ESP32-S3-Relay-1CH User Guide

Introduction

ESP32-S3-Relay-1CH is an industrial-grade 1-channel WiFi network relay based on ESP32-S3 main controller and supports WiFi, Bluetooth, RS485, and other peripheral interfaces. It has built-in protection circuits such as power supply isolation and optodecoupler isolation, which is safe, stable and reliable, and suitable for the AIoT field.

Features

Based on ESP32-S3 microcontroller with Xtensa 32-bit LX7 dual-core processor with frequency up to 240MHz
Integrated 2.4GHz WiFi and Bluetooth 5 (LE) dual-mode wireless communication, with superior RF performance
High quality relay, contact rating: ≤10A 250V AC or ≤10A 30V DC
Onboard isolated RS485 interface, for connecting to various RS485 Modbus industrial modules or sensors
Onboard RTC clock chip, supports timing tasks
Onboard USB Type-C port for power supply, firmware downloading and debugging, making development more convenient
Onboard power supply screw terminal, supports 5V power supply only
Onboard optocoupler isolation to prevent interference with control chip from external high-voltage circuit connected to the relay
Onboard digital isolation to avoid external signal interference with the control chip
Onboard integrated power isolation, providing stable isolation voltage, no extra power supply required for the isolated terminal
Onboard RS485 TX/RX indicators for monitoring the operating status of the module
Rail-mounted protective enclosure, easy to install, safe to use

Interfaces

Schematic Diagram of Device Wiring

Dimensions

Electrical Safety Precautions

This product should be operated and used by professional electricians or technical personnel. During use, please ensure electrical safety and take protective measures such as anti-leakage and insulation.
Before installing, maintaining, or replacing relay device, make sure to turn off the power and unplug the device.
Do not attempt to dismantle relay device to avoid damaging the device or risking electric shock.
Please properly install and place the relay device. Avoid using it in damp, overly hot, or flammable environments to prevent safety accidents due to improper installation or use.

Usage Guide

ESP32-S3-Relay-1CH currently provides Arduino-IDF development tool and framework, and you can choose the right development tool according to your project needs and personal habits.

Development Tool


	Arduino IDE Arduino IDE is an open source electronic prototyping platform, convenient and flexible, easy to get started. After a simple learning, you can start to develop quickly. At the same time, Arduino has a large global user community, providing an abundance of open source code, project examples and tutorials, as well as rich library resources, encapsulating complex functions, allowing developers to quickly implement various functions.

Arduino IDE

Arduino IDE is an open source electronic prototyping platform, convenient and flexible, easy to get started. After a simple learning, you can start to develop quickly. At the same time, Arduino has a large global user community, providing an abundance of open source code, project examples and tutorials, as well as rich library resources, encapsulating complex functions, allowing developers to quickly implement various functions.

Components Preparation

ESP32-S3-Relay-1CH x1
USB cable (Type-A male to Type-C male) x1
Modbus RTU Relay x 1
USB TO RS232/485 x 1

Before operating, it is recommended to browse the table of contents to quickly understand the document structure. For smooth operation, please read the FAQ carefully to understand possible problems in advance. All resources in the document are provided with hyperlinks for easy download.

Working with Arduino

This chapter introduces setting up the Arduino environment, including the Arduino IDE, management of ESP32 boards, installation of related libraries, program compilation and downloading, as well as testing demos. It aims to help users master the development board and facilitate secondary development.

Environment Setup

Download and Install Arduino IDE

Click to visit the Arduino official website, select the corresponding system and system bit to download
Run the installer and install all by default

Install ESP32 Development Board

Regarding ESP32-related motherboards used with the Arduino IDE, the 'esp32 by Espressif Systems library must be installed first.
According to Board installation requirement, it is generally recommended to use Install Online. If online installation fails, use Install Offline
For the installation tutorial, please refer to Arduino board manager tutorial

ESP32-S3-Relay-1CH required development board installation instructions
Board name	Board installation requirement	Version number requirement
esp32 by Espressif Systems	"Install Offline" / "Install Online"	3.0.x

Install Library

When installing Arduino libraries, there are usually two ways to choose from: Install online and Install offline. If the library installation requires offline installation, you must use the provided library file
For most libraries, users can easily search and install them through the online library manager of the Arduino software. However, some open-source libraries or custom libraries are not synchronized to the Arduino Library Manager, so they cannot be acquired through online searches. In this case, users can only manually install these libraries offline.
For library installation tutorial, please refer to Arduino library manager tutorial
ESP32-S3-Relay-1CH library file is stored in the demo, click here to jump: ESP32-S3-Relay-1CH Demo

ESP32-S3-Relay-1CH library file installation instructions
Library Name	Description	Version	Library Installation Requirement
ArduinoJson	Lightweight JSON library	v6.21.4	"Install Online" or "Install Offline"
PubSubClient	MQTT message subscription publishing library	v2.8.0	"Install Online" or "Install Offline"
NTPClient	Network time synchronization client library	v3.2.1	"Install Online" or "Install Offline"

Run the First Arduino Demo

If you are just getting started with ESP32 and Arduino, and you don't know how to create, compile, flash, and run Arduino ESP32 programs, then please expand and take a look. Hope it can help you!

