About:

In this project we will learn how to interface GPS module with esp8266 as main controller to show GPS data on OLED display. We will read and display various elements from GPS like Speed, Clock, Date, Location, Altitude, Trip distance, Number of connected satellites, Cardinals (moving direction), etc. We can use this project in cars or other moving vehicles.

In next update I am planning to build a web-server using esp8266 to receive data from GPS in smart phones and generate geographical location on online 2D maps using longitude and latitude.

Components:

• ESP8266 NodeMCU board
• Ublox neo-6m GPS module
• OLED i2c display 128x64px
• Momentary push buttons – 2Nos
• Software : Arduino IDE

Circuit Diagram:

Code:

/*
 * Project: Mini GPS Display using Ublox neo-6m and ESP8266
 * Author: Pranay SS, eTechPath
 * Website: www.etechpath.com
 * Tutorial Link: 
   
Mini GPS Display using Ublox neo-6m module and ESP8266 nodemcu

 * Video Link: https://youtu.be/ExPBmiz1cj0
 * 
 */
 
 
 
 #include <Arduino.h>
#include <U8g2lib.h>
#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif
#define menu D3
#define enter D4
int key = 0;
double Home_LAT = 0;
double Home_LNG = 0;


//sat20x20px logo
U8G2_SSD1306_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=*/ U8X8_PIN_NONE);
static const unsigned char u8g_logo_sat[] U8X8_PROGMEM = {
  0x00, 0x01, 0x00, 0x80, 0x07, 0x00, 0xc0, 0x06, 0x00, 0x60, 0x30, 0x00,
  0x60, 0x78, 0x00, 0xc0, 0xfc, 0x00, 0x00, 0xfe, 0x01, 0x00, 0xff, 0x01,
  0x80, 0xff, 0x00, 0xc0, 0x7f, 0x06, 0xc0, 0x3f, 0x06, 0x80, 0x1f, 0x0c,
  0x80, 0x4f, 0x06, 0x19, 0xc6, 0x03, 0x1b, 0x80, 0x01, 0x73, 0x00, 0x00,
  0x66, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x3c, 0x00, 0x00, 0x70, 0x00, 0x00
};
//wave10px logo
static const unsigned char u8g2_logo_wave[] U8X8_PROGMEM ={
  0xE0, 0x03, 0x18, 0x00, 0xC4, 0x01, 0x32, 0x00, 0x8A, 0x01, 0x69, 0x00, 
  0x25, 0x00, 0x95, 0x01, 0x95, 0x01, 0x01, 0x00, };
//sat40x35px logo



// The serial connection to the GPS device
#include <SoftwareSerial.h>
static const int RXPin = D5, TXPin = D6;
static const uint32_t GPSBaud = 9600;
SoftwareSerial ss(RXPin, TXPin);

//GPS Library
#include <TinyGPS++.h>
TinyGPSPlus gps;

//Program variables
double Lat;
double Long;
double Alt;
int day, month, year;
//int hour, minute, second;

int num_sat, gps_speed;
String heading;


//SETUP
void setup() {
  pinMode(menu, INPUT_PULLUP);
  pinMode(enter, INPUT_PULLUP);

  ss.begin(GPSBaud);
   u8g2.begin();

//PrintingLoadingPage
    u8g2.firstPage();
  do {
    print_page1();
  } while ( u8g2.nextPage() );
  delay(5000);



  
}//END SETUP


//LOOP
void loop() {

  Get_GPS(); //Get GPS data

  if (digitalRead(menu) == LOW)
     key = (key+1);
             //else if (digitalRead(menu) == LOW)
             //key = (key-1);
  if (key<0 or key>3)
     key = 0;


   switch (key)

{ 
  case 0:
      u8g2.firstPage();
  do {
     print_Clock();
  } while ( u8g2.nextPage() );
  delay(10);
  break;
  case 1:
   u8g2.firstPage();
  do {
   print_speed();
  } while ( u8g2.nextPage() );
  delay(10);
  break;
  case 2:
  u8g2.firstPage();
  do {
    print_location();
  } while ( u8g2.nextPage() );
  delay(10);

  break;
 case 3:
     u8g2.firstPage();
  do {
    print_Trip();
    if (digitalRead(enter) == LOW)
    { Home_LAT = gps.location.lat();
    Home_LNG = gps.location.lng(); }
    else 
    { u8g2.setFont(u8g2_font_courR08_tr);
      u8g2.setCursor(0, 64);
      u8g2.print("Press Enter to reset");
    }   
   
