DIY Ultrasonic Sensor Measurement

#include <Wire.h> //The "Wire" library should be pre installed with your IDE if not download it.
#include <LiquidCrystal_I2C.h> //This library requires you to manually download it so here is the download link: https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library

LiquidCrystal_I2C lcd(0x27, 16, 2);//I2C address and dimensions you may need to change it if your LCD is different.
int length = 0;//The length of the object
int range = 20;//Set the range of your obejct's length

//Declares the pins on the ultrasonic sensor
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);
}

void setup()
{
  // initialize the LCD
  lcd.begin();

  // Turn on the blacklight to print a message.
  lcd.backlight();
}

void loop()
{
  //Ok heres were all the math is. It may look a little scary but all it's doing is subtracting the distance the ultrasonic sensor senses by the range and getting the absoulute value of it which is the length of the object.
  length = abs((0.01723 * readUltrasonicDistance(9, 10) - range)); 
  //This just prints out "Object Length" and then the object length.
  lcd.print("Object Length:");
  lcd.setCursor(0,1);
 lcd.print(length);
 delay(500);
 lcd.clear();
}