New Project

Run the Arduino IDE and select File -> New Sketch
Enter the code:

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
}

void loop() {
  // put your main code here, to run repeatedly:
  Serial.println("Hello, World!");
  delay(2000);
}

Save the project and select File -> Save As.... In the pop-up menu, select the path to save the project, and enter a project name, such as Hello_World, click Save

Compile and Flash Demos

Select the corresponding development board, take the ESP32S3 motherboard as an example:

①. Click to select the dropdown menu option Select Other Board and Port;
②. Search for the required development board model esp32s3 dev module and select;
③. Select COM Port;
④. Save the selection.

If the ESP32S3 mainboard only has a USB port, you need to enable USB CDC, as shown in the following diagram:

Compile and upload the program:

①. Compile the program; ②. Compile and download the program; ③. Download successful.

Open the Serial Monitor window, and the demo will print "Hello World!" every 2 seconds, and the operation is as follows:

Demo

ESP32-S3-Relay-1CH demos
Demo	Basic Description	Dependency Library
01_MAIN_WIFI_AP	RS485 interface control, Bluetooth control, Bluetooth send IP, Web page control (short distance)	Can be flashed directly Web pages are only available if they are connected to device WIFI
02_MAIN_WIFI_STA	RS485 interface control, Bluetooth control, Bluetooth send IP, Web page control (short distance)	Need to modify the WIFI to be connected Web pages can only be used within the intranet
03_MAIN_WIFI_MQTT	RS485 interface control, Bluetooth control, Bluetooth transmit IP, Waveshare cloud control (long distance)	Need to modify the WIFI to be connected The device must be created in the Waveshare cloud
04_MAIN_ALL	RS485 interface control, Bluetooth control, Bluetooth send IP, Web page control (short distance), Waveshare cloud control (long distance)	Need to modify the WIFI to be connected The device must be created in the Waveshare cloud Web pages can only be used within the intranet

Arduino Project Parameter Setting

01_MAIN_WIFI_AP

Demo description

This demo implements the control of 1 relay switch through WiFi, Bluetooth, and RS485. The AP mode of WiFi is enabled in this demo

Precautions

Can be flashed directly
Web pages are only available if they are connected to device WIFI

RS485 Control

Jump to RS485 Control Tutorial

Bluetooth Control

Jump to Bluetooth Control Tutorial

Web Page Control

Jump to Web Control Tutorial, this demo is in AP mode

02_MAIN_WIFI_STA

Demo description

This example implements the control of six relay switches through WiFi, Bluetooth, and RS485. The STA mode of WiFi is enabled in this example

Precautions

Need to modify the WIFI to be connected
The Web page only supports controlling the device and this product to be used under the same network, if you use the mobile phone control, you need to turn off the mobile network

RS485 Control

Jump to RS485 Control Tutorial

Bluetooth Control

Jump to Bluetooth Control Tutorial

Web Page Control

Jump to Web Control Tutorial, this demo is in STA mode

03_MAIN_WIFI_MQTT

Demo description

This example controls 6 relays through MQTT, Bluetooth, and RS485 communication methods. It uses ESP32 as the main control unit, supports Wi-Fi and Bluetooth connections, and provides remote control based on the MQTT protocol

Precautions

Need to modify the WIFI to be connected
Must create the device in Waveshare Cloud

RS485 Control

Jump to RS485 Control Tutorial

Bluetooth Control

Jump to Bluetooth Control Tutorial

Waveshare Cloud Control

Jump to Waveshare Cloud Control

04_MAIN_ALL

Demo description

This example is a collection of RS485 interface control, Bluetooth control, Web page control (near distance), and Waveshare cloud control (long distance).