  } while ( u8g2.nextPage() );
  delay(10);

  break;

 }

   
} //end of loop


void print_page1() {
  u8g2.drawXBMP(0, 0, 20, 20, u8g_logo_sat);
  u8g2.setFont( u8g2_font_crox1cb_tf);
  //u8g2.setFont(u8g2_font_helvB12_tf);
  //u8g2.setFont(u8g2_font_timB12_tf);
  u8g2.setCursor(45, 20);
  u8g2.print("MINI GPS");
  //u8g2.setFont(u8g2_font_7x13B_tf);
  u8g2.setFont(u8g2_font_nine_by_five_nbp_tf);
  u8g2.setCursor(55, 35);
  u8g2.print("by  eTechPath");
  u8g2.setFont(u8g2_font_nine_by_five_nbp_tf);
  u8g2.setCursor(0, 60);
  u8g2.print("Loading");
  u8g2.setFont(u8g2_font_glasstown_nbp_tf);
  u8g2.setCursor(40, 60);
  u8g2.print(" . . . . . ");  
   
}  


void print_Clock()
  {
    u8g2.setFont(u8g2_font_courB08_tn);
    u8g2.setCursor(105, 64);
    u8g2.print( num_sat, 5);
    u8g2.drawXBMP(118, 54, 10, 10, u8g2_logo_wave);
    
    
    u8g2.setFont(u8g2_font_crox1cb_tf);
    u8g2.setCursor(20, 10);
    u8g2.print("GPS CLOCK");
    u8g2.drawLine(0,12,128,12);
    u8g2.setFont(u8g2_font_t0_22b_tn);
    u8g2.setCursor(20, 42);
    printTime(gps.time);
    // u8g.print(gps.date);
    //Get_Date();
    u8g2.setFont(u8g2_font_nine_by_five_nbp_tf);
    u8g2.setCursor(0, 64);
    printDate(gps.date);
  
  }
  
void print_speed() {

  
 u8g2.setFont(u8g2_font_crox1cb_tf);
    u8g2.setCursor(16, 10);
    u8g2.print("Speedometer");
    u8g2.drawLine(0,15,128,15);
    
  u8g2.setFont(u8g2_font_t0_22b_tn);
  u8g2.setCursor(5, 42);
  u8g2.print(gps_speed , DEC);
  u8g2.setFont(u8g2_font_glasstown_nbp_tf);
  u8g2.setCursor(62, 42);
  u8g2.print("km/h");


  u8g2.setFont(u8g2_font_courB08_tn);
  u8g2.setCursor(105, 64);
  u8g2.print( num_sat, 5);
  u8g2.drawXBMP(118, 54, 10, 10, u8g2_logo_wave);

  u8g2.setFont(u8g2_font_glasstown_nbp_tf);
  u8g2.setCursor(0,64);
  u8g2.print("Direction:");
  u8g2.setCursor(45,64);
  u8g2.print( heading);
}

void print_location()
{
  u8g2.setFont(u8g2_font_crox1cb_tf);
  u8g2.setCursor(10, 10);
  u8g2.print("GPS Location");
  u8g2.drawLine(0,12,128,12);

  u8g2.setFont(u8g2_font_nine_by_five_nbp_tf);
  u8g2.setCursor(5, 28);
  u8g2.print("Long: ");
  u8g2.setCursor(40, 28);
  u8g2.print( Long, 6);

  u8g2.setCursor(5, 43);
  u8g2.print("Lat: ");
  u8g2.setCursor(40, 43);
  u8g2.print( Lat, 6);

  u8g2.setCursor(0, 64);
  u8g2.print("Alt: ");
  u8g2.setCursor(20, 64);
  u8g2.print( Alt, 3);

  u8g2.setFont(u8g2_font_courB08_tn);
  u8g2.setCursor(105, 64);
  u8g2.print( num_sat, 5);
  u8g2.drawXBMP(118, 54, 10, 10, u8g2_logo_wave);
  
