Sim808 speedometer to display

#https://www.youtube.com/watch?v=JVchiLYcH48
# SIM808 arduino code from this video

#using libs from https://github.com/DFRobot/DFRobot_SIM808 for sim808 and https://github.com/adafruit/Adafruit_SSD1306 for display


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




#include <DFRobot_sim808.h>
#include <SoftwareSerial.h>

//#define PIN_TX    10
//#define PIN_RX    11
//SoftwareSerial mySerial(PIN_TX,PIN_RX);
//DFRobot_SIM808 sim808(&mySerial);//Connect RX,TX,PWR,

DFRobot_SIM808 sim808(&Serial);

// OLED display TWI address
#define OLED_ADDR   0x3C

Adafruit_SSD1306 display(-1);

#if (SSD1306_LCDHEIGHT != 32)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif



//DFRobot_SIM808 sim808(&Serial);

void setup() {
  //mySerial.begin(9600);
  Serial.begin(9600);



  // initialize and clear display
  display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR);
  display.clearDisplay();
  display.display();

  // display a line of text
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(10,10);
  display.print("Ieskomas GPS...");

  // update display with all of the above graphics
  display.display();




  //******** Initialize sim808 module *************
  while(!sim808.init()) {
      delay(1000);
      Serial.print("Sim808 init error\r\n");
  }

  //************* Turn on the GPS power************
  if( sim808.attachGPS())
      Serial.println("Open the GPS power success");
  else
      Serial.println("Open the GPS power failure");

}

void loop() {
   //************** Get GPS data *******************
   if (sim808.getGPS()) {

    /*
    Serial.print(sim808.GPSdata.year);
    Serial.print("/");
    Serial.print(sim808.GPSdata.month);
    Serial.print("/");
    Serial.print(sim808.GPSdata.day);
    Serial.print(" ");
    Serial.print(sim808.GPSdata.hour);
    Serial.print(":");
    Serial.print(sim808.GPSdata.minute);
    Serial.print(":");
    Serial.print(sim808.GPSdata.second);
    Serial.print(":");
    Serial.println(sim808.GPSdata.centisecond);

    Serial.print("latitude :");
    Serial.println(sim808.GPSdata.lat,6);

    sim808.latitudeConverToDMS();
    Serial.print("latitude :");
    Serial.print(sim808.latDMS.degrees);
    Serial.print("\^");
    Serial.print(sim808.latDMS.minutes);
    Serial.print("\'");
    Serial.print(sim808.latDMS.seconeds,6);
    Serial.println("\"");
    Serial.print("longitude :");
    Serial.println(sim808.GPSdata.lon,6);
    sim808.LongitudeConverToDMS();
    Serial.print("longitude :");
    Serial.print(sim808.longDMS.degrees);
    Serial.print("\^");
    Serial.print(sim808.longDMS.minutes);
    Serial.print("\'");
    Serial.print(sim808.longDMS.seconeds,6);
    Serial.println("\"");

    Serial.print("speed_kph :");
    Serial.println(sim808.GPSdata.speed_kph);
    Serial.print("heading :");
    Serial.println(sim808.GPSdata.heading);

    //************* Turn off the GPS power ************
   // sim808.detachGPS();
   */


    display.clearDisplay();
    display.setTextSize(2);
    display.setCursor(0,10);
    display.print(sim808.GPSdata.speed_kph);
    display.print(" km/h");
    display.display();

  }

}