4-Digit 7 Segment LED Display & MQTT

Software:

• Arduino IDE(version 1.6.4+)
• ESP8266 Board Package and the Serial Port Driver
• MQTT Client(MQTTBox here)
• Arduino library: PubSubClient
• Arduino library: TM1637

Connection

NodeMCU	4 digital display
3.3V	VCC
GND	GND
D2	CLK
D3	DIO

/*  

 * Recive the data published by the MQTT client and display it on the 4-digital display

 * Tutorial URL 

 * CopyRight www.osoyoo.com

 */

#include <ESP8266WiFi.h>

#include <PubSubClient.h>

#include <TM1637Display.h>

// Update these with values suitable for your network.

//const char* ssid = "*******";//put your wifi ssid here

const char* ssid = "PTS-2F";//put your wifi ssid here

//const char* password = "*******";//put your wifi password here

const char* password = "" ;//put your wifi password here

const char* mqtt_server = "broker.mqttdashboard.com";

//const char* mqtt_server = "iot.eclipse.org";

const int CLK = D2; //Set the CLK pin connection to the display

const int DIO = D3; //Set the DIO pin connection to the display

TM1637Display display(CLK, DIO); //set up the 4-Digit Display.

WiFiClient espClient;

PubSubClient client(espClient);

long lastMsg = 0;

char msg[50];

int value = 0;

void setup_wifi() {

   delay(100);

  // We start by connecting to a WiFi network

    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("Command from MQTT broker is : [");

  Serial.print(topic);

   Serial.println();

  Serial.print(" publish data is:");

  for(int i=0;i<length;i++)

  {

    display.showNumberDec((char)payload[i],false,4,0); //Display the numCounter value;

    Serial.print(payload[i]);

  }

  Serial.println();

} //end callback

void reconnect() {

  // Loop until we're reconnected

  while (!client.connected()) 

  {

    Serial.print("Attempting MQTT connection...");

    // Create a random client ID

    String clientId = "ESP8266Client-";

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

    // Attempt to connect

    //if you MQTT broker has clientID,username and password

    //please change following line to    if (client.connect(clientId,userName,passWord))

    if (client.connect(clientId.c_str()))

    {

      Serial.println("connected");

     //once connected to MQTT broker, subscribe command if any

      client.subscribe("Alex9ufo4DisplayCommand");

      

     // client.subscribe("OsoyooCommand");

     //• Topic to publish: OsoyooCommand

     //• Payload Type: Decimal Array

    } else {

      Serial.print("failed, rc=");

      Serial.print(client.state());

      Serial.println(" try again in 5 seconds");

      // Wait 6 seconds before retrying

      delay(6000);

    }

  }

} //end reconnect()

void setup() {

  Serial.begin(115200);

  setup_wifi();

  client.setServer(mqtt_server, 1883);

  display.setBrightness(0x0a); //set the diplay to maximum brightness

}

void loop() {

  if (!client.connected()) {

    reconnect();

  }

  client.setCallback(callback);

  client.loop();

}