#include <Wire.h>
#include <Adafruit_SSD1306.h>

#define TRIGGER_PIN 13
#define ECHO_PIN 12

Adafruit_SSD1306 display(21);

void setup() {
  Serial.begin(9600);
  Wire.begin(23, 22);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextColor(WHITE);
  display.setTextSize(2);
  display.setCursor(0,0);
  display.println("Distance:");
  display.display();
  pinMode(TRIGGER_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);

}

void loop() { 
  long duration, distance;
  
  digitalWrite(TRIGGER_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIGGER_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER_PIN, LOW);
  
  duration = pulseIn(ECHO_PIN, HIGH);
  
  distance = duration * 0.034 / 2;
  
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  display.clearDisplay();
  display.setCursor(0,0);
  display.print("Distance:");
  display.setCursor(0, 20);
  display.print(distance);
  display.print(" cm");
  display.display();
  delay(500);
}