Added logic to ask for ssid and password in the serial monitor

mqtt_send_receive_data.ino

@@ -0,0 +1,133 @@
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+
+// Update these with values suitable for your network.
+const char* ssid = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; //no need to edit here. Enter the SSID in the serial monitor
+const char* password = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"; //no need to edit here. Enter the password in the serial monitor
+const char* mqtt_server = "io.adafruit.com";
+#define mqtt_port 1883
+#define MQTT_USER "USER"
+#define MQTT_PASSWORD "PASSWORD"
+#define MQTT_SERIAL_PUBLISH_CH "USER/feeds/trial"
+#define MQTT_SERIAL_RECEIVER_CH "USER/feeds/ledBrightness"
+
+WiFiClient wifiClient;
+
+int wifiCredentials = 0;
+
+PubSubClient client(wifiClient);
+
+void setup_wifi() {
+    delay(10);
+    // We start by connecting to a WiFi network
+    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 reconnect() {
+  // Loop until we're reconnected
+  while (!client.connected()) {
+    Serial.print("Attempting MQTT connection...");
+    // Create a random client ID
+    String clientId = "NodeMCUClient-";
+    clientId += String(random(0xffff), HEX);
+    // Attempt to connect
+    if (client.connect(clientId.c_str(),MQTT_USER,MQTT_PASSWORD)) {
+      Serial.println("connected");
+      //Once connected, publish an announcement...
+      client.publish(MQTT_SERIAL_PUBLISH_CH, "hello world");
+      // ... and resubscribe
+      client.subscribe(MQTT_SERIAL_PUBLISH_CH);
+    } else {
+      Serial.print("failed, rc=");
+      Serial.print(client.state());
+      Serial.println(" try again in 5 seconds");
+      // Wait 5 seconds before retrying
+      delay(5000);
+    }
+  }
+}
+
+
+void callback(char* topic, byte *payload, unsigned int length) {
+    Serial.println("-------new message from broker-----");
+    Serial.print("channel:");
+    Serial.println(topic);
+    Serial.print("data:");  
+    //Serial.write(48);  
+    Serial.write(payload, length);
+    if(*payload == 'O' && *(payload+1)== 'N')
+    {
+      digitalWrite(13, HIGH);
+    }
+    else
+    {
+      digitalWrite(13, LOW);
+    }
+}
+
+void setup() {
+  Serial.begin(115200);
+  pinMode(13, OUTPUT);
+  digitalWrite(13, LOW);
+  Serial.setTimeout(500);// Set time out for 
+  getCredentials(); 
+
+    setup_wifi();
+    client.setServer(mqtt_server, mqtt_port);
+    client.setCallback(callback);
+    delay(1000);
+    reconnect();
+  //setup_wifi();
+  //client.setServer(mqtt_server, mqtt_port);
+  //client.setCallback(callback);
+  //reconnect();
+
+}
+
+void getCredentials()
+{
+    Serial.println("Enter the Wifi Name:");
+    while(!Serial.available());
+    char ssidbfr[50];
+    memset(ssidbfr,0, 50);
+    Serial.readBytesUntil( '\n',ssidbfr,50);
+    ssid = ssidbfr;
+    Serial.println(ssid);
+
+    Serial.println("Enter the Wifi Password:");
+    while(!Serial.available());
+    char passbfr[50];
+    memset(passbfr,0, 50);
+    Serial.readBytesUntil( '\n',passbfr,50);
+    password = passbfr;
+    Serial.println(password);
+}
+
+void publishSerialData(char *serialData){
+  if (!client.connected()) {
+    reconnect();
+  }
+  client.publish(MQTT_SERIAL_PUBLISH_CH, serialData);
+}
+void loop() {
+   client.loop();
+     if (Serial.available() > 0) {
+     char bfr[101];
+     memset(bfr,0, 101);
+     Serial.readBytesUntil( '\n',bfr,100);
+     publishSerialData(bfr);
+   }
+ }