ESP32 MQTT Publisher and Subscriber
An ESP32-based project demonstrating MQTT publish and subscribe communication for real-time IoT data exchange.
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₹7032.00
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Components
5 items
Difficulty
Intermediate
Build Time
1.5 – 2.5 hours
Project Details
How It Works
How It WorksThe project uses the MQTT publish/subscribe architecture. ESP32 devices connect to a Wi-Fi network and then to an MQTT broker. The publisher ESP32 sends messages to specific topics (e.g., 'home/esp32/temperature'). The broker routes these messages to all subscribers listening to those topics. The subscriber ESP32 receives the messages and can trigger actions like turning on an LED or relay. This creates a real-time, bidirectional communication system ideal for IoT applications.
Prerequisites
Basic knowledge of Arduino programming, understanding of Wi-Fi networking concepts, familiarity with C++ syntax, and access to an MQTT broker (public or private).
What You'll Learn
What You'll LearnUnderstanding publish/subscribe messaging model and QoS levels
Learning how publishers, brokers, and subscribers interact
Configuring ESP32 for Wi-Fi and network communication
Implementing instant data exchange between devices
Setting up and using MQTT brokers for IoT applications
Key Features
MQTT protocol has minimal overhead, ideal for constrained IoT devices
Supports thousands of devices and topics in a single network
Built-in QoS levels ensure message delivery guarantees
Works with both public cloud brokers and private local installations
What's Included in the Kit
| Component | Qty | Price |
|---|---|---|
 | 2 | ₹3363.00₹1682.00 × 2 |
 | 1 | ₹0.00 |
 | 1 | ₹189.00 |
 | 10 | ₹1711.00₹171.00 × 10 |
 | 1 | ₹0.00 |
Operating Instructions
Pin Connections
Pin Connections| MCU Pin | Connected To | Purpose | Notes |
|---|---|---|---|
| GPIO 2 | LED (+ resistor) | Digital output for subscriber to control LED based on received messages | Optional for subscriber demonstration |
| GND | LED (–) | Ground connection for LED | Optional for subscriber demonstration |
Tools Required
Tools RequiredSafety Precautions
Electrical
- ⚠Ensure proper power supply voltage (3.3V for ESP32)
- ⚠Avoid short circuits when connecting components
- ⚠Use appropriate current limiting for LEDs and relays
Operating
- ⚠Do not expose ESP32 to moisture or extreme temperatures
- ⚠Handle components with care to avoid static damage
Security
- ⚠Use authentication for MQTT brokers in production
- ⚠Enable TLS (MQTTS) for encrypted communication
- ⚠Avoid public brokers for sensitive data
- ⚠Use strong, unique topic naming conventions
Frequently Asked Questions
Frequently Asked QuestionsQ:Can one ESP32 be both publisher & subscriber?
Q:Can this work with Home Assistant?
Q:Is MQTT better than HTTP for IoT?
Q:What's the difference between QoS levels?
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