pinMode (Kuning, OUTPUT); 
  pinMode (Hijau, OUTPUT); 
  pinMode (SpeakerBuzzer, OUTPUT);
  
}
void loop()
{
  
lcd.setCursor(0, 0); 
  lcd.print("Sensor Jarak :"); 
  digitalWrite (trig_pin, HIGH); 
  delayMicroseconds (10);
digitalWrite (trig_pin, HIGH); 
  delayMicroseconds (10);
digitalWrite (trig_pin, LOW);
echotime= pulseIn (echo_pin, HIGH);
Jarak= 0.0001*((float)echotime*340.0)/2.0;
lcd.setCursor(0,1); 
lcd.print (Jarak);
lcd.print("cm");
delay(500);
  
if (Jarak > 100 && Jarak < 200)
{
digitalWrite (Hijau, HIGH);
}
    
 else if (Jarak > 50 && Jarak < 100)
 {
digitalWrite (Kuning, HIGH);
digitalWrite (Hijau, LOW);
digitalWrite (SpeakerBuzzer, HIGH); delay(500);
digitalWrite (Kuning, LOW); digitalWrite (Hijau, LOW);
digitalWrite (SpeakerBuzzer, LOW); delay(500);
}

else if (Jarak < 50)
{
digitalWrite (Merah, HIGH);
digitalWrite (Hijau, LOW);
digitalWrite (SpeakerBuzzer, HIGH);
delay (200); digitalWrite (Merah, LOW);
digitalWrite (Hijau, LOW);
digitalWrite (SpeakerBuzzer, LOW);
delay (100);
}
}