  }

// This custom version of delay() ensures that the gps object
// is being "fed".
static void smartDelay(unsigned long ms)
{
  unsigned long start = millis();
  do
  {
    while (ss.available())
      gps.encode(ss.read());
  } while (millis() - start < ms);
}


void Get_GPS()
{


  num_sat = gps.satellites.value();

  if (gps.location.isValid() == 1) {

    Lat = gps.location.lat();
    Long = gps.location.lng();
    Alt = gps.altitude.meters();
    
    gps_speed = gps.speed.kmph();

    heading = gps.cardinal(gps.course.value());
  }



 /*   if (gps.date.isValid())
    {
      day = gps.date.day();
      month = gps.date.month();
      year = gps.date.year();
    }

  if (gps.time.isValid())
    {

      hour = gps.time.hour();
      minute = gps.time.minute();
      second = gps.time.second();
    }
*/

  smartDelay(1000);


  if (millis() > 5000 && gps.charsProcessed() < 10)
  {
    // Serial.println(F("No GPS detected: check wiring."));

  }



}

static void printDate(TinyGPSDate &d)
{
  if (!d.isValid())
  {
    u8g2.print(F("******** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d/%02d/%02d ", d.month(), d.day(), d.year());
    u8g2.print(sz);
  }
}
static void printTime(TinyGPSTime &t)
{  
  if (!t.isValid())
  {
    u8g2.print(F("******** "));
  }
  else
  {
    char sz[32];
    sprintf(sz, "%02d:%02d:%02d ", t.hour(), t.minute(), t.second());
    u8g2.print(sz);
  }

 // printInt(d.age(), d.isValid(), 5);
  smartDelay(0);
}

void print_Trip()
{
unsigned long distanceKm =
  (unsigned long)TinyGPSPlus::distanceBetween(
    gps.location.lat(),
    gps.location.lng(),
    Home_LAT,
    Home_LNG ) / 1000.0;
      u8g2.setFont(u8g2_font_nine_by_five_nbp_tf);
      u8g2.setCursor(0, 20);
      u8g2.print("Trip: ");
      u8g2.setCursor(50, 20);
      u8g2.print(distanceKm);
      u8g2.setCursor(90, 20);
      u8g2.print("Km");
      
double courseTo =
  TinyGPSPlus::courseTo(
    gps.location.lat(),
    gps.location.lng(),
    Home_LAT,
    Home_LNG );
      
      u8g2.setCursor(0, 30);
      u8g2.print("Course: ");
      u8g2.setCursor(60, 30);
      u8g2.print(courseTo);
      u8g2.setCursor(90, 30);
      u8g2.print("Km");

String cardinalTo = TinyGPSPlus::cardinal(courseTo);
      u8g2.setCursor(0, 40);
      u8g2.print("Cardinal: ");
      u8g2.setCursor(60, 40);
      u8g2.print(cardinalTo);

}

Prototype:

GPS Display Screens:

Working Video:

Downloads:

• Arduino IDE
• TinyGPS++ Library (tinygps2)
• OLED library u8glib2
• SoftwareSerial Library

1. MAX7219 8×8 LED Matrix
2. ESP8266 Node MCU
3. USB Cable for programming and power

Circuit Diagram:

Steps: 

1. 1. 1. Connect the circuit as shown above.
      2. Install Arduino IDE form arduino website. After that install ESP8266 board and library in Arduino IDE.
      3. Download and install MD_MAX7219 Library from download section for driving MAX7219 matrix. For using this library you will need to edit MAX72xx.h file for configure the type of LED matrix you are using. In this project we are using FC-16 Chinese module.
      4. Download code ino file from download section and open it with Arduino IDE.
      5. You will need to edit WiFi network SSID and Password inside your code before flashing it in ESP module.

         const char* ssid = "your SSID";                   // edit your wifi SSID here
         const char* password = "your Password";            // edit your wifi password here

      6. Select board to NodeMCU and flash the code in ESP module.
      7. Power up the circuit and you will see IP address of your ESP module allocated by your WiFi network on Matrix display. (watch video)

   
   
   

   1. Now open that IP address in any browser connected in same network. And you will see web user interface to enter text.
   2. For detailed procedure of configuring WiFi module with your home network and using web interface, please watch embedded YouTube video linked at the bottom of this page.

