modular-weather-station/WeatherStation.ino

/*
 * ModularWeatherStation
 *
 * Copyright (C) 2021 Gergely Polonkai
 * Author: Gergely POLONKAI <gergely@polonkai.eu>
 *
 * ModularWeatherStation is free software: you can redistribute it
 * and/or modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * ModularWeatherStation is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * As additional permission under GNU GPL version 3 section 7, you may
 * distribute non-source form of the Program without the copy of the
 * GNU GPL normally required by section 4, provided you inform the
 * receipents of GNU GPL by a written offer.
 *
 */

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <ESP8266mDNS.h>
#include <ESP8266WebServer.h>

#include "config.h"

#ifdef DHT_TYPE
# include <DHT.h>
#endif // DHT_TYPE

ESP8266WebServer server(80);
unsigned long last_update = 0;

#ifdef DHT_TYPE
DHT dht(DHT_PIN, DHT_TYPE);
float temperature = 0.0;
float humidity = 0.0;
#endif // DHT_TYPE

static const char TEXT_PLAIN[] PROGMEM = "text/plain";

void
reply_not_found()
{
    server.send(404, FPSTR(TEXT_PLAIN), "Not Found");
}

void
send_metrics()
{
    static const size_t dht_size = 228;
    char message[dht_size + 1];

    size_t message_size =
#ifdef DHT_TYPE
        dht_size +
#endif // DHT_TYPE
        1;

    snprintf(message, message_size,
#ifdef DHT_TYPE
             "# HELP temperature_celsius Temperature in degrees Celsius\n"
             "# TYPE temperature_celsius gauge\n"
             "temperature_celsius %.2f\n"
             "# HELP relative_humidity Relative humidity, in percents\n"
             "# TYPE relative_humidity gauge\n"
             "relative_humidity %.2f\n",
             temperature, humidity
#endif // DHT_TYPE
        );

    server.send(200, "text/plain; version=0.0.4; charset=utf-8", message);
}

void
setup()
{
    IPAddress address;

    Serial.begin(9600);

    WiFi.mode(WIFI_STA);
    WiFi.begin(WIFI_SSID, WIFI_PASS);

    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.println("Waiting for WiFi to connect...");
    }

    address = WiFi.localIP();
    Serial.print("WiFi Address: ");
    address.printTo(Serial);
    Serial.println("");

    if (!MDNS.begin(MDNS_NAME)) {
        Serial.println("Error setting up mDNS responder!");

        while (1) {
            delay(1000);
        }
    }

    server.on("/metrics", HTTP_GET, send_metrics);
    server.onNotFound(reply_not_found);

    server.begin();

    MDNS.addService("http", "tcp", 80);

    // Initialize sensors
#ifdef DHT_TYPE
    dht.begin();
#endif // DHT_TYPE

    Serial.println("All set, starting the loop.");
}

void
read_sensors()
{
    // Turn on the LED to indicate that we’re working
    digitalWrite(LED_BUILTIN, LOW);

#ifdef DHT_TYPE
    temperature = dht.readTemperature();
    humidity = dht.readHumidity();
#endif

    // Turn off the LED to indicate work is finished
    digitalWrite(LED_BUILTIN, HIGH);
}

void
loop()
{
    unsigned long now = millis();

    MDNS.update();
    server.handleClient();

    if (now - last_update >= 5000) {
        read_sensors();

        last_update = now;
    }
}