simple ardunio projects

FIRST device PUBLISH data #include <WiFi.h> #include "Adafruit_MQTT.h" #include "Adafruit_MQTT_Client.h" #define AIO_SERVER      "io.adafruit.com" #define AIO_SERVERPORT  1883 #define AIO_USERNAME  "suresh7799" #define AIO_KEY  "6d84f0c9edca4461a7212d74c6099175" WiFiClient client; Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY); boolean MQTT_connect(); boolean MQTT_connect() {   int8_t ret;   if (mqtt.connected()) {     return true; }     uint8_t retries = 3;     while ((ret = mqtt.connect()) != 0) {       mqtt.disconnect();       delay(2000);       Serial.println("conneting to mqtt");       retries--;       if (retries == 0)       {         Serial.println("time out for mqtt");         return false; }}   ...

WiFi connections key words   1. WiFi.status();    Syntax:        while ((!(WiFi.status() == WL_CONNECTED))){        Serial.print("..");     delay(300);   }  2. WiFi.localIP()    Syntax:      WiFi.localIP() #include <WiFi.h> void setup() { Serial.begin(9600);   WiFi.begin("ssid","password");   Serial.println("Start");   Serial.print("please wait connecting to WIFI");   while ((!(WiFi.status() == WL_CONNECTED))){        Serial.print("..");     delay(300);   }   Serial.println("connected ");   Serial.println("IP address :");   Serial.print((WiFi.localIP())); } Result Server creation steps and client  1. WiFiSever sever(80);  port creation in WiFi making esp as sever and ip address as a client 2, WiFiClient client ;   creating client to WiFi  3....