Send azimuth + configurable bearing correction

From this change on, the client adds its azimuth measurement
to the get paramters, so the server can do the correction.

Also the response parameter for locally correcting bearing
according to azimuth measurements is respected.

Some comments from copy paste stuff were deleted.

20250815_basic_finder.ino/20250815_basic_finder.ino.ino

@@ -17,8 +17,11 @@ QMC5883LCompass compass;
 #define GPS_BAUD 9600
 
 String webserviceAddress = "https://festival-finder.noe-danke.de/updateGPS";
+String serverAvailableAddress = "https://festival-finder.noe-danke.de/";
 bool connected = false;
 
+bool use_bearing_correction = true;
+
 HardwareSerial gpsSerial(2);
 TinyGPSMinus gps;
 
@@ -81,30 +84,21 @@ void drawTriangles(byte i, char *time, char *distanceString) {
   delay(2000);
 }
 
-bool doHttpRequest(char *payload, char *latitude, char *longitude, char *gpsTime) {
+bool doHttpRequest(char *payload, char *latitude, char *longitude, char *gpsTime, char *az) {
   HTTPClient http;
+
   // Change space to 0
- 
+  if(*(latitude + 6) == ' ')
-  
-  if(*(latitude + 6) < '0' || *(latitude + 6) > '9')
     *(latitude + 6) = '0';
 
-  String serverPath = webserviceAddress + "?long=" + longitude + "&lat=" + latitude + "&id=" + OWN_ID + "&req_id=" + REQ_ID + "&gpsDateTime=" + gpsTime + "&passkey=" + SERVER_PASSKEY;
+  String serverPath = webserviceAddress + "?long=" + longitude + "&lat=" + latitude + "&id=" + OWN_ID + "&req_id=" + REQ_ID + "&gpsDateTime=" + gpsTime + "&passkey=" + SERVER_PASSKEY + "&az=" + az;
 
   Serial.println(serverPath);
 
-  // Your Domain name with URL path or IP address with path
   http.begin(serverPath.c_str());
 
-  // If you need Node-RED/server authentication, insert user and password below
-  //http.setAuthorization("REPLACE_WITH_SERVER_USERNAME", "REPLACE_WITH_SERVER_PASSWORD");
-
-  // Send HTTP GET request
   int httpResponseCode = http.GET();
 
-  Serial.print("HTTP Response code: ");
-  Serial.println(httpResponseCode);
-
   if (httpResponseCode == 200 ) {
     const char* cpayload = http.getString().c_str();
     strcpy(payload, cpayload);
@@ -117,13 +111,35 @@ bool doHttpRequest(char *payload, char *latitude, char *longitude, char *gpsTime
   }
 }
 
+void checkWifiConnection() {
+  HTTPClient http;
+  http.begin(serverAvailableAddress);
+  int httpResponseCode = http.GET();
+
+  Serial.print("Server availablity test response code: ");
+  Serial.println(httpResponseCode);
+
+  if (httpResponseCode == 200) {
+    digitalWrite(LED_PIN, HIGH);
+  } else {
+    digitalWrite(LED_PIN, LOW);
+  }
+}
+
 byte calculateBearing(float bearing) {
+  if(!use_bearing_correction) {
+    int iBearing = bearing;
+    return compass.getBearing(iBearing);
+  }
+
   compass.read();
   int relativeAngle = (int)(bearing - compass.getAzimuth());
   relativeAngle += 360;
   relativeAngle %= 360;
   return (compass.getBearing(relativeAngle) + BEARING_CORRECTION + 16) % 16;
 }
+
+
 void setDistanceBearingString(char *time, char *distance, byte *bearing, const char *payload) {
   StaticJsonDocument<200> doc;
   
@@ -137,21 +153,18 @@ void setDistanceBearingString(char *time, char *distance, byte *bearing, const c
 
   const char* dist2 = doc["distance"];
   const char* time2 = doc["lastUpdateTZ"];
+  use_bearing_correction = doc["bear_correction"];
+
   strcpy(distance, dist2);
   strcpy(time, time2);
 
-  *bearing = calculateBearing(String(doc["bearing"]).toFloat());
+  *bearing = calculateBearing(String(doc["azimuth"]).toFloat());
 }
 
 
 
 void loop(void) {
-  if(connected) {
+  checkWifiConnection();
-    digitalWrite(LED_PIN, HIGH);
-  }
-  else {
-    digitalWrite(LED_PIN, LOW);
-  }
   while (gpsSerial.available() > 0) {
     // get the byte data from the GPS
     char gpsData = gpsSerial.read();
@@ -171,9 +184,9 @@ void loop(void) {
   Serial.println(latitude);
   Serial.println(longitude);
 
-  char myPayloadResponse[80];
+  char myPayloadResponse[128];
 
-  char timeString[10], dateString[10], dateTimeString[24];
+  char timeString[10], dateString[10], dateTimeString[24], azString[11];
   ltoa(time, timeString, 10);
   ltoa(date, dateString, 10);
 //  for (int i = 0; i < 18; i++) {
@@ -187,6 +200,7 @@ void loop(void) {
   strcpy(dateTimeString, dateString);
   strcat(dateTimeString, timeString);
 
+
   byte triangleIndex = 0;
   char distanceArray[] = { 'N', 'o', ' ', 'S', 'e', 'r', 'v', 'e', 'r', '\0' };
   char distanceString[16];
@@ -195,14 +209,18 @@ void loop(void) {
   char remoteTimeString[16];
   strcpy(remoteTimeString, timeString);
 
-  if (doHttpRequest(myPayloadResponse, latitude, longitude, dateTimeString))
+  compass.read();
+  int az = compass.getAzimuth();
+  sprintf(azString, "%ld", az);
+
+  if (doHttpRequest(myPayloadResponse, latitude, longitude, dateTimeString, azString))
     setDistanceBearingString(remoteTimeString, distanceString, &triangleIndex, myPayloadResponse);
 
   drawTriangles(triangleIndex, remoteTimeString, distanceString);
 
   Serial.println("-------------------------------");
 
-  delay(3000);
+  delay(1000);
 
 
 }