와이파이와 MQTT기본 라이브러리 사용법

// 무선 공유기(AP,엑세스 포인트)의 이름과 비밀번호
#define AP_SSID  "my-ssid"
#define AP_PASS  "my-pass"
#include <ESP8266WiFi.h>

WiFiClient espClient;

void setup_wifi() { 
  delay(100);
  
  // WiFi station mode
  WiFi.mode(WIFI_STA);  
  WiFi.begin(AP_SSID,AP_PASS);   

  Serial.printf("\nConnecting to [%s]\n",AP_SSID);  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.print("\nConnected to [");
  Serial.print(WiFi.SSID());
  Serial.print("],IP=");
  Serial.println(WiFi.localIP());
}

typedef enum {
  WL_NO_SHIELD = 255,
  WL_IDLE_STATUS = 0,
  WL_NO_SSID_AVAIL = 1,
  WL_SCAN_COMPLETED = 2,
  WL_CONNECTED = 3,
  WL_CONNECT_FAILED = 4,
  WL_CONNECTION_LOST = 5,
  WL_DISCONNECTED = 6
} wl_status_t;

// 무선 공유기(AP,엑세스 포인트)의 이름과 비밀번호
#define AP_SSID1  "my-ssid1"
#define AP_PASS1  "my-pass1"

#define AP_SSID2  "my-ssid2"  // 없으면 ""
#define AP_PASS2  "my-pass2"  // 없으면 ""

#define AP_SSID3  "my-ssid3"  // 없으면 ""
#define AP_PASS3  "my-pass3"  // 없으면 ""

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>

WiFiClient espClient;
ESP8266WiFiMulti wifiMulti;

void setup_wifi() { 
  delay(100);
  
  // WiFi station mode
  WiFi.mode(WIFI_STA);  
  wifiMulti.addAP(AP_SSID1,AP_PASS1);
  wifiMulti.addAP(AP_SSID2,AP_PASS2);
  wifiMulti.addAP(AP_SSID3,AP_PASS3);

  Serial.printf("\nConnecting to [%s],[%s],[%s]\n",
                AP_SSID1,AP_SSID2,AP_SSID3);  
  while (wifiMulti.run() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.print("\nConnected to [");
  Serial.print(WiFi.SSID());
  Serial.print("],IP=");
  Serial.println(WiFi.localIP());
}

// MQTT 설정 
#define SERVER     "192.168.XXX.XXX"
#define PORT       1883

#define USER       "user"  
#define PASS       "yourPass"

#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
#include <PubSubClient.h>

WiFiClient espClient;
ESP8266WiFiMulti wifiMulti;
PubSubClient client;

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.println("Attempting MQTT connection...");
    String clientId = "ESP8266-";
    clientId += String(random(0xffff), HEX); 
    Serial.printf("SERVER=[%s],PORT=%d\n",SERVER,PORT);
    Serial.printf("device=[%s],USER=[%s],PASS=[***]\n",clientId.c_str(),USER);
    // Attempt to connect
    if (client.connect(clientId.c_str(),USER,PASS)) {
      Serial.println("MQTT connected\n-----");
      int QoS = 1;
      client.subscribe(TOPIC_LED,QoS);
      Serial.printf("SUB: [%s],[%d]\n",TOPIC_LED,QoS);
    } 
    else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

// Possible values for client.state()
#define MQTT_CONNECTION_TIMEOUT     -4
#define MQTT_CONNECTION_LOST        -3
#define MQTT_CONNECT_FAILED         -2
#define MQTT_DISCONNECTED           -1
#define MQTT_CONNECTED               0
#define MQTT_CONNECT_BAD_PROTOCOL    1
#define MQTT_CONNECT_BAD_CLIENT_ID   2
#define MQTT_CONNECT_UNAVAILABLE     3
#define MQTT_CONNECT_BAD_CREDENTIALS 4
#define MQTT_CONNECT_UNAUTHORIZED    5

void callback(char* topic, byte* payload, unsigned int length) {
  char newPayload[32];
  int newLength = length;
  if (newLength > 31 ) {
    newLength = 31;
  }

  Serial.print("RCV: [");
  Serial.print(topic);
  Serial.print("]");
  for (int i = 0; i < newLength; i++) {
    newPayload[i] = (char)payload[i];
  }
  newPayload[newLength] = '\0';
  Serial.print(",[");
  Serial.print(newPayload);
  Serial.println("]");

  String topicS = String(topic);
  String payloadS = String(newPayload);

  if (topicS == TOPIC_LED) {
    led.set(payloadS);
    client.publish(TOPIC_LED_R,payloadS.c_str(),true);
    Serial.printf("PUB: [%s],[%s]\n",topicS.c_str(),payloadS.c_str());
  }
}

void setup() {
  setup_wifi();
  client.setClient(espClient);
  client.setServer(SERVER,PORT);
  client.setCallback(callback);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}