#include <LiquidCrystal_I2C.h>
Adafruit_LiquidCrystal lcd (0);

int trig_pin = 3;
int echo_pin = 2;
long echotime;
float Jarak;
const int Merah = 1;
const int Kuning = 2;
const int Hijau = 3;
const int SpeakerBuzzer = 4;

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, 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);
 }
    else if (Jarak > 200)
 {
digitalWrite (Hijau, LOW);
    }
  }