/*
  1602 LCD Display with I2C and HC-SRO4 Demo
  Created by Neo December 2019
  https://www.unix.com
*/
#include <LiquidCrystal_I2C.h>
const int i2c_addr = 0x27;    // bus address from LCD display
LiquidCrystal_I2C lcd(i2c_addr, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);
const int trigPin = 9;    //  HC-SRO4 trig
const int echoPin = 10;   //  HC-SRO4 echo
const int maxRange = 400; //  HC-SRO4 max range in cm
const int minRange = 2;   //  HC-SRO4 min range in cm
long duration;
float distanceCm, distanceInch;
void setup()
{
    lcd.begin(16, 2); // Initializes LCD screen and specifies chars (16) and rows (2)
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
}
void loop()
{
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);
    duration = pulseIn(echoPin, HIGH);
    distanceCm = duration * 0.034 / 2;
    distanceInch = duration * 0.0133 / 2;
    // Set range of HC-SRO4
    if (distanceCm > maxRange || distanceCm < minRange)
    {
        distanceCm = 0;
        distanceInch = 0;
    }
    //first row
    lcd.setCursor(0, 0); // Sets the cursor location
    lcd.print("Dist(cm): ");
    if (distanceCm > 0)
    {
        lcd.print(distanceCm, 1);
        lcd.print("     ");
    }
    else
    {
        lcd.print("         "); // easy clear :)
    }
    // second row
    lcd.setCursor(0, 1);
    lcd.print("Dist(in): ");
    if (distanceCm > 0)
    {
        lcd.print(distanceInch, 1);
        lcd.print("    ");
    }
    else
    {
        lcd.print("         "); // easy clear :)
    }

    delay(200);
}