Precautions

Need to modify the WIFI to be connected
The Web page only supports controlling the device and this product to be used under the same network, if you use the mobile phone control, you need to turn off the mobile network
Must create the device in Waveshare Cloud

RS485 Control

Jump to RS485 Control Tutorial

Bluetooth Control

Jump to Bluetooth Control Tutorial

Web Page Control

Jump to Web Control Tutorial, this demo is in AP mode

Waveshare Cloud Control

Jump to Waveshare Cloud Control

External Expansions

RS485 Extended Relay Channels

Use Modbus RTU Relay to extend 8-ch relay
The 4 main example files are compatible with this operation, and the Extension_Enable in WS_imformification. h needs to be set to 1 (default is 1)
Externally extended relays can be controlled via Bluetooth

Operation Command	Command Function
06 01	Switch the CH1 relay status of Modbus RTU Relay
06 02	Switch the CH2 relay status of Modbus RTU Relay
06 03	Switch the CH3 relay status of Modbus RTU Relay
06 04	Switch the CH4 relay status of Modbus RTU Relay
06 05	Switch the CH5 relay status of Modbus RTU Relay
06 06	Switch the CH6 relay status of Modbus RTU Relay
06 07	Switch the CH7 relay status of Modbus RTU Relay
06 08	Switch the CH8 relay status of Modbus RTU Relay
06 09	Turn on all relays of Modbus RTU Relay
06 0A	Turn off all relays of Modbus RTU Relay

The commands for Bluetooth control relay are characters 1-8, which are hexadecimal 0x06 0x01 ~ 0x38 0x0A
Click the SEND button and fill in the data to be sent (currently hexadecimal sending), enter 0x06 0x01 as below

Send 0x06 0x01 to control relay CH1 for status reversal

Send 0x06 0x0A to control to turn off all relays

Flash Firmware Flashing and Erasing

The current demo provides test firmware, which can be used to test whether the onboard device functions properly by directly flashing the test firmware

bin file path:

..\ESP32-S3-Relay-1CH\Firmware\Factory bin

Flash firmware flashing and erasing for reference

Working with Homeassistant

The product can be controlled online through the Homeassistant built on the Raspberry Pi, and the relevant operations can be found in Reference link

Resources

Demo

ESP32-S3-Relay-1CH Demo

Datasheets

ESP32-S3

Software Tools

Arduino

VScode

VScode official website

Thonny

Thonny official download link

Debugging Tools

FAQ

Question: After the module downloads the demo and re-downloads it, why sometimes it can't connect to the serial port or the flashing fails?

Answer:

Long press the BOOT button, press RESET at the same time, then release RESET, then release the BOOT button, at this time the module can enter the download mode, which can solve most of the problems that can not be downloaded.

Question: Why does the module keep resetting and flicker when viewed the recognition status from the device manager?

Answer:

It may be due to Flash blank and the USB port is not stable, you can long-press the BOOT button, press RESET at the same time, and then release RESET, and then release the BOOT button, at this time the module can enter the download mode to flash the firmware (demo) to solve the situation.

Question: How to deal with the first compilation of the program being extremely slow?

Answer:

It's normal for the first compilation to be slow, just be patient

Question: How to handle the display "waiting for download..." on the serial port after successfully ESP-IDF flashing?

Answer:

If there is a reset button on the development board, press the reset button; if there is no reset button, please power it on again

Question: What should I do if I can't find the AppData folder?

Answer:

Some AppData folders are hidden by default and can be set to show.
English system: Explorer->View->Check "Hidden items"
Chinese system: File Explorer -> View -> Display -> Check "Hidden Items"

Question: How do I check the COM port I use?

Answer:

Windows system:

①View through Device Manager: Press the Windows + R keys to open the "Run" dialog box; input devmgmt.msc and press Enter to open the Device Manager; expand the "Ports (COM and LPT)" section, where all COM ports and their current statuses will be listed.
②Use the command prompt to view: Open the Command Prompt (CMD), enter the "mode" command, which will display status information for all COM ports.
③Check hardware connections: If you have already connected external devices to the COM port, the device usually occupies a port number, which can be determined by checking the connected hardware.

Linux system:

①Use the dmesg command to view: Open the terminal.
①Use the ls command to view: Enter ls /dev/ttyS* or ls /dev/ttyUSB* to list all serial port devices.
③Use the setserial command to view: Enter setserial -g /dev/ttyS* to view the configuration information of all serial port devices.

Question: Why does the program flashing fail when using a MAC device?

Answer:

Install MAC Driver and flash again.

Question: Why is there no output after successfully flashing the code with no issues?

Answer:

Check the schematic diagram for different development boards with Type-C interfaces, and handle the output accordingly:
- For development boards with direct USB output, printf function is supported for printing output. If you want to support output via the Serial function, you will need to enable the USB CDC On Boot feature or declare HWCDC.
- For development boards with UART to USB conversion, both printf and Serial functions are supported for printing output, and there is no need to enable USB CDC On Boot.