#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 11, 10, 9, 8, 7); /*the pins that the lcd will use*/

#define PIN_TRIGGER 3
#define PIN_INPUT 2


void setup() {
  Serial.begin(9600); /*setting the baud rate to be used (the rate at which the device outputs data)*/
  pinMode(PIN_TRIGGER, OUTPUT); /*setting the trigger pin to cause the HC-SR04 to ouput a signal*/
  pinMode(PIN_INPUT, INPUT); /*setting the input pin to display when the HC-SR04 detects a echo*/

  /*setting up the lcd*/
  lcd.setCursor(1,1); /*sets the start point for text to be outputted on the lcd*/
}

void loop() {
  /*taking a mesurement*/
  digitalWrite(PIN_TRIGGER, HIGH); /*writing a high voltage (5v) to the trigger pin, triggering an output*/
  delayMicroseconds(10);
  digitalWrite(PIN_TRIGGER, LOW); /*writing a low voltage (0v) to the trigger pin, to stop it outputting*/

  /*reading the result of the mesurement*/
  int duration_of_pulse = pulseIn(PIN_INPUT, HIGH);

  /*converting the duration to distance using convertions on the HC-SR04 data sheet*/
  int length_in_cm = duration_of_pulse / 58;
  Serial.println(length_in_cm);

  lcd.clear();
  lcd.print(length_in_cm);

  delay(1000);


}