festival_finder/20250815_basic_finder.ino/20250815_basic_finder.ino.ino

#include <U8g2lib.h>
#include <TinyGPSMinus.h>
#include <Wire.h>
#include <QMC5883LCompass.h>
#include "wifi_save.h"
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <config_secrets.h>


U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, /* reset=*/U8X8_PIN_NONE);  // if you use Hardware I2C port, full framebuffer, size = 1024 bytes
QMC5883LCompass compass;

#define RXD2 16
#define TXD2 17

#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;

byte triangles[][6] = {
  { 10, 48, 30, 48, 20, 16 },
  { 5, 43, 23, 51, 26, 17 },
  { 2, 36, 16, 50, 31, 21 },
  { 1, 29, 9, 47, 35, 26 },
  { 4, 22, 4, 42, 36, 32 },
  { 9, 17, 1, 35, 35, 38 },
  { 16, 14, 2, 28, 31, 43 },
  { 23, 13, 5, 21, 26, 47 },
  { 30, 16, 10, 16, 20, 48 },
  { 35, 21, 17, 13, 14, 47 },
  { 38, 28, 24, 14, 9, 43 },
  { 39, 35, 31, 17, 5, 38 },
  { 36, 42, 36, 22, 4, 32 },
  { 31, 47, 39, 29, 5, 26 },
  { 24, 50, 38, 36, 9, 21 },
  { 17, 51, 35, 43, 14, 17 },
  { 10, 48, 30, 48, 20, 16 }
};

void setup(void) {

  Serial.begin(115200);

  pinMode(LED_PIN, OUTPUT);

  if (wifi_set_main()) {
    Serial.println("Connect WIFI SUCCESS");
    connected = true;

  } else {

    digitalWrite(LED_PIN, LOW);
    Serial.println("Connect WIFI FAULT");
  }

  compass.init();

  u8g2.begin();  // start a display.
  gpsSerial.begin(GPS_BAUD, SERIAL_8N1, RXD2, TXD2);
  Serial.println("Serial 2 started at 9600 baud rate");




}

void drawTriangles(byte i, char *time, char *distanceString) {
  u8g2.clearBuffer();
  u8g2.drawTriangle(triangles[i][0], triangles[i][1], triangles[i][2], triangles[i][3], triangles[i][4], triangles[i][5]);
  u8g2.sendBuffer();
  u8g2.setFont(u8g2_font_helvR08_tr);
  u8g2.drawButtonUTF8(48, 64 - 40, U8G2_BTN_BW0, 0, 0, 0, "Last Update:");
  u8g2.drawButtonUTF8(48, 64 - 30, U8G2_BTN_BW0, 0, 0, 0, time);
  u8g2.drawButtonUTF8(48, 64 - 16, U8G2_BTN_BW0, 0, 0, 0, distanceString);
  u8g2.sendBuffer();
  delay(2000);
}

bool doHttpRequest(char *payload, char *latitude, char *longitude, char *gpsTime, char *az) {
  HTTPClient http;

  // Change space to 0
  if(*(latitude + 6) == ' ')
    *(latitude + 6) = '0';

  String serverPath = webserviceAddress + "?long=" + longitude + "&lat=" + latitude + "&id=" + OWN_ID + "&req_id=" + REQ_ID + "&gpsDateTime=" + gpsTime + "&passkey=" + SERVER_PASSKEY + "&az=" + az;

  Serial.println(serverPath);

  http.begin(serverPath.c_str());

  int httpResponseCode = http.GET();

  if (httpResponseCode == 200 ) {
    const char* cpayload = http.getString().c_str();
    strcpy(payload, cpayload);
    Serial.println(payload);
    return true;
  } else {
    Serial.print("Error code: ");
    Serial.println(httpResponseCode);
    return false;
  }
}

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;
  
  DeserializationError error = deserializeJson(doc, payload);

  if (error) {
    Serial.print(F("deserializeJson() failed: "));
    Serial.println(error.f_str());
    return;
  }

  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["azimuth"]).toFloat());
}



void loop(void) {
  checkWifiConnection();
  while (gpsSerial.available() > 0) {
    // get the byte data from the GPS
    char gpsData = gpsSerial.read();
    Serial.print(gpsData);
    if (gps.encode(gpsData)) {
      break;
    }
  }

  Serial.println();
  long unsigned date, time, age;
  char *longitude, *latitude, *dateTime;
  longitude = gps.get_longitude();
  latitude = gps.get_latitude();
  gps.get_datetime(&date, &time, &age);

  Serial.println(latitude);
  Serial.println(longitude);

  char myPayloadResponse[128];

  char timeString[10], dateString[10], dateTimeString[24], azString[11];
  ltoa(time, timeString, 10);
  ltoa(date, dateString, 10);
//  for (int i = 0; i < 18; i++) {
//    if (i < 7) {
//      dateTimeString[i] = dateString[i];
//    } else {
//      dateTimeString[i] = timeString[i - 8];
//    }
//  }

  strcpy(dateTimeString, dateString);
  strcat(dateTimeString, timeString);


  byte triangleIndex = 0;
  char distanceArray[] = { 'N', 'o', ' ', 'S', 'e', 'r', 'v', 'e', 'r', '\0' };
  char distanceString[16];
  strcpy(distanceString, distanceArray);

  char remoteTimeString[16];
  strcpy(remoteTimeString, timeString);

  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(1000);


}