The ESP32-WROOM-32E Dual Relay Development Board combines an ESP32 WiFi/Bluetooth microcontroller with 2 onboard 5V relays, providing a compact solution for smart home automation, IoT control, wireless switching, robotics, and custom embedded projects.

Based on the ESP32-WROOM-32E module with 4MB Flash, the board exposes the ESP32 I/O and UART programming connections for secondary development. It also includes programmable controls, status indicators, and a wide 7-60V DC power input range, making it convenient for integration into automation systems.

Key Features

• ESP32-WROOM-32E module
• 4MB Flash memory
• Built-in WiFi connectivity
• Built-in Bluetooth connectivity
• 2 onboard 5V relays
• Wide 7-60V DC power input
• ESP32 I/O connections exposed
• UART programming interface exposed
• IO0 programmable/boot button
• Reset button
• Programmable onboard LED
• Relay status indicators
• Supports Arduino IDE development
• Suitable for secondary development
• Compact integrated design
• Ideal for IoT and smart home projects

ESP32-WROOM-32E

The board uses the mature ESP32-WROOM-32E wireless microcontroller module.

It combines processing, WiFi, Bluetooth, GPIO, serial communication, and other embedded capabilities in a single platform, making it suitable for standalone and connected control applications.

4MB Flash Memory

The ESP32 module includes:

4MB Flash Memory

This provides storage for firmware, libraries, configuration data, and application code.

Dual Relay Outputs

The board integrates 2 × 5V relays, allowing the ESP32 to directly control two independent switching channels.

The relays provide switch outputs suitable for controlling compatible electrical loads.

Specified maximum switching voltages:

• AC Load Voltage: Up to 250V AC
• DC Load Voltage: Up to 30V DC

The maximum relay contact current was not provided in the supplied specifications and should be verified from the relay markings before connecting high-current loads.

Wide 7-60V DC Input

The development board supports a wide input voltage range:

7-60V DC

This makes it easier to integrate into systems operating from common DC supplies such as:

• 12V systems
• 24V systems
• 36V systems
• 48V systems

Always verify correct input polarity before applying power.

WiFi & Bluetooth Control

Because the board is based on the ESP32 platform, it can be programmed for wireless control applications using WiFi or Bluetooth.

Possible projects include:

• Smartphone-controlled switches
• Web-based relay control
• WiFi automation
• MQTT control
• IoT dashboards
• Home automation
• Remote equipment control
• Sensor-triggered switching

The exact wireless functionality depends on the firmware developed and installed by the user.

Arduino IDE Support

The ESP32 supports development using the popular Arduino IDE environment with the appropriate ESP32 board package installed.

This allows developers to use the large Arduino ecosystem of libraries and examples when creating custom applications.

Development Interfaces

The ESP32 I/O and UART programming connections are exposed to make custom development and expansion easier.

Available development features include:

• ESP32 GPIO access
• UART programming connections
• IO0 programmable/boot button
• Reset button
• Programmable LED
• Relay control outputs

This makes the board suitable for both learning and custom embedded product development.

Status Indicators

The board includes visual indicators for easier development and troubleshooting:

• Programmable LED
• Relay status indicators

These can help monitor relay activation and program status during development.

Technical Specifications

• Product Type: ESP32 Dual Relay Development Board
• Main Module: ESP32-WROOM-32E
• Flash Memory: 4MB
• Wireless: WiFi & Bluetooth
• Relay Channels: 2
• Relay Coil Voltage: 5V
• Maximum Specified AC Switching Voltage: 250V AC
• Maximum Specified DC Switching Voltage: 30V DC
• Relay Contact Current: Not Specified
• Board Power Input: 7-60V DC
• Programming Interface: UART
• GPIO Access: Yes
• IO0 Button: Yes
• Reset Button: Yes
• Programmable LED: Yes
• Relay Indicators: Yes
• Development Environment: Arduino IDE Compatible
• Application Type: IoT / Automation / Wireless Control / Development

Typical Applications

• Smart home automation
• WiFi relay control
• Bluetooth relay control
• IoT projects
• Remote equipment control
• Lighting automation
• Pump control
• Fan control
• Alarm systems
• Access control projects
• Industrial prototypes
• Robotics
• ESP32 development
• MQTT projects
• Web-controlled switches
• Sensor-based automation
• DIY electronics
• Educational projects

Example Applications

The board can be programmed to create systems such as:

WiFi Control

Smartphone / Computer → WiFi → ESP32 → Relay → Load

Sensor Automation

Sensor → ESP32 → Control Logic → Relay → Device

IoT Control

Cloud / MQTT Server → WiFi → ESP32 → Relay → Equipment

Actual implementation depends on the firmware and connected hardware.

Important Relay Safety Note

The supplied specifications state that the relays can switch loads with working voltages up to 250V AC or 30V DC, but the maximum relay contact current is not specified.

Before connecting a load:

• Check the relay's printed contact rating.
• Do not exceed the relay's rated voltage or current.
• Use an external contactor or suitably rated power relay for larger loads.
• Use appropriate protection for inductive loads such as motors, solenoids, and contactors.

Mains Voltage Warning

The ESP32 operates at low voltage, but the relay contacts may be used with potentially lethal mains voltage.

When switching mains electricity:

• Use a suitable insulated enclosure.
• Maintain adequate separation between low-voltage and mains wiring.
• Do not touch the board while mains power is connected.
• Use appropriate fuses and electrical protection.
• Installation should be performed by a qualified person familiar with mains electrical safety.

Important Notes

• Recommended published input range: 7-60V DC based on the detailed technical specification.
• Do not reverse the DC input polarity.
• Relay switching current must be verified before connecting a load.
• ESP32 GPIO uses 3.3V logic.
• Wireless functions require suitable user-developed firmware.
• Arduino IDE requires the appropriate ESP32 board support package.
• External sensors and accessories must be electrically compatible with the ESP32.

Package Includes

• 1 × ESP32-WROOM-32E Dual Relay Development Board
• 2 × Double-Row Pin Headers
• 1 × Single-Row Pin Header
• 1 × Single-Line Connector Cap / Housing

Power supply, USB/UART programmer, cables, sensors, enclosure, and other accessories are not included.