#define ECHO_PIN 2
#define TRIG_PIN 3
#include <LiquidCrystal_I2C.h>
float cm;
float inches;
LiquidCrystal_I2C lcd(0x27,20,4);

void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  lcd.init();	// initialize the lcd
  // Print a message to the LCD.
  lcd.backlight();
  lcd.print("--> Distance <--");
	delay(3000);
	lcd.clear();
}
long readUltrasonicDistance(int triggerPin, int echoPin)
{
	pinMode(triggerPin, OUTPUT);  // Clear the trigger
	digitalWrite(triggerPin, LOW);
	delayMicroseconds(2);
	// Sets the trigger pin to HIGH state for 10 microseconds
	digitalWrite(triggerPin, HIGH);
	delayMicroseconds(10);
	digitalWrite(triggerPin, LOW);
	pinMode(echoPin, INPUT);
	// Reads the echo pin, and returns
	// the sound wave travel time in microseconds
	return pulseIn(echoPin, HIGH);
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  float distance = readDistanceCM();

  bool isNearby = distance < 100;
  digitalWrite(LED_BUILTIN, isNearby);

  Serial.print("Measured distance: ");
  Serial.println(readDistanceCM());

  delay(100);
    cm = 0.0344/2 * readUltrasonicDistance(3, 2);
	inches = (cm / 2.54);
 
	lcd.setCursor(0,0);
	lcd.print("Inches");
	lcd.setCursor(4,0);
	lcd.setCursor(12,0);
	lcd.print("cm");
	lcd.setCursor(1,1);
	lcd.print(inches, 1);
	lcd.setCursor(11,1);
	lcd.print(cm, 1);
	lcd.setCursor(14,1);
	delay(2000);
	lcd.clear();
}