esp8266_wifi_dht22.c

#include <ESP8266WiFi.h>
#include <MQTTClient.h>
#include "DHT.h"

const char *wifi_ssid     = "wifi";
const char *wifi_password = "secret";

const char *mqtt_server   = "broker.shiftr.io";
const char *mqtt_id       = "my_first_node";
const char *mqtt_user     = "login";
const char *mqtt_password = "secret";

const int  dht_pin        = D6;

WiFiClient net;
MQTTClient client;
DHT dht(dht_pin, DHT22);

void setup() {
  Serial.begin(115200);

  // wifi
  Serial.print("wifi: ssid=");
  Serial.println(wifi_ssid);
  Serial.print("wifi: password=");
  Serial.println(wifi_password);
  Serial.print("wifi: connecting");
  WiFi.begin(wifi_ssid, wifi_password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("wifi: ip_addr=");
  Serial.println(WiFi.localIP());
  Serial.println("wifi: done!");

  // message broker connection
  client.begin(mqtt_server, net);
  connect();
}

void connect() {
  Serial.print("mqtt: server=");
  Serial.println(mqtt_server);
  Serial.print("mqtt: id=");
  Serial.println(mqtt_id);
  Serial.print("mqtt: user=");
  Serial.println(mqtt_user);
  Serial.print("mqtt: password=");
  Serial.println(mqtt_password);
  Serial.print("mqtt: connecting");
  while (!client.connect(mqtt_id, mqtt_user, mqtt_password)) {
    Serial.print(".");
    delay(1000);
  }
  Serial.println();
  Serial.println("mqtt: done!");
  client.subscribe("commands");
}

void loop() {
  // vars
  float temperature = 0.0;
  float humidity = 0.0;
  String message;
 
  client.loop();
  delay(10); // stability fix
  if(!client.connected()) {
    connect();
  }


  temperature = dht.readTemperature();
  humidity = dht.readHumidity();
  message  = "temperature=";
  message += String(temperature, 1);
  message += " ";
  message += "humidity=";
  message += String(humidity, 1);  Serial.print("message_out: ");
  Serial.println(message);
  client.publish("sensors", message);

  delay(3000);
}

void messageReceived(String topic, String payload, char * bytes, unsigned int length) {
  Serial.print("message_in: topic=");
  Serial.print(topic);
  Serial.print(" payload='");
  Serial.print(payload);
  Serial.println("'");
}