Code:

//Link: https://blog.etechpath.com

#include <ESP8266WiFi.h>
#include <MD_MAX72xx.h>
#include <SPI.h>

#define	PRINT_CALLBACK	0
#define DEBUG 0
#define LED_HEARTBEAT 0

#if DEBUG
#define	PRINT(s, v)	{ Serial.print(F(s)); Serial.print(v); }
#define PRINTS(s)   { Serial.print(F(s)); }
#else
#define	PRINT(s, v)
#define PRINTS(s)
#endif

#if LED_HEARTBEAT
#define HB_LED  D2
#define HB_LED_TIME 500 // in milliseconds
#endif

#define	MAX_DEVICES	4

#define	CLK_PIN		D5 // or SCK
#define	DATA_PIN	D7 // or MOSI
#define	CS_PIN		D8 // or SS

// SPI hardware interface
//MD_MAX72XX mx = MD_MAX72XX(CS_PIN, MAX_DEVICES);
#define HARDWARE_TYPE MD_MAX72XX::PAROLA_HW  //edit this as per your LED matrix hardware type
MD_MAX72XX mx = MD_MAX72XX(HARDWARE_TYPE, CS_PIN, MAX_DEVICES);
// Arbitrary pins
//MD_MAX72XX mx = MD_MAX72XX(DATA_PIN, CLK_PIN, CS_PIN, MAX_DEVICES);

// WiFi login parameters - network name and password
const char* ssid = "your SSID";                   // edit your wifi SSID here
const char* password = "your Password";            // edit your wifi password here

// WiFi Server object and parameters
WiFiServer server(80);

// Global message buffers shared by Wifi and Scrolling functions
const uint8_t MESG_SIZE = 255;
const uint8_t CHAR_SPACING = 1;
const uint8_t SCROLL_DELAY = 75;

char curMessage[MESG_SIZE];
char newMessage[MESG_SIZE];
bool newMessageAvailable = false;

char WebResponse[] = "HTTP/1.1 200 OK\nContent-Type: text/html\n\n";

char WebPage[] =
"<!DOCTYPE html>" \
"<html>" \
"<head>" \
"<title>eTechPath MAX7219 ESP8266</title>" \
"<style>" \
"html, body" \ 
"{" \
"width: 600px;" \
"height: 400px;" \
"margin: 0px;" \
"border: 0px;" \
"padding: 10px;" \
"background-color: white;" \
"}" \
"#container " \
"{" \
"width: 100%;" \
"height: 100%;" \
"margin-left: 200px;" \
"border: solid 2px;" \
"padding: 10px;" \
"background-color: #b3cbf2;" \
"}" \          
"</style>"\
"<script>" \
"strLine = \"\";" \
"function SendText()" \
"{" \
"  nocache = \"/&nocache=\" + Math.random() * 1000000;" \
"  var request = new XMLHttpRequest();" \
"  strLine = \"&MSG=\" + document.getElementById(\"txt_form\").Message.value;" \
"  request.open(\"GET\", strLine + nocache, false);" \
"  request.send(null);" \
"}" \
"</script>" \
"</head>" \
"<body>" \
"<div id=\"container\">"\
"<H1><b>WiFi MAX7219 LED Matrix Display</b></H1>" \ 
"<form id=\"txt_form\" name=\"frmText\">" \
"<label>Msg:<input type=\"text\" name=\"Message\" maxlength=\"255\"></label><br><br>" \
"</form>" \
"<br>" \
"<input type=\"submit\" value=\"Send Text\" onclick=\"SendText()\">" \
"<p><b>Visit Us at</b></p>" \ 
"<a href=\"http://www.eTechPath.com\">www.eTechPath.com</a>" \
"</div>" \
"</body>" \
"</html>";

