What is ESP32 in IoT?

Discover the complete guide to ESP32 with detailed pinout, specifications, and project ideas. Learn how to use ESP32 for embedded systems, automation, smart devices, and real-time applications. Ideal for developers, engineers, and students looking for fast and efficient IoT development. Unlock the power of ESP32 in your next smart project.

Jul 22, 2025

Microcontroller

556 words

Device Overview

What is ESP32?

ESP32 is a powerful, low-cost, low-power microcontroller board developed by Espressif Systems. It comes with integrated Wi-Fi, Bluetooth, and a dual-core processor, making it a perfect choice for modern IoT (Internet of Things) and embedded applications. It is the successor of the popular ESP8266 board but offers much more processing power, GPIOs, and peripherals.

Key Features of ESP32

Processor: Dual-core Tensilica LX6 @ up to 240 MHz
Wi-Fi: IEEE 802.11 b/g/n
Bluetooth: v4.2 BR/EDR and BLE
GPIO Pins: 34 programmable I/O pins
Flash Memory: Typically 4MB (up to 16MB)
RAM: 520KB SRAM + External RAM supported
Operating Voltage: 3.3V
ADC Channels: 12-bit (up to 18 channels)
DAC Channels: 2 (8-bit)
PWM: Supported on all GPIOs
Touch Sensor Support: Up to 10 touch inputs
SPI, I2C, UART, CAN, I2S support for interfacing
Ultra Low Power (ULP) Co-processor for low-power applications

ESP32 Board Types

Board Name	Description
ESP32-WROOM-32	Most commonly used, built-in antenna, general-purpose
ESP32-WROVER	Includes external PSRAM, great for camera/audio processing
ESP32-S2	Single-core with improved security features
ESP32-C3	RISC-V-based, compact and power-efficient
ESP32-S3	Dual-core with AI instructions and USB OTG support
NodeMCU-32S	Developer-friendly with USB interface
TTGO T-Display	Built-in LCD screen, battery support

ESP32 Pinout (Basic Reference)

Power Pins: 3V3, GND, EN
Digital I/O: GPIO0 – GPIO39
Analog Input: GPIO32–39 (ADC1), GPIO0, 2, 4, 12–15, 25–27 (ADC2)
PWM Output: All digital pins
UART: GPIO1, GPIO3 (default), others configurable
SPI/I2C: User-defined (via software libraries)

Note: Some GPIOs are input-only or reserved during boot (e.g., GPIO6–11 used for flash memory).

Why Use ESP32?

Built-in Wi-Fi & Bluetooth – no need for external modules
Faster than Arduino & ESP8266
Supports advanced features like touch, DAC, CAN
Ideal for IoT, home automation, wearable tech, and industrial monitoring
Excellent community support & Arduino IDE compatibility

Programming ESP32

ESP32 can be programmed using:

Arduino IDE
ESP-IDF (Espressif IoT Development Framework)
PlatformIO
MicroPython

Popular libraries:

WiFi.h for Wi-Fi
BluetoothSerial.h for Bluetooth
ESPAsyncWebServer.h for web-based control
Adafruit_Sensor.h and others for interfacing

Real-Life IoT Example Project: Light ON/OFF Using ESP32 and Relay

Components Required

ESP32-WROOM-32
5V Relay Module
Light Bulb or LED
220V AC Supply (for bulb) or 5V DC (for LED)
Jumper wires, Breadboard

Circuit Diagram (Basic Overview)

ESP32 GPIO (e.g., GPIO 23) ---> Relay IN
ESP32 GND --------------------> Relay GND
ESP32 3.3V -------------------> Relay VCC
Relay COM & NO ---> AC Bulb or LED

Code Example (Using Arduino IDE)

#define RELAY_PIN 23

void setup() {
    pinMode(RELAY_PIN, OUTPUT);
    digitalWrite(RELAY_PIN, LOW); // Keep light OFF initially
    Serial.begin(115200);
}

void loop() {
    digitalWrite(RELAY_PIN, HIGH); // Light ON
    delay(5000);
    digitalWrite(RELAY_PIN, LOW);  // Light OFF
    delay(5000);
}

Output:

Light turns ON for 5 seconds and then OFF for 5 seconds in a loop.

Applications of ESP32

Home Automation Systems
Wi-Fi/Bluetooth based IoT Devices
Smart Sensors & Data Loggers
Agricultural Automation
Industrial Monitoring
Audio Processing Systems
AI on the Edge (ESP32-S3)

Advantages of ESP32

Integrated connectivity (Wi-Fi + BT)
Cost-effective
Versatile GPIO
Wide range of applications
Support for OTA (Over-The-Air updates)
Secure (HTTPS, SSL/TLS support)

Limitations of ESP32

Requires 3.3V logic level
Some GPIOs are boot-sensitive
Slightly complex for beginners vs Arduino Uno
High current draw during Wi-Fi transmission

Where to Buy

Platform	Price	Action
Amazon	₹479	Buy Now

Prices may vary. Click on "Buy Now" to check current availability and pricing.

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Frequently Asked Questions

Common questions about What is ESP32 in IoT?. Find answers to the most frequently asked questions.

ESP32 is used for developing wireless communication-based embedded systems. It supports Wi-Fi and Bluetooth, making it ideal for applications like automation, sensors, and smart devices.

Yes, ESP32 offers better speed, built-in Wi-Fi and Bluetooth, more GPIOs, and additional features compared to basic Arduino boards, making it more powerful for modern embedded applications.

Absolutely. ESP32 is fully compatible with the Arduino IDE after installing the ESP32 board package, making development easy for both beginners and experienced developers.

ESP32 is more advanced than ESP8266, offering dual-core CPU, Bluetooth support, more GPIOs, and better power management, while ESP8266 is limited to single-core and Wi-Fi only.

Yes, ESP32 supports both Bluetooth Classic and BLE (Bluetooth Low Energy), allowing it to connect with a wide range of Bluetooth-enabled devices and applications.

ESP32 typically runs on 3.3V. You can power it using a 5V USB supply via onboard voltage regulator, but direct connection to more than 3.3V on GPIO pins may damage the board.

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