Connect MQTT with NodeMCU 8266

my_mqtt.ino

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


const char* ssid = "ssid_name";
const char* password = "ssid_password";
const char* mqtt_server = "broker.emqx.io";
const char mqtt_username[50] = "";
const char mqtt_password[50] = "";
const int mqtt_port = 1883;

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[10];  // 0 off, 1 on
int value = 0;
int cnt = 0;

void setup_wifi() {
  delay(10);

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

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, LOW);
    value = 1;
  } else {
    value = 0;
    digitalWrite(BUILTIN_LED, HIGH);
  }
}

void reconnect() {

  while (!client.connected()) {
    Serial.print("Attempting MQTT connection…");

    String clientId = "ESP8266Client - ";
    clientId += String(random(0xffff), HEX);

    // client.connect(clientId.c_str(), mqtt_username, mqtt_password)
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      client.publish("mychn1234/in", "Start Programe");
      client.subscribe("mychn1234/out");
    } else {
      Serial.print("failed, rc = ");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, HIGH);
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}



void loop() {
  delay(5000);
  if (!client.connected()) {
    Serial.println("Cannot connect to MQTT");
    reconnect();
    delay(5000);
  }
  client.loop();

  ++cnt;
  if (cnt % 10 == 0) {
    value = 0;
    digitalWrite(BUILTIN_LED, HIGH);
  }
  Serial.print("Value from LOOP");
  Serial.println(value);
  snprintf (msg, 2, "%ld", value);
  Serial.print("Publish message: ");
  Serial.println(msg);
  client.publish("mychn1234/in", msg);


}

my_mqtt_detect.ino

// สำหรับส่งสัญญาณจากการ detect ระดับน้ำจากแทงค์

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

#define D1 5
#define button D1


const char* ssid = "ssid_name";
const char* password = "password";
const char* mqtt_server = "broker.emqx.io";
const char mqtt_username[50] = "";
const char mqtt_password[50] = "";
const int mqtt_port = 1883;

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[10];  // 0 off, 1 on
int value = 0;
int cnt = 0;

void setup_wifi() {
  delay(10);

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

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, LOW);
    value = 1;
  } else {
    value = 0;
    digitalWrite(BUILTIN_LED, HIGH);
  }
}

void reconnect() {

  while (!client.connected()) {
    Serial.print("Attempting MQTT connection…");

    String clientId = "ESP8266Client - ";
    clientId += String(random(0xffff), HEX);

    // client.connect(clientId.c_str(), mqtt_username, mqtt_password
    if (client.connect(clientId.c_str())) { //ทำการ Connect โดยใช้ Username&Password
      Serial.println("connected");
      client.publish("mychn77882/out", "hello world from 2");
    } else {
      Serial.print("failed, rc = ");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  pinMode(button, INPUT_PULLUP);
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, HIGH);
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}



void loop() {
  delay(5000);
  if (!client.connected()) {
    Serial.println("Cannot connect to MQTT");
    reconnect();
    delay(5000);
  }
  client.loop();

  bool readSwitch = digitalRead(button);
  value = 0;
  if (readSwitch == LOW) {
    value = 1;
    Serial.println("Pressed Switch");
    delay(500);
  }
  
  Serial.print("Value from LOOP");
  Serial.println(value);
  snprintf (msg, 2, "%ld", value);
  Serial.print("Publish message: ");
  Serial.println(msg);
  client.publish("mychn77882/out", msg);


}

my_mqtt_switch.ino

// สำหรับต่อกับ switch ใช้สั่งงาน on / off

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


const char* ssid = "ssid_name";
const char* password = "password";
const char* mqtt_server = "broker.emqx.io";
const char mqtt_username[50] = "";
const char mqtt_password[50] = "";
const int mqtt_port = 1883;

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[10];  // 0 off, 1 on
int value = 0;
int cnt = 0;

void setup_wifi() {
  delay(10);

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

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, LOW);
    value = 1;
  } else {
    value = 0;
    digitalWrite(BUILTIN_LED, HIGH);
  }
}

void reconnect() {

  while (!client.connected()) {
    Serial.print("Attempting MQTT connection…");

    String clientId = "ESP8266Client - ";
    clientId += String(random(0xffff), HEX);

    // client.connect(clientId.c_str(), mqtt_username, mqtt_password
    if (client.connect(clientId.c_str())) { //ทำการ Connect โดยใช้ Username&Password
      Serial.println("connected");
      client.subscribe("mychn77882/out");
    } else {
      Serial.print("failed, rc = ");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);
  digitalWrite(BUILTIN_LED, HIGH);
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}



void loop() {
  delay(5000);
  if (!client.connected()) {
    Serial.println("Cannot connect to MQTT");
    reconnect();
    delay(5000);
  }
  client.loop();

}