#include <Arduino.h>
#include <digitalWriteFast.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

const int TRIGGPIN = 4;
const int ECHOPIN = 5;

const int tanksensorHeight = 95;

const int tankheight = 80;

const int tankradius = 45;

constexpr double pi = 3.14159265358979323846;

int waterheight;

int distance;

long duration;

int lastDistance = -1;

const float SPEED_OF_SOUND = 0.034;

unsigned long previousMillis = 0;
const unsigned long interval = 1000;

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  lcd.clear();

  pinMode(TRIGGPIN, OUTPUT);
  pinMode(ECHOPIN, INPUT);
  Serial.println("HI Start");
}

void loop() {
  ULSensor();

  lcd.setCursor(0, 0);
  lcd.print("Distance:");
  lcd.setCursor(10, 0);
  lcd.print("     ");  // Clear old value
  lcd.setCursor(10, 0);
  lcd.print(distance);

  Serial.print("Distance:");
  Serial.println(distance);
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
  }
}

void ULSensor() {
  digitalWriteFast(TRIGGPIN, LOW);
  delayMicroseconds(2);
  digitalWriteFast(TRIGGPIN, HIGH);
  delayMicroseconds(10);
  digitalWriteFast(TRIGGPIN, LOW);
  duration = pulseIn(ECHOPIN, HIGH);
  distance = (duration * SPEED_OF_SOUND) / 2;
  //distance = round(distance * 100) / 100;
  distance = distance+1;
}