ultrasonic_lcd

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // set the LCD address to 0x27 for a 16 chars and 2 line display


// Define Trig and Echo pin:
#define trigPin 3
#define echoPin 4
long max_distance = 5000;

// Define variables:
float duration;
float distance;

void setup() {
  // Define inputs and outputs
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
  lcd.init();
  lcd.backlight();


  // Begin Serial communication at a baudrate of 9600:

}

void loop() {
  // Clear the trigPin by setting it LOW:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
 // Trigger the sensor by setting the trigPin high for 10 microseconds:
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin. pulseIn() returns the duration (length of the pulse) in microseconds:
  duration = pulseIn(echoPin, HIGH);

  // Calculate the distance:
  distance = duration*0.034/2; // cm
  distance = distance*10; // convert to mm

  // Print the distance on the Serial Monitor (Ctrl+Shift+M):
  Serial.print("Distance = ");
  Serial.print(distance);
  //distance = max_distance - distance;
  Serial.println(" mm");
  String str_jarak = String(distance,0) + "mm";

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distance");
  lcd.setCursor(0, 1);
  lcd.print(str_jarak);
  delay(1000);
}