send_hello_wifi.ino

#include <ESP8266WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>

const char* ssid          = "****";
const char* wifi_password = "****";
const char* mqtt_server   = "****";
const int   port          = ****;
const char* username      = "****";
const char* password      = "****";

WiFiClient espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  setupWifi();
  client.setServer(mqtt_server, port);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
  client.publish("key", "hello");
  Serial.print("publish ed");
  delay(1000);
}

void setupWifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, wifi_password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("1-go-ki", username, password)) {
      Serial.println("connected");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

MQTTでメッセージ送信