eBay

Short Description
A professional-grade 8-channel electromagnetic relay board, built around the XL9535 I2C expander chip. Designed for high reliability, clean layout, and ease of integration with external microcontrollers like Arduino and ESP32. Perfect for industrial and home automation applications.

Key Features

8 I2C-Controlled Channels using XL9535 GPIO expander
Compatible with external MCUs (Arduino, ESP32, Raspberry Pi)
Dual Power Support:
• 3.3V for logic (IC side)
• 5V for relays
Compact Size: PCB board dimension 72mm x 150mm
Vertical USB-C Port for DIN rail enclosures
Clearly Marked I2C Address Jumpers (DIP switch)

Package Includes

1x EMR 8-Channel Relay Board
Shipped in sturdy protective cardboard box (190mm x 100mm x 30mm)

Use Cases & Compatibility

Home Automation (Home Assistant / ESPHome)
Industrial Automation
IoT Projects
AC/DC Load Switching

Compatible with:

Arduino (5V logic)
ESP32 (3.3V logic)
Raspberry Pi
Any microcontroller with I2C interface

Technical Specifications

Relay Type: Electromagnetic SPDT (Single Pole Double Throw)
Contact Ratings:

10A @ 250V AC
10A @ 125V AC
10A @ 30V DC
10A @ 28V DC

Coil Specs:

Rated Coil Voltage: 5V DC
Coil Resistance: ~70Ω (±10%)
Trigger Current: ~70mA
Operate Time: ≤10ms
Release Time: ≤5ms

Electrical Life: 100,000 operations
Mechanical Life: 10 million operations
Operating Temperature: -40°C to +85°C
Dielectric Strength: High isolation between control and load sides

Power Configuration Guide

For 5V Logic MCU (e.g., Arduino UNO):
Use a single 5V power source for both the XL9535 IC and the relays.

For 3.3V Logic MCU (e.g., ESP32, Raspberry Pi):
Use Dual Power Mode:

3.3V to power the XL9535 IC
5V to power the relays

Dual Power Mode improves system stability by isolating relay power from MCU power, reducing noise and ensuring reliable I2C communication.

Why Choose This Module?

Professionally designed and manually soldered for maximum reliability
Built for seamless integration into smart systems
Designed with installation & long-term maintenance in mind
Ready for DIN rail enclosure builds
Dual Power Mode improves system stability

Tech Spec from the manufacturer

Power Supply
In Singel Power Mode:  Input a 5V@1A power from VIN&GND1 or 5V&GND2 or Type-C USB5V
In Dual Power Mode:     Input a 3.3-5V@0.5A power from VIN&GND1 and a 5V@1A power from 5V&GND2 or Type-C USB5V

Relay Output
The relay outputs are equivalent to 8 independent SPDT switches,as below:
NC1-NC8: Normally close,the NC disconnect with COM when relay closed and connect with COM when relay released.
COM1-COM8: Common end
NO1-NO8: Normally open end,the NO disconnect with COM when relay released and connect with COM when relay closed.
Control Voltage: DC30V or AC250V Max /channel
Output Current:  0-7A/channel
Output Power:   0-800W/channel

Board dimension :150x72x19mm 141Gr
Box dimension: 190x100x27mm 175gr

Source Code for Arduino , Raspberry PI :

https://github.com/iotmug/8-Channel-Dual-EMR-I2C-TypeC