ESP32-S3 1-Channel WiFi Relay Module with RS485 – Onboard Antenna

The Waveshare ESP32-S3 1-Channel WiFi Relay Module is an industrial-grade wireless relay controller designed for smart home automation, industrial control, remote switching and Internet of Things (IoT) applications. Powered by the ESP32-S3 dual-core microcontroller, it supports 2.4GHz WiFi, Bluetooth 5 Low Energy (BLE) and isolated RS485 communication, providing flexible control and reliable connectivity.

Featuring a 10A relay rated for up to 250V AC or 30V DC, the module allows users to control electrical devices, lighting, machinery and other connected equipment through wireless or RS485-based control systems.

This version features an integrated onboard ceramic antenna, eliminating the need for an external antenna. It also includes multiple electrical isolation and protection circuits, a real-time clock (RTC) and a protective DIN rail-mount enclosure for convenient installation.

Key Features

• ESP32-S3 Microcontroller: Equipped with a 32-bit Xtensa LX7 dual-core processor running at up to 240MHz.

• WiFi Connectivity: Integrated 2.4GHz WiFi (802.11 b/g/n) for wireless monitoring and remote relay control.

• Bluetooth 5 LE: Supports Bluetooth Low Energy communication for compatible wireless applications.

• 1-Channel Relay: High-quality normally open (NO) relay with a contact rating of up to 10A at 250V AC or 30V DC.

• Onboard Antenna: Integrated ceramic antenna for WiFi and Bluetooth connectivity without an external antenna.

• Isolated RS485 Interface: Supports communication with compatible RS485 devices, sensors and Modbus systems.

• Multiple Protection Circuits: Includes optocoupler isolation, digital isolation, power isolation and surge protection.

• Real-Time Clock (RTC): Onboard PCF85063 RTC chip supports time-based automation and scheduled tasks.

• USB Type-C Interface: Supports power supply, firmware uploading, debugging and USB communication.

• 5V DC Power Supply: Can be powered through the USB-C port or dedicated screw terminals.

• LED Status Indicators: Dedicated indicators for power, relay operation and RS485 communication.

• DIN Rail-Mount Enclosure: Protective housing designed for installation on standard 35mm DIN rails.

• Arduino Development Support: Compatible with Arduino-based development, with manufacturer examples and documentation available.

WiFi and Bluetooth Remote Relay Control

The ESP32-S3 Relay Module integrates 2.4GHz WiFi and Bluetooth 5 Low Energy, allowing developers to create wireless switching and automation systems.

Using custom firmware, the relay can be controlled through compatible WiFi networks, Bluetooth-enabled devices or IoT applications.

The module is suitable for applications such as:

• Remote switching of electrical equipment

• Smart home lighting and appliance automation

• Wireless industrial control systems

• IoT monitoring and automation

• Scheduled switching and timer-based control

The ESP32-S3 also supports lightweight networking protocols such as MQTT and HTTP through suitable firmware, making it possible to integrate the module into compatible IoT platforms and custom monitoring dashboards.

High-Quality 10A Relay Output

The module features a single normally open (NO) relay output designed for switching electrical loads.

Relay Contact Ratings:

• Maximum AC Rating: 10A at 250V AC

• Maximum DC Rating: 10A at 30V DC

• Relay Channels: 1

• Contact Configuration: Normally Open (NO)

• Output Terminals: COM and NO

The relay can be used to switch compatible lighting circuits, electrical appliances, control equipment and other loads within its specified ratings.

The normally open contact remains open when the relay is not energised and closes when activated.

Isolated RS485 Communication

The onboard isolated RS485 interface enables communication with compatible industrial devices, controllers and sensors.

RS485 is widely used in industrial automation due to its suitability for reliable serial communication over longer cable distances.

The module can communicate with compatible Modbus RTU devices when configured with suitable software.

RS485 Features:

• Isolated RS485 communication interface

• A+ and B- screw terminals

• Automatic transmit and receive direction control

• TVS diode protection

• Surge and electrostatic discharge (ESD) protection

• Optional 120Ω termination resistor, enabled using a jumper

• Dedicated transmit and receive LED indicators

These features make the module suitable for industrial monitoring, equipment control and integration with RS485-based automation systems.

Multiple Electrical Isolation and Protection Circuits

The Waveshare ESP32-S3 Relay Module incorporates several protection features designed to improve reliability and reduce electrical interference.