char *err2Str(wl_status_t code)
{
  switch (code)
  {
  case WL_IDLE_STATUS:    return("IDLE");           break; // WiFi is in process of changing between statuses
  case WL_NO_SSID_AVAIL:  return("NO_SSID_AVAIL");  break; // case configured SSID cannot be reached
  case WL_CONNECTED:      return("CONNECTED");      break; // successful connection is established
  case WL_CONNECT_FAILED: return("CONNECT_FAILED"); break; // password is incorrect
  case WL_DISCONNECTED:   return("CONNECT_FAILED"); break; // module is not configured in station mode
  default: return("??");
  }
}
uint8_t htoi(char c)
{
  c = toupper(c);
  if ((c >= '0') && (c <= '9')) return(c - '0');
  if ((c >= 'A') && (c <= 'F')) return(c - 'A' + 0xa);
  return(0);
}
boolean getText(char *szMesg, char *psz, uint8_t len)
{
  boolean isValid = false;  // text received flag
  char *pStart, *pEnd;      // pointer to start and end of text
  // get pointer to the beginning of the text
  pStart = strstr(szMesg, "/&MSG=");
  if (pStart != NULL)
  {
    pStart += 6;  // skip to start of data
    pEnd = strstr(pStart, "/&");
    if (pEnd != NULL)
    {
      while (pStart != pEnd)
      {
        if ((*pStart == '%') && isdigit(*(pStart+1)))
        {
          // replace %xx hex code with the ASCII character
          char c = 0;
          pStart++;
          c += (htoi(*pStart++) << 4);
          c += htoi(*pStart++);
          *psz++ = c;
        }
        else
          *psz++ = *pStart++;
      }
      *psz = '\0'; // terminate the string
      isValid = true;
    }
  }
  return(isValid);
}
void handleWiFi(void)
{
  static enum { S_IDLE, S_WAIT_CONN, S_READ, S_EXTRACT, S_RESPONSE, S_DISCONN } state = S_IDLE;
  static char szBuf[1024];
  static uint16_t idxBuf = 0;
  static WiFiClient client;
  static uint32_t timeStart;

  switch (state)
  {
  case S_IDLE:   // initialise
    PRINTS("\nS_IDLE");
    idxBuf = 0;
    state = S_WAIT_CONN;
    break;
  case S_WAIT_CONN:   // waiting for connection
    {
      client = server.available();
      if (!client) break;
      if (!client.connected()) break;
#if DEBUG
      char szTxt[20];
      sprintf(szTxt, "%03d:%03d:%03d:%03d", client.remoteIP()[0], client.remoteIP()[1], client.remoteIP()[2], client.remoteIP()[3]);
      PRINT("\nNew client @ ", szTxt);
#endif
      timeStart = millis();
      state = S_READ;
    }
    break;
  case S_READ: // get the first line of data
    PRINTS("\nS_READ");
    while (client.available())
    {
      char c = client.read();
      if ((c == '\r') || (c == '\n'))
      {
        szBuf[idxBuf] = '\0';
        client.flush();
        PRINT("\nRecv: ", szBuf);
        state = S_EXTRACT;
      }
      else
        szBuf[idxBuf++] = (char)c;
    }
    if (millis() - timeStart > 1000)
    {
      PRINTS("\nWait timeout");
      state = S_DISCONN;
    }
    break;
  case S_EXTRACT: // extract data
    PRINTS("\nS_EXTRACT");
    // Extract the string from the message if there is one
    newMessageAvailable = getText(szBuf, newMessage, MESG_SIZE);
    PRINT("\nNew Msg: ", newMessage);
    state = S_RESPONSE;
    break;
  case S_RESPONSE: // send the response to the client
    PRINTS("\nS_RESPONSE");
    // Return the response to the client (web page)
    client.print(WebResponse);
    client.print(WebPage);
    state = S_DISCONN;
    break;
  case S_DISCONN: // disconnect client
    PRINTS("\nS_DISCONN");
    client.flush();
    client.stop();
    state = S_IDLE;
    break;

