Hackster is hosting Hackster Holidays, Ep. 6: Livestream & Giveaway Drawing. Watch previous episodes or stream live on Monday!Stream Hackster Holidays, Ep. 6 on Monday!
Dhairya Parikh
Published © GPL3+

Running a MQTT Broker on Raspberry Pi

This project gives you an overview on MQTT and helps you setup a mosquitto MQTT server on a Raspberry Pi. We will send some Dummy data too.

BeginnerProtip1 hour18,106
Running a MQTT Broker on Raspberry Pi

Things used in this project

Hardware components

Raspberry Pi 3 Model B
Raspberry Pi 3 Model B
This will host the MQTT Broker
×1
NodeMCU ESP8266 Breakout Board
NodeMCU ESP8266 Breakout Board
This will act as a MQTT Node and will publish the Sensor Data.
×1

Software apps and online services

Arduino IDE
Arduino IDE
Programming the Node MCU
Raspbian
Raspberry Pi Raspbian
MQTT
MQTT

Story

Read more

Code

NodeMCU_MQTT

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

// Update these with values suitable for your network.

const char* ssid = "tpdefault";
const char* password = "manas12345";
const char* mqtt_server = "192.168.225.39";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE	(50)
char msg[MSG_BUFFER_SIZE];
int value = 0;

void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  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();

  // Switch on the LED if an 1 was received as first character
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, LOW);   // Turn the LED on (Note that LOW is the voltage level
    // but actually the LED is on; this is because
    // it is active low on the ESP-01)
  } else {
    digitalWrite(BUILTIN_LED, HIGH);  // Turn the LED off by making the voltage HIGH
  }

}

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 (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("outTopic", "hello world");
      // ... and resubscribe
      client.subscribe("inTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void loop() {

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

  unsigned long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    ++value;
    snprintf (msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
    Serial.print("Publish message: ");
    Serial.println(msg);
    client.publish("outTopic", msg);
  }
}

Credits

Dhairya Parikh

Dhairya Parikh

21 projects • 123 followers
Project Developer | IoT and Machine Learning Enthusiast | Open Source Enthusiast |

Comments

Related channels and tags
  • Espressif
  • Internet of Things
  • Internet of Things
  • MQTT
  • NodeMCU
  • Raspberry Pi