/*  Project : Ultrasonic reverse parking sersor with distance display and buzzer beep
    Arduino : UNO
    Group members : Muhammad Danish Shakir Bin Mohd Fadzilah
                    Mohd Naqiuddin Bin Rostapar
                    Wan Ahmad Firdaus Bin Wan Hasbullah
*/

#include <LiquidCrystal_I2C.h>

#define ECHO_PIN 5
#define TRIG_PIN 4

int switchPin = 7;
int switchState = 0;   

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(1, 0);
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(switchPin, INPUT);
}

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();

  lcd.setCursor(2,2);
  lcd.print(F("Distance : "));
  lcd.print(distance);
  

  if (distance >= 100){
    lcd.setCursor(7,0);
    lcd.print("((R))");
    lcd.setCursor(3,1);
    lcd.print("Please reverse");
    tone(8, 296, 600);
    delay(800);
    noTone(8);
  }
  
  if (distance >75 && distance<100){
    lcd.setCursor(7,0);
    lcd.print("((R))");
    lcd.setCursor(3,1);
    lcd.print(" Almost there ");
    tone(8, 296, 100);
    delay(300);
    noTone(8);
   }

  if (distance <= 75) {
    lcd.setCursor(7,0);
    lcd.print("((P))");
    lcd.setCursor(2,1);
    lcd.print("     STOP!     ");
    tone(8, 296);
  }
}