Arduino.ru

        #include <SoftwareSerial.h> 
        #include <SD.h>
        SoftwareSerial mySerial(2, 3); //сюда gps модуль 
        File GPS;
        char buf[128];
        byte bufSize;
        bool waiting = true;
        void setup() {
         delay(800);
         pinMode(4, OUTPUT);
         while (!SD.begin()) {
          digitalWrite(4,HIGH); delay(100);
          digitalWrite(4,LOW); delay(100);
          digitalWrite(4,HIGH); delay(100);
          digitalWrite(4,LOW); delay(300);
         }
         GPS = SD.open("LOG.GPS", FILE_WRITE);
         if (!GPS)
          while (true) { 
           digitalWrite(4,HIGH); delay(100);
           digitalWrite(4,LOW); delay(100);
           digitalWrite(4,HIGH); delay(100);
           digitalWrite(4,LOW); delay(300);
          }
         mySerial.begin(9600); // скорость GPS порта
         Serial.begin(57600); //скорость порта 
         digitalWrite(4,HIGH);
        }
        void loop() {
         digitalWrite(4,LOW);
         while (mySerial.available()) {
         bufSize = mySerial.readBytesUntil('\n', buf, 128);
         if (waiting) {
          if (bufSize > 70) {
           waiting = false;
           GPS.write(buf, bufSize);
           Serial.println(buf); 
          }
         } else if (bufSize > 0) {
          GPS.write(buf, bufSize);
          Serial.println(buf);
          digitalWrite(4,HIGH);
         }
         GPS.flush();
        }