mosquitto_pub and mosquitto_sub commands in IOT Protocols - Mini Project: Build & Apply

Using mosquitto_pub and mosquitto_sub Commands

📖 Scenario: You are working with MQTT, a messaging protocol used in IoT devices. You want to send and receive messages using the mosquitto_pub and mosquitto_sub commands on your local machine.This project will guide you through publishing a message to a topic and subscribing to that topic to receive the message.

🎯 Goal: Learn how to use the mosquitto_pub command to publish a message to a topic and the mosquitto_sub command to subscribe and receive messages from that topic.

📋 What You'll Learn

Have Mosquitto client tools installed (mosquitto_pub and mosquitto_sub)

Use the local MQTT broker at localhost

Publish a message to a topic named home/temperature

Subscribe to the topic home/temperature to receive messages

💡 Why This Matters

🌍 Real World

MQTT is widely used in IoT devices to send sensor data like temperature or humidity to a central server or cloud.

💼 Career

Knowing how to use mosquitto_pub and mosquitto_sub commands is essential for IoT developers and DevOps engineers working with MQTT-based systems.

1

Create the MQTT topic name

Create a variable called topic and set it to the string "home/temperature".

IOT Protocols

# Create a variable called topic and set it to "home/temperature"
# Your code here

Need a hint?

The topic is a string that identifies the message channel. Use quotes around the topic name.

2

Create the message to publish

Create a variable called message and set it to the string "22.5" representing the temperature value.

IOT Protocols

topic = "home/temperature"
# Create a variable called message and set it to "22.5"
# Your code here

Need a hint?

The message is the data you want to send. Use quotes around the number as a string.

3

Write the mosquitto_pub command

Create a variable called publish_command and set it to the string that runs mosquitto_pub to publish the message to the topic on the local broker. The command should be: mosquitto_pub -h localhost -t home/temperature -m 22.5.

IOT Protocols

topic = "home/temperature"
message = "22.5"
# Create a variable called publish_command with the mosquitto_pub command string
# Your code here

Need a hint?

Use an f-string to insert the topic and message variables into the command string.

4

Write the mosquitto_sub command and print both commands

Create a variable called subscribe_command and set it to the string that runs mosquitto_sub to subscribe to the topic on the local broker. The command should be: mosquitto_sub -h localhost -t home/temperature. Then print both publish_command and subscribe_command on separate lines.

IOT Protocols

topic = "home/temperature"
message = "22.5"
publish_command = f"mosquitto_pub -h localhost -t {topic} -m {message}"
# Create subscribe_command with mosquitto_sub command string
# Print publish_command and subscribe_command
# Your code here

Need a hint?

Use an f-string for the subscribe_command. Use two print statements to show both commands.