#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
// Define the pins for the ultrasonic sensor
#define echoPin 2
#define trigPin 3
#define led3 4
#define led4 5
#define led5 6

// Define variables for duration and distance
long duration;
int distance;

void setup() {
   Serial.begin(115200);
 pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
 pinMode(echoPin, INPUT); // Sets the echoPin as an Input
 if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
 Serial.println(F("SSD1306 allocation failed"));
 for(;;);
 }
 delay(500);
 display.clearDisplay();
 display.setTextSize(2);
 display.setTextColor(WHITE);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
  Serial.println("Distance measurement using Arduino Uno.");
  delay(500);
}

void loop() {
  // Send a trigger pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure the time taken for the echo
  duration = pulseIn(echoPin, HIGH);

  // Calculate distance in centimeters
  distance = duration * 0.0344 / 2;

  // Control LEDs based on distance thresholds
  if (distance > 20 && distance < 50) {
    digitalWrite(led3, HIGH);
  } else {
    digitalWrite(led3, LOW);
  }
  if (distance > 10 && distance <= 19 ) {
    digitalWrite(led4, HIGH);
  } else {
    digitalWrite(led4, LOW);
  }
  if (distance > 1 && distance <= 10) {
    digitalWrite(led5, HIGH);
  } else {
    digitalWrite(led5, LOW);
  }

  // Print distance to Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
   display.clearDisplay();
 display.setCursor(0, 25);
 // Display distance in cm
 display.print(distance);
 display.print("cm");
 // Display distance in inches
 /*display.print(distanceInch);
 display.print(" in");*/
 display.display();


  delay(500);
}