#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#define TRIGGER_PIN  7  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN     6  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters). Maximum sensor distance is rated at 400-500cm.

// Define LCD parameters
#define LCD_ADDRESS 0x27 // I2C address of your LCD module
#define LCD_COLS 16      // Number of columns your LCD has

// Initialize Ultrasonic sensor
long duration;
int distance;

void setup() {
  Wire.begin();
  Serial.begin(9600);
}

void loop() {
  // Read distance from Ultrasonic sensor
  distance = getDistance();
  
  // Display the distance as a bargraph on LCD
  displayBarGraph(distance);
  
  delay(500); // Wait for a short duration before taking another measurement
}

int getDistance() {
  // Send pulse to trigger ultrasonic sensor
  pinMode(TRIGGER_PIN, OUTPUT);
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);
  
  // Read pulse from echo pin
  pinMode(ECHO_PIN, INPUT);
  duration = pulseIn(ECHO_PIN, HIGH);
  
  // Calculate distance based on the duration of the pulse
  int distance = duration * 0.034 / 2; // Divide by 2 because the pulse traveled to the object and back
  
  return distance;
}

void displayBarGraph(int distance) {
  Wire.beginTransmission(LCD_ADDRESS);
  Wire.write(0x80); // Set cursor to the first column of the first row
  
  // Calculate the number of bars to display based on distance
  int numBars = map(distance, 0, MAX_DISTANCE, 0, LCD_COLS);
  
  // Display the progression bar
  for (int i = 0; i < LCD_COLS; i++) {
    if (i < numBars) {
      Wire.write('#'); // Display a filled bar
    } else {
      Wire.write(' '); // Display a space
    }
  }
  
  Wire.endTransmission();
}