The Internet of Things (IoT) redefines how we interact with technology. It is obvious that IoT bridges the gap between our physical and digital realm. Today, from smart home systems to adjusting lighting and temperature automatically to industrial sensors that monitor machinery in real time, IoT devices rule the roost. At the core of the Internet of Thing’s functionality is the smooth data exchange between devices. For this, one of the most commonly used protocols for device communication is MQTT (Message Queuing Telemetry Transport) or MQ Telemetry Transport.
In this blog, we shall explain MQTT in detail, its key applications, and the ways to configure an MQTT broker with Mosquitto. It further explores its capabilities with the ESP8266 Wi-Fi module.
MQTT, or Message Queuing Telemetry Transport, features a lightweight architecture created for low-bandwidth, high-latency, or unstable networks. Since it is lightweight, it is one of the most reliable ways to help devices send and receive messages. Its lightweight characteristic makes it a great protocol choice for IoT applications. It features a client-broker-server model, and the broker acts as the central hub. It manages message distribution between clients. In this MQTT system, there are essentially three significant roles:
Publisher: An application or a device that transmits information/messages to the broker on specific topics. Also, it provides information or commands to other devices.
Subscriber: A device or application that listens for messages on specific topics from the broker. It receives updates and commands from publishers.
Broker: The core component of the MQTT architecture. The broker receives and distributes messages from publishers to the appropriate subscribers. The distribution is done based on the topics they are interested in.
This architecture focuses on reliable communication among devices. Therefore, it makes MQTT suitable for Internet of Things (IoT) applications.
Manufacturing businesses make use of MQ Telemetry Transport to monitor equipment performance and maintenance needs.
MQTT medical devices help protect patient information and send them to healthcare service providers.
Using MQTT, farmers receive reports on soil conditions with the sensors in the field. Further, it helps them to streamline crop growth.
MQTT is ideal for vehicle fleet services, that it is easy to report location and status in real-time.
Smart grids in the energy industrial sector make use of MQ Telemetry Transport for efficient and better power distribution.
MQTT enables automation and control of devices such as lights, thermostats, and security systems.
The ESP8266 revolutionizes the world of the Internet of Things (IoT). This mighty chip (even though it is tiny) is fundamentally a replica of a minicomputer with built-in Wi-Fi features. Espressif Systems has created ESP8266. This module helps developers to connect devices to the internet wirelessly.
Further, it can communicate with various sensors and actuators. The ESP8266 serves as an ideal platform for building intelligent home automation systems, and other IoT applications. It is compatible with the Arduino IDE. Therefore, it is easy for both beginners and experienced developers to code and deploy projects successfully.
802.11 b/g/n support
The ESP8266 backs standard Wi-Fi protocols. Further, it makes ESP8266 work with home and industrial network.
Integrated TCP/IP stack
ESP8266 comes with an embedded TCP/IP stack. Therefore, it helps in direct communication with internet services.
Station/Soft Access Point mode
The module functions as a client (station) that connects to a router. Also, it works as an access point (AP) that other devices can connect to.
Tensilica Xtensa LX106 32-bit processor
The ESP8266 has a powerful core running at 80 MHz or 160 MHz. It makes ESP8266 ideal for processing lightweight tasks.
RAM
50 kB of available RAM, with 96 kB for data and instruction caching.
Flash Memory
The module features 512 kB to 4 MB of flash memory. It further enables the storage of larger programs and facilitates effortless firmware updates.
General-purpose Input/Output pins (GPIO)
The ESP8266 possesses up to 17 GPIO pins. These pins help to interface with sensors, relays, LEDs, and other peripherals.
The GPIO pins support PWM (Pulse Width Modulation), I2C, SPI, and UART protocols. It makes the module suitable for many hardware interfaces.
Low power consumption
The ESP8266 is optimized for low-power operation. It has several sleep modes (deep sleep, light sleep). Further, it provides energy utility when there is no active data transmission.
The ESP8266 operates at a voltage of 3.3V. It is needed when connecting to external components like sensors. An external power supply/voltage regulator might be needed when using 5V systems.
ADC (Analog to Digital Converter)
The ESP8266 includes a single 10-bit ADC. Therefore it allows the ESP8266 to read analog inputs from sensors, for example, temperature or light sensors.
UART
Serial communication is backed through the UART interface. It is useful for debugging and communicating data with other devices.
SPI and I2C
These serial communication protocols make it easy to interface with external hardware like displays, sensors, and storage devices.
WEP, WPA, and WPA2 Encryption
The module supports modern Wi-Fi encryption protocols. Additionally, it ensures the secure transmission of data.
TLS/SSL
Using libraries such as OpenSSL, the ESP8266 handles safe transfer of data over MQTT (FTPS, HTTPS). It is essential for IoT applications as data privacy is a priority.
The ESP8266 comes in several module formats. The most common are:
One of the most fundamental versions of ESP8266 with 2 GPIO pins and a small flash size. It is ideal for simple Wi-Fi applications.
