【GP-02-Kit】GPS Clock

This article introduces the project design process of creating a GPS clock using the Ai-Thinker GP-02-Kit development board with Arduino IDE, authored by Wuyin de Guangmiao.

Hardware Connection

• OLED_SCL → 14
• OLED_SDA → 02
• GP-02-Kit_RX → 04
• GP-02-Kit_TX → 05

Code Explanation

#include <TinyGPSPlus.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <SoftwareSerial.h>
#include <ESP8266WiFi.h>
// I2C Connection Instructions
// NodeMCU Development Board — 0.96" OLED Pin Mapping
// GND → GND
// 3V3 → VCC
// SCL → D1 (GPIO 5)
// SDA → D2 (GPIO 4)
#define SCREEN_WIDTH 128 // OLED display width
#define SCREEN_HEIGHT 64 // OLED display height
#define OLED_SDA 02 // SDA pin, GPIO2 (D4)
#define OLED_SCL 14 // SCL pin, GPIO14 (D5)
#define OLED_RESET 13 // Reset pin
#define SCREEN_ADDRESS 0x3C // OLED display I2C address
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
// GPS module pin definitions
#define RXPin 4 // GPIO12 (NodeMCU D6)
#define TXPin 5 // GPIO14 (NodeMCU D5)
SoftwareSerial ss(RXPin, TXPin);
TinyGPSPlus gps;
int Year, Month, Date, Hour, Minute, Second, Yea, Mon, Dat, Hou;
double Lat, Lng;
String sMonth, sDate, sHour, sMinute, sSecond;
void setup() {
Wire.begin(OLED_SDA, OLED_SCL);
Serial.begin(9600);
WiFi.mode(WIFI_OFF); // Disable WiFi to save power
WiFi.forceSleepBegin();
ss.begin(9600); // Initialize virtual serial port for GPS
if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
Serial.println(F("SSD1306 allocation failed"));
for (;;);
}
display.clearDisplay();
display.setTextColor(WHITE);
display.display();
}
void loop() {
boolean newData = false;
for (unsigned long start = millis(); millis() - start < 300;) {
while (ss.available()) {
if (gps.encode(ss.read())) {
newData = true;
}
}
}
Yea = gps.date.year();
Mon = gps.date.month();
Dat = gps.date.day();
Hou = gps.time.hour();
Minute = gps.time.minute();
Second = gps.time.second();
Lng = gps.location.lng();
Lat = gps.location.lat();
// Convert UTC time to Beijing time and correct errors
Hour = Hou + 8;
if (Hour >= 24) {
Hour -= 24;
}
if (Hou + 8 >= 24) {
Date = Dat + 1;
if ((Mon == 1 || Mon == 3 || Mon == 5 || Mon == 7 || Mon == 8 || Mon == 10 || Mon == 12) && (Date > 31)) {
Date -= 30;
Month = Mon + 1;
} else if ((Mon == 4 || Mon == 6 || Mon == 9 || Mon == 11) && (Date > 30)) {
Date -= 29;
Month = Mon + 1;
} else if ((Yea % 4 == 0) && (Date > 29)) {
Date -= 28;
Month = Mon + 1;
} else if ((Yea % 4 != 0) && (Date > 28)) {
Date -= 27;
Month = Mon + 1;
} else {
Month = Mon;
Year = Yea;
}
if (Month > 12) {
Month -= 12;
Year = Yea + 1;
}
} else {
Date = Dat;
Month = Mon;
Year = Yea;
}
// Display the results
display.setTextColor(SSD1306_WHITE);
display.setCursor(38, 0);
display.setTextSize(1);
display.print(Year);
display.setCursor(63, 0);
display.print("-");
display.setCursor(71, 0);
sMonth = formatNumber(Month, 2);
display.print(sMonth);
display.setCursor(83, 0);
display.print("-");
display.setCursor(91, 0);
sDate = formatNumber(Date, 2);
display.print(sDate);
display.setTextSize(2);
display.setCursor(26, 13);
sHour = formatNumber(Hour, 2);
display.print(sHour);
display.setCursor(46, 13);
display.print(":");
display.setCursor(56, 13);
sMinute = formatNumber(Minute, 2);
display.print(sMinute);
display.setCursor(76, 13);
display.print(":");
display.setCursor(86, 13);
sSecond = formatNumber(Second, 2);
display.print(sSecond);
display.setTextSize(1);
display.setCursor(35, 33);
display.print(gps.location.lng(), 8);
display.setCursor(35, 43);
display.print(gps.location.lat(), 8);
display.setCursor(105, 53);
display.print("m");
display.setCursor(50, 53);
display.print("km/h");
display.setCursor(80, 53);
display.print(gps.speed.mps());
display.setCursor(25, 53);
display.print(gps.speed.kmph());
display.display();
delay(500);
display.clearDisplay();
}
// Helper function to format numbers
String formatNumber(int number, int digits) {
String formatted = "";
if (number < pow(10, digits - 1)) {
formatted = String(number, DEC);
while (formatted.length() < digits) {
formatted = "0" + formatted;
}
} else {
formatted = String(number, DEC);
}
return formatted;
}

Schematic Diagram

Outcome

Place the antenna outdoors or by a window to maintain connection.After powering up, it takes about 30 seconds for the module to start receiving and displaying clock, coordinates, and speed information.

For more details about the development board, visit the LCSC Open Source Hardware Platform.

OLED Display

Conclusion

This article introduced the design process for creating a GPS clock using the Ai-Thinker GP-02-Kit development board, providing a reference for further development and applications based on the GP-02 module.