test.cpp

#include <ESP8266WiFi.h>          // Simple Libary for Wifi AP to use
const char WiFiAPPSK[] = "xxx";   // Set Wifi Password
const char AP_NameChar[] = "xxx"; // Set Wifi Name

#include <Hash.h>              // Used for webserver
#include <ESPAsyncTCP.h>       // Used for webserver
#include <ESPAsyncWebServer.h> // Used for webserver
#include <FS.h>                // Used for webserver
AsyncWebServer server(80);     // Create AsyncWebServer object on port 80

#include <Wire.h>            //Used for temp etc
#include <SPI.h>             //Used for temp etc
#include <Adafruit_BMP280.h> //Used for temp etc

Adafruit_BMP280 bmp;

String _jsonDocument;

SensorData_t sensorData;

void createJSONDocument(float temp, float humidity, float pressure)
{
    char buffer[100];
    snprintf(buffer, sizeof(buffer), "{\"temp\": %f, \"humidity\": %f, \"pressure\": %f}", temp, humidity, pressure);
    _jsonDocument = buffer;
}

void readBME280()
{
    float t = bmp.readTemperature();
    float p = bmp.readPressure();
    float h = bmp.readHumidity();

    if (!isnan(t) && !isnan(p) && !isnan(h))
    {
        Serial.println(t);
        createJSONDocument(t, h, p);
        return;
    }

    Serial.println("Failed to read from BME280 sensor!");
}

void setup()
{

    Serial.begin(9600); // Start Serial Interface
    unsigned status;
    status = bmp.begin(0x76);
    if (!SPIFFS.begin())
    {
        Serial.println("An Error has occurred while mounting SPIFFS");
        return;
    }
    WiFi.mode(WIFI_AP);                  // Start the Access point
    WiFi.softAP(AP_NameChar, WiFiAPPSK); // Set the name and password from above

    /* Default settings from datasheet. */
    bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,     /* Operating Mode. */
                    Adafruit_BMP280::SAMPLING_X2,     /* Temp. oversampling */
                    Adafruit_BMP280::SAMPLING_X16,    /* Pressure oversampling */
                    Adafruit_BMP280::FILTER_X16,      /* Filtering. */
                    Adafruit_BMP280::STANDBY_MS_500); /* Standby time. */

    // Route for root / web page
    server.on("/", HTTP_GET, [](AsyncWebServerRequest *request)
              { request->send(SPIFFS, "/index.html"); });
    server.on("/highcharts.js", HTTP_GET, [](AsyncWebServerRequest *request)
              { request->send(SPIFFS, "/highcharts.js", "text/javascript"); });
    server.on("/data.json", HTTP_GET, [](AsyncWebServerRequest *request)
              { request->send_P(200, "text/plain", _jsonDocument); });

    // Start server
    server.begin();
}

void loop()
{
    readBME280();
}