Raspberry Pi with MQTT Broker and Displaying Sensor Data on Node-RED Dashboard

In this tutorial, we will set up a Raspberry Pi as an MQTT broker, collect sensor data using an ESP8266 with a DHT11 sensor, and display the data on a Node-RED dashboard. MQTT (Message Queuing Telemetry Transport) is a lightweight messaging protocol ideal for IoT applications due to its low power usage and minimal bandwidth consumption. Hope you like this tutorial on Raspberry Pi with MQTT Broker and Displaying Sensor Data on Node-RED.

Components Required

1. Raspberry Pi (any model with Wi-Fi connection)
2. ESP8266 (NodeMCU)
3. DHT11 temperature and humidity sensor
4. Jumper wires
5. Breadboard (optional)

Working

Below is the working of this project

Setting Up ESP8266 with DHT11 Sensor

Wiring the DHT11 to ESP8266

• Connect the VCC pin of DHT11 to the 3.3V pin of ESP8266.
• Connect the GND pin of DHT11 to the GND pin of ESP8266.
• Connect the DATA pin of DHT11 to a digital pin (e.g., D4) of ESP8266.

Configuring Arduino IDE

First download the Arduino IDE from the official website. After installing follow the below steps.

Install ESP8266 Board in Arduino IDE: Open Arduino IDE, go to File > Preferences and add the following URL to the Additional Boards Manager URLs field:

Then go to Tools > Board > Boards Manager, search for esp8266, and install it.

Install Required Libraries: Go to Sketch > Include Library > Manage Libraries, search for and install the following libraries:

• • DHT sensor library by Adafruit
  • PubSubClient by Nick O’Leary

Code

You can download the code from the given link and upload it in your nodeMCU. We have an illustrated tutorial that can help you in doing this.

Upload the code to the ESP8266. Make sure to select the correct board and port from the Tools menu.

Setting Up Raspberry Pi as MQTT Broker

Install Raspberry Pi OS

• Download Raspberry Pi OS from the official Raspberry Pi website.
• Use Raspberry Pi Imager or balenaEtcher to flash the OS image to your microSD card.
• Once the OS is flashed, enable SSH and configure Wi-Fi by creating `ssh` and `wpa_supplicant.conf` files in the boot partition of the SD card.

Boot and Update Raspberry Pi

• Insert the microSD card into the Raspberry Pi and power it on.
• Use an SSH client (like PuTTY) to connect to the Raspberry Pi.
• Login to Raspberry Pi and update the system by executing the below commands one after another.

sudo apt-get update

sudo apt-get upgrade

Installing MQTT

To install MQTT (Mosquitto), run the below command.

sudo apt install mosquitto mosquitto-clients

After installing MQTT Enable and start the MQTT service from below commands

sudo systemctl enable mosquitto

sudo systemctl start mosquitto

Go to sudo nano /etc/mosquitto/mosquitto.conf

Enter below lines, Save and exit.

listener 1883

allow_anonymous true

Installing Node-RED on Raspberry Pi

To install and run node-red on your raspberry pi, Use the below commands

sudo apt-get install -y nodejs npm

sudo npm install -g –unsafe-perm node-red

sudo systemctl enable nodered.service

sudo systemctl start nodered.service

Configuring Node-RED Dashboard

Installing Dashboard Nodes

In the Node-RED interface, go to the menu, select Manage palette, then click on Install and search for node-red-dashboard and Install it.

Creating a Flow

Access Node-RED:

• • Open a web browser and go to http://<your_raspberry_pi_ip>:1880.

Create a Flow in Node-RED:

• • Drag and drop an MQTT input node, a JSON node, and a debug node onto the workspace.
  • Configure the MQTT input node for Temperature:
    • Server: mqtt://localhost:1883
    • Topic: home/temperature (similarly for home/humidity)
  • Connect the nodes: MQTT input -> JSON -> Debug.
  • Add a gauge and connect it with JSON, configure it as shown below

Deploy the Flow:

• • Click the Deploy button to save and run the flow.
  • Open the debug panel to see the incoming messages.

Building and Testing

• Power up the NodeMCU and Raspberry Pi.
• Monitor the Serial Output: Open the Serial Monitor in Arduino IDE to see the debug messages from NodeMCU.
• Check Node-RED: Go to the Node-RED interface and observe the temperature and humidity data in the debug panel.

Viewing Data on Node-RED Dashboard

1. Access the Node-RED dashboard: Open your web browser and navigate to <http://RaspberryPi_IP>:1880/ui>
2. Monitor the data: You should see the real-time temperature and humidity data displayed on the dashboard.

Conclusion

In this tutorial, we successfully set up Raspberry Pi with MQTT Broker and Displaying Sensor Data on Node-RED, connected an ESP8266 with a DHT11 sensor to publish data, and displayed the sensor data on a Node-RED dashboard. This setup is highly scalable and can be extended to include multiple sensors and devices, making it a powerful solution for IoT projects.

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