[!C] New Class for sd writer

LoRaSender/LoRaSender.ino

@@ -5,6 +5,7 @@
 #include <Adafruit_SSD1306.h>
 #include <TinyGPS++.h>
 
+#include "SDCardHelper.ino"
 
 // LORA Settings
 #define SYNC_WORD 0xCE
@@ -29,9 +30,13 @@
 #define SCREEN_HEIGHT 64
 #define OLED_RESET -1
 
+#define SD_CS 13
+
 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
 TinyGPSPlus gps;
 
+SDHelper logger(SD_CS, FAM_W);
+
 void sendMessage(const String& msg) {
   LoRa.beginPacket();
   LoRa.write(SYNC_WORD);
@@ -68,16 +73,6 @@ bool getPacket(String& payload, byte& id) {
   return (payload.length() == len);
 }
 
-/*
-bool waitForAck(unsigned long timeout_ms = 1000) {
-  if (!waitForPacket(timeout_ms)) return false;
-  String payload;
-  byte snd;
-  if (!getPacket(payload, snd)) return false;
-  return (snd == RECEIVER_ID && payload == "ACK");
-}
-*/
-
 void showOnOLED(const String& line1, const String& line2 = "", const String& line3 = "", const String& line4 = "") {
   display.clearDisplay();
   display.setTextSize(1);
@@ -119,6 +114,11 @@ void SerialPrintGPS(){
   Serial.println("");
 }
 
+void storeToSD(const String& lat, const String& lng){
+  static int i = 1;
+  logger.Log(String(i++) + ": " + lat + " " + lng);
+}
+
 void setup() {
   Serial.begin(115200);
   Serial2.begin(_BAUDRATE_GPS, SERIAL_8N1, _RX_GPS, _TX_GPS);
@@ -178,6 +178,7 @@ void loop() {
       Serial.println("Sende GPS:\n" + lat_str + "\n" + lng_str);
       showOnOLED("Sende GPS Koords:", lat_str, lng_str, satellites);
 
+      storeToSD(lat_str, lng_str);
       sendMessage(lat_str + "\n\n" + lng_str + "\n\n" + satellites);
     }
   }

LoRaSender/SDCardHelper.ino

@@ -0,0 +1,58 @@
+#include <SPI.h>
+#include <SD.h>
+
+typedef enum{ 
+  FAM_R, 
+  FAM_W 
+} FileAccessMode;
+
+class SDHelper {
+private:
+  uint8_t _cs;
+  FileAccessMode _fam;
+  File _stream;
+  String _filename;
+  bool _available = false;
+  SPIClass _spi(HSPI);
+
+  String getNewFilename() {
+    static unsigned long i = 0;
+    String name;
+    do {
+      name = "coords" + String(i++) + ".txt";
+    } while (SD.exists(name.c_str()));
+    return name;
+  }
+
+public:
+  SDHelper(uint8_t csPin, FileAccessMode fam, String filename = "") : _cs(csPin), _fam(fam) {
+    _spi.begin(14, 2, 15, 13);
+    if(!SD.begin(_cs, _spi)){ 
+      _available = false; 
+      return;
+    }
+
+    if(_fam == FAM_W){
+      _filename = filename.length() ? filename : getNewFilename();
+      _stream = SD.open(_filename.c_str(), FILE_WRITE);
+    } 
+    else {
+      _filename = filename;
+      _stream = SD.open(_filename.c_str(), FILE_READ);
+    }
+    _available = (bool)_stream;
+  }
+
+  ~SDHelper(){ 
+    if(_stream) _stream.close();
+  }
+
+  bool Available() const { return _available; }
+  const String& filename() const { return _filename; }
+
+  void Log(const String& msg) {
+    if(_fam != FAM_W || !_stream) return;
+    _stream.println(msg);
+    _stream.flush();
+  }
+};