Optocoupler Isolation: Helps isolate relay control circuitry from interference associated with external electrical loads.

Digital Isolation: Reduces interference from external communication signals.

Power Supply Isolation: Provides an isolated power supply for the relevant interface circuitry without requiring an additional external isolated power source.

TVS Surge Protection: Helps suppress transient voltage spikes and electrical disturbances.

These protection features make the module suitable for demanding electronics and industrial control applications.

Real-Time Clock for Scheduled Automation

The onboard PCF85063 RTC chip enables time-based control and scheduled automation.

With suitable firmware, users can configure the relay to switch equipment at specified times or follow programmed operating schedules.

An RTC battery connector is provided for connecting a compatible backup battery, helping maintain timekeeping when the main power supply is disconnected.

USB-C Programming and Power Supply

The module includes a USB Type-C connector for convenient programming, debugging, communication and power.

It also features a dedicated 5V DC screw terminal for integration into control systems.

The ESP32-S3 microcontroller can be programmed using the Arduino development environment, allowing developers to create custom relay control applications, wireless automation systems and communication interfaces.

DIN Rail-Mount Protective Enclosure

The module is supplied in a protective enclosure designed for installation on standard 35mm DIN rails.

This makes it convenient to mount inside electrical control panels, automation cabinets and equipment enclosures.

The compact housing provides convenient access to the power, relay and RS485 terminals while helping protect the internal electronics.

Technical Specifications

• Brand: Waveshare

• Model: ESP32-S3-Relay-1CH

• Microcontroller: ESP32-S3R8

• Processor: Xtensa 32-bit LX7 dual-core

• Maximum Clock Speed: 240MHz

• Flash Memory: 16MB

• WiFi: 2.4GHz IEEE 802.11 b/g/n

• Bluetooth: Bluetooth 5 Low Energy

• Antenna: Integrated onboard ceramic antenna

• Relay Channels: 1

• Relay Contact Type: Normally Open (NO)

• Relay Contact Rating: Up to 10A at 250V AC / 30V DC

• Communication Interface: Isolated RS485

• RS485 Terminals: A+ and B-

• RS485 Termination: Optional 120Ω resistor, jumper enabled

• Input Voltage: 5V DC

• USB Interface: USB Type-C

• Real-Time Clock: PCF85063

• Protection: Optocoupler isolation, digital isolation, power isolation, TVS surge and ESD protection

• Status Indicators: Power, relay, RS485 TX and RX

• Expansion Header: 20-pin, 2.00mm pitch

• Enclosure: DIN rail-mount protective case

• DIN Rail Compatibility: 35mm

• Dimensions: 91.6 × 23.3 × 58.7mm

• Development Support: Arduino

• Antenna Version: Onboard antenna

Applications

The Waveshare ESP32-S3 1-Channel WiFi Relay Module is suitable for a variety of automation and electronic control projects, including:

• Smart home automation systems

• WiFi-controlled lighting and appliances

• Industrial equipment switching

• Remote relay control over WiFi or Bluetooth

• RS485 and Modbus communication projects

• Scheduled electrical equipment control

• IoT-based automation and monitoring

• Electrical control panel installations

• Wireless machine control

• Building automation systems

• Custom MQTT and HTTP relay controllers

• Educational and industrial electronics development

Why Choose the Waveshare ESP32-S3 WiFi Relay Module?

The Waveshare ESP32-S3 1-Channel Relay Module combines powerful microcontroller processing, wireless communication and industrial connectivity in a compact, rail-mounted controller.

With WiFi, Bluetooth 5, isolated RS485 communication, a 10A relay and multiple protection circuits, it provides a flexible platform for developing reliable remote switching and automation solutions.

The integrated onboard antenna simplifies installation, while the USB-C interface, real-time clock and Arduino development support make it suitable for both custom electronics projects and industrial automation applications.

Whether you are building a WiFi relay controller, integrating RS485 sensors or developing an automated switching system, the ESP32-S3 Relay Module offers a practical and versatile solution.

Important: The module requires a regulated 5V DC supply. The relay contact rating does not indicate the module's power supply voltage. Mains voltage wiring must be carried out by a suitably qualified person, with appropriate protection and enclosure requirements.

Manufacturer Part Number: ESP32-S3-Relay-1CH

Documentation and Development Resources: https://www.waveshare.com/wiki/ESP32-S3-Relay-1CH