A more advanced version with 17 GPIO pins, larger flash memory, and a built-in antenna.
A development board based on the ESP-12E/F module. It has a USB interface with built-in firmware and supports Arduino IDE or Lua scripting.
MQTT’s low bandwidth requirements help the ESP8266 to ensure reduced power consumption.
The ESP8266 maintains stable connections over MQTT that it offers smooth performance even in environments with unreliable and fluctuating network coverage.
Using MQ Telemetry Transport, the ESP8266 can communicate with multiple devices. Therefore, it becomes ideal for building scalable IoT networks.
MQTT backs real-time data transfer. As a result, it allows the ESP8266 to send and receive messages immediately.
The lightweight nature of MQTT helps the ESP8266 to communicate with the least delay. Therefore, it is most suitable for time-sensitive applications such as emergency notification systems and smart manufacturing solutions.
When combined with TLS/SSL, MQ Telemetry Transport ensures secure communication channel. It protects the exchange of sensitive information between the ESP8266 and the broker free from cyber threats.
1. Install Mosquitto MQTT Broker
sudo apt update
sudo apt install mosquitto mosquitto-clients
sudo systemctl enable mosquito
sudo systemctl start mosquitto
sudo nano /etc/mosquitto/mosquitto.conf
listener 1884
It will set the broker to listen on port 1884.
sudo systemctl restart mosquitto
sudo mosquitto_passwd -c /etc/mosquitto/passwd your_username
Replace your username with the desired username. Enter a password when you are asked to give the password
sudo nano /etc/mosquitto/mosquitto.conf
Add the following lines for authentication:
password_file /etc/mosquitto/passwd
allow_anonymous false
sudo systemctl restart mosquitto
Logging helps you monitor broker activities and fix issues through troubleshooting.
# Log to a file
log_dest file /var/log/mosquitto/mosquitto.log
# Log to the console
log_dest stdout
sudo mkdir -p /var/log/mosquitto
sudo chown mosquitto:mosquitto /var/log/mosquitto
sudo systemctl restart mosquitto
sudo cat /var/log/mosquitto/mosquitto.log
mosquitto_sub -h localhost -p 1884 -t “test/topic” -u your_username -P your_password
mosquitto_pub -h localhost -p 1884 -t “test/topic” -m “Welcome” -u your_username -P your_password
As a first step, prepare the Arduino IDE to work with the ESP8266 module:
Upload the basic example code for connecting our ESP8266 to a Wi-Fi network and an MQTT broker from PubSubClient GitHub Repository (http://bit.ly/4f8oKA4). The code helps subscribe to topics and receive messages.
Before uploading the code, make sure to replace the placeholders with your specific details:
We can create a simple system to control an LED light remotely using ESP8266 and MQTT to empower the Internet of Things (IoT).
In this setup, we use two ESP8266 devices: one device as a publisher to transmit commands to control the LED while the other as a subscriber to receive the commands and control the LED accordingly.
You can connect the publisher ESP8266 to a physical switch or a mobile app, allowing users to send messages to ‘switch on light’ or ‘switch off light’ to a specific topic, for example, “home/led/control.” The subscriber ESP8266 listens for these messages on the same topic. As soon as it receives a command from the user, it turns the LED on or off in accordance with the instruction.
In this system, the broker acts as the central hub. It handles smooth communication between the publisher and subscriber. Both ESP8266 devices connect to the broker, which offers flexible hosting- locally or on the cloud. It helps exchange messages without fail. After changing the LED’s state, the subscriber can publish a status update to another topic, such as “home/led/status.” It updates the user about the LED’s current state, that is if it is on or off. The two-way communication helps users control the LED from anywhere, anytime. Further, it translates to user convenience and what’s more enhances home automation.
Using MQTT with the ESP8266 sets the stage for creating smart, connected devices for the Internet of Things (IoT) ecosystem. Since it is lightweight in nature, it can efficiently handle communication over low-bandwidth networks. As a result, it is ideal for applications used for smart homes and industrial automation. We have discussed the fundamentals of MQ Telemetry Transport its key applications, and the configuration process for an MQTT broker using Mosquitto. Using MQTT’s reliable protocol establishes a strong foundation for further advancements, including tasks like sensor monitoring, remote device control, and developing more complex IoT systems.
At ThinkPalm our IoT specialists harness the endless potential of MQTT and ESP8266 to discover innovative solutions. With our wide expertise in IoT development, ThinkPalm helps businesses make the most of MQTT capabilities. It helps create scalable, fail-proof IoT solutions to empower businesses with the connected world.
Ashna N is an enthusiastic embedded engineer in the Wireless and Connectivity business unit, specializing in IoT solutions. With a solid foundation in electronics engineering, she is highly driven to discover and develop pioneering technologies that bridge the gap between devices and the digital world.
