#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

int echoPin =11 ;
int trigPin =12;
float duration, distance_cm;
int currentTime, startTime;


// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(115200);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);
  display.clearDisplay();

  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 10);
  // Display static text
  display.println("Distance in cm:");
  display.display(); 
}

void loop() {
  
  float distance= getDistance();
  Serial.println(distance);
  currentTime= millis();
  if ((currentTime - startTime) > 1000) {
    startTime = currentTime;
    display.setCursor(50, 20);
    display.println(distance);
    display.display();
    display.clearDisplay();
      }
}

float getDistance(){
  digitalWrite(trigPin, LOW);
  delayMicroseconds(5);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance_cm = (duration/2.0)*0.0343 ;
  //distance_inch = (duration/2.0)*0.0135 ;
  return distance_cm;
}