#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 
#define SCREEN_HEIGHT 64 
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
const int trigPin = 5; 
const int echoPin = 18; 
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701
long duration;
int distanceCm;
int distanceInch;
void setup() {
 Serial.begin(115200);
 pinMode(trigPin, OUTPUT);
 pinMode(echoPin, INPUT); 
 if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
 Serial.println(F("SSD1306 allocation failed"));
 for(;;);
 } 
 delay(500);
 display.clearDisplay();
 display.setTextSize(2);
 display.setTextColor(WHITE);
} 
void loop() {
 // Clears the trigPin
 digitalWrite(trigPin, LOW);
 delayMicroseconds(2);
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(10);
 digitalWrite(trigPin, LOW);

 duration = pulseIn(echoPin, HIGH);
 distanceCm = duration * SOUND_SPEED/2; 
 
 distanceInch = distanceCm * CM_TO_INCH;
 Serial.print("Distance (cm): ");
 Serial.println(distanceCm);
 Serial.print("Distance (inch): ");
 Serial.println(distanceInch);
 display.clearDisplay();
 display.setCursor(0, 25);
 //Display distance in cm
 display.print(distanceCm);
 display.print(" cm");

 display.display(); 
 delay(500); 
}