Documentation

// Library Manager: install "TinyGPSPlus"
#include <TinyGPSPlus.h>
#include <SoftwareSerial.h>

SoftwareSerial gpsSerial(4, 3);  // RX = D4 (GPS TXD), TX = D3
TinyGPSPlus gps;

void setup() {
  Serial.begin(9600);
  gpsSerial.begin(9600);
  Serial.println("Waiting for GPS fix...");
}

void loop() {
  while (gpsSerial.available()) {
    gps.encode(gpsSerial.read());
  }

  if (gps.location.isUpdated()) {
    Serial.print("Lat: ");
    Serial.print(gps.location.lat(), 6);
    Serial.print("  Lng: ");
    Serial.print(gps.location.lng(), 6);
    Serial.print("  Sats: ");
    Serial.println(gps.satellites.value());
  }
}

#include <TinyGPSPlus.h>

TinyGPSPlus gps;
HardwareSerial gpsSerial(2);   // UART2

void setup() {
  Serial.begin(115200);
  gpsSerial.begin(9600, SERIAL_8N1, 16, 17);  // RX=16, TX=17
}

void loop() {
  while (gpsSerial.available()) {
    gps.encode(gpsSerial.read());
  }

  if (gps.location.isUpdated()) {
    Serial.printf("Lat: %.6f  Lng: %.6f  Sats: %lu  Alt: %.1f m\n",
                  gps.location.lat(), gps.location.lng(),
                  gps.satellites.value(), gps.altitude.meters());
  }
}

import serial
import pynmea2

# One-time setup:
#   sudo raspi-config > Interface Options > Serial Port
#   login shell: No / hardware serial: Yes
#   pip3 install pyserial pynmea2

port = serial.Serial("/dev/serial0", baudrate=9600, timeout=1)

while True:
    line = port.readline().decode("ascii", errors="replace").strip()
    if line.startswith("$GNGGA") or line.startswith("$GPGGA"):
        msg = pynmea2.parse(line)
        print(f"Lat: {msg.latitude:.6f}  Lng: {msg.longitude:.6f}  "
              f"Sats: {msg.num_sats}  Alt: {msg.altitude} m")

from machine import UART, Pin
import time

# GPS TXD -> GP1 (UART0 RX), GPS RXD -> GP0 (UART0 TX)
uart = UART(0, baudrate=9600, tx=Pin(0), rx=Pin(1))

def to_degrees(raw, hemi):
    """NMEA ddmm.mmmm to decimal degrees."""
    if not raw:
        return None
    dot = raw.find(".")
    degrees = float(raw[:dot - 2])
    minutes = float(raw[dot - 2:])
    value = degrees + minutes / 60
    if hemi in ("S", "W"):
        value = -value
    return value

buf = b""
while True:
    if uart.any():
        buf += uart.read()
        while b"\n" in buf:
            line, buf = buf.split(b"\n", 1)
            text = line.decode("ascii", "ignore").strip()
            if text.startswith("$GNGGA") or text.startswith("$GPGGA"):
                p = text.split(",")
                if p[6] != "0" and p[2]:   # fix quality > 0
                    lat = to_degrees(p[2], p[3])
                    lng = to_degrees(p[4], p[5])
                    print("Lat:", lat, " Lng:", lng, " Sats:", p[7])
    time.sleep(0.05)