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

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

#define OLED_MOSI   13
#define OLED_CLK   14
#define OLED_DC    4
#define OLED_CS    15
#define OLED_RESET 0
Adafruit_SSD1306 oled(SCREEN_WIDTH, SCREEN_HEIGHT,OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

const int trigPin = D0;
const int echoPin = D1;

//define sound speed in cm/uS
#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); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input

if(!oled.begin(SSD1306_SWITCHCAPVCC))
{
  Serial.println(F("SSD1306 allocation failed"));
  for(;;);
}
delay(500);
oled.clearDisplay();

oled.setTextSize(2);
oled.setTextColor(WHITE);
}

void loop(){
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  
  // Calculate the distance
  distanceCm = duration * SOUND_SPEED/2;
  
  // Convert to inches
  distanceInch = distanceCm * CM_TO_INCH;
  
  // Prints the distance in the Serial Monitor
  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  Serial.print("Distance (inch): ");
  Serial.println(distanceInch);

  oled.clearDisplay();
  oled.setCursor(0, 25);
  // Display distance in cm
  oled.print(distanceCm);
  oled.print(" cm");
  
  // Display distance in inches
  /*oled.print(distanceInch);
  oled.print(" in");*/
  oled.display(); 

  delay(500);  
}

//@ApePanthiya ICT