  default:  state = S_IDLE;
  }
}
void scrollDataSink(uint8_t dev, MD_MAX72XX::transformType_t t, uint8_t col)
// Callback function for data that is being scrolled off the display
{
#if PRINT_CALLBACK
  Serial.print("\n cb ");
  Serial.print(dev);
  Serial.print(' ');
  Serial.print(t);
  Serial.print(' ');
  Serial.println(col);
#endif
}
uint8_t scrollDataSource(uint8_t dev, MD_MAX72XX::transformType_t t)
// Callback function for data that is required for scrolling into the display
{
  static enum { S_IDLE, S_NEXT_CHAR, S_SHOW_CHAR, S_SHOW_SPACE } state = S_IDLE;
  static char		*p;
  static uint16_t	curLen, showLen;
  static uint8_t	cBuf[8];
  uint8_t colData = 0;
  // finite state machine to control what we do on the callback
  switch (state)
  {
  case S_IDLE: // reset the message pointer and check for new message to load
    PRINTS("\nS_IDLE");
    p = curMessage;      // reset the pointer to start of message
    if (newMessageAvailable)  // there is a new message waiting
    {
      strcpy(curMessage, newMessage); // copy it in
      newMessageAvailable = false;
    }
    state = S_NEXT_CHAR;
    break;
  case S_NEXT_CHAR: // Load the next character from the font table
    PRINTS("\nS_NEXT_CHAR");
    if (*p == '\0')
      state = S_IDLE;
    else
    {
      showLen = mx.getChar(*p++, sizeof(cBuf) / sizeof(cBuf[0]), cBuf);
      curLen = 0;
      state = S_SHOW_CHAR;
    }
    break;
  case S_SHOW_CHAR:	// display the next part of the character
    PRINTS("\nS_SHOW_CHAR");
    colData = cBuf[curLen++];
    if (curLen < showLen)
      break;
    // set up the inter character spacing
    showLen = (*p != '\0' ? CHAR_SPACING : (MAX_DEVICES*COL_SIZE)/2);
    curLen = 0;
    state = S_SHOW_SPACE;
    // fall through
  case S_SHOW_SPACE:	// display inter-character spacing (blank column)
    PRINT("\nS_ICSPACE: ", curLen);
    PRINT("/", showLen);
    curLen++;
    if (curLen == showLen)
      state = S_NEXT_CHAR;
    break;
  default:
    state = S_IDLE;
  }
  return(colData);
}
void scrollText(void)
{
  static uint32_t	prevTime = 0;
  // Is it time to scroll the text?
  if (millis() - prevTime >= SCROLL_DELAY)
  {
    mx.transform(MD_MAX72XX::TSL);	// scroll along - the callback will load all the data
    prevTime = millis();			// starting point for next time
  }
}
void setup()
{
#if DEBUG
  Serial.begin(115200);
  PRINTS("\n[MD_MAX72XX WiFi Message Display]\nType a message for the scrolling display from your internet browser");
#endif
#if LED_HEARTBEAT
  pinMode(HB_LED, OUTPUT);
  digitalWrite(HB_LED, LOW);
#endif
  // Display initialisation
  mx.begin();
  mx.setShiftDataInCallback(scrollDataSource);
  mx.setShiftDataOutCallback(scrollDataSink);
  curMessage[0] = newMessage[0] = '\0';
  // Connect to and initialise WiFi network
  PRINT("\nConnecting to ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED)
  {
    PRINT("\n", err2Str(WiFi.status()));
    delay(500);
  }
  PRINTS("\nWiFi connected");
  // Start the server
  server.begin();
  PRINTS("\nServer started");
  // Set up first message as the IP address
  sprintf(curMessage, "%03d:%03d:%03d:%03d", WiFi.localIP()[0], WiFi.localIP()[1], WiFi.localIP()[2], WiFi.localIP()[3]);
  PRINT("\nAssigned IP ", curMessage);
}
void loop()
{
#if LED_HEARTBEAT
  static uint32_t timeLast = 0;
  if (millis() - timeLast >= HB_LED_TIME)
  {
    digitalWrite(HB_LED, digitalRead(HB_LED) == LOW ? HIGH : LOW);
    timeLast = millis();
  }
#endif
  handleWiFi();
  scrollText();
}

Downloads:

1. Arduino IDE
2. ESP8266 Arduino Library
3. MajicDesigns MD_MAX7219 Library
4. Code.ino

Video:

How to solve mirror image and orientation problems of matrix display if you are using old MD_MAX72xx library.