LILYGO T3-S3 LR1121

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Table of Contents

• Description
• Preview
• Modules
• Quick Start
• Pin Overview
• Related Tests
• FAQ
• Projects
• Resources
• Dependent Libraries

Description

LILYGO T3-S3 LR1121 is a highly integrated IoT development board based on ESP32-S3, supporting dual-band LoRa communication at 2.4GHz and 830-945MHz, covering long-distance transmission requirements (10km+), and compatible with spectrum regulations in different regions worldwide. The onboard 1.3-inch OLED screen displays data in real-time, equipped with a TF card slot for storage expansion, and a Type-C interface simplifies power supply and debugging. It provides abundant GPIO pins (supporting ADC, SPI, I2C, and other protocols), allowing flexible connection of sensors or peripherals. Combined with Wi-Fi/Bluetooth 5.0, it enables multi-protocol interconnection. Suitable for smart agriculture monitoring, industrial equipment management, emergency communication networks, and smart home gateways, it balances low-power design with a compact structure, making it an ideal hardware platform for efficiently building IoT systems.

Preview

Physical Image

Pin Diagram

Modules

MCU

• Chip: ESP32-S3FH4R2
• PSRAM: 2MB (QSPI PSRAM)
• FLASH: 4MB
• Wireless: 2.4GHz Wi-Fi + Bluetooth 5.0

Display

• Size: 1.3-inch OLED display
• Interface: I2C
• Driver: Standard OLED driver

Wireless Communication

• LoRa Chip: LR1121
• Frequency Band: 830-945MHz + 2.4GHz dual-band
• Communication Distance: 10km+ (ideal conditions)

Power Management

• RTC: PCF85063ATL Real-time Clock
• Power Supply: 5V/500mA
• Battery Interface: 1.25mm battery interface

Overview

Quick Start

Example Support

PlatformIO

1. Install Visual Studio Code and Python
2. Search for the PlatformIO extension in Visual Studio Code and install it
3. After installation, restart Visual Studio Code
4. After restarting, select File -> Open Folder in the top left corner -> choose the LilyGo-LoRa-Series directory
5. Wait for third-party dependency libraries to install
6. Click to open the platformio.ini file, under the platformio section
7. Select the development board name you want to use under default_envs and uncomment it
8. Uncomment one line of src_dir = xxxx, ensuring only one line is active. Please note the example comments which explain which features are available and which are not.
9. Click the (✔) symbol at the bottom left to compile
10. Connect the development board to the computer using a USB-C cable (Micro-USB interface is for module firmware upgrade)
11. Click (→) to upload the firmware
12. Click (plug symbol) to monitor serial output
13. If unable to upload or USB device keeps blinking, please check the FAQ below

Arduino

1. Install Arduino IDE
2. Install Arduino ESP32
3. Copy all folders in the lib directory to the Sketchbook location directory. To find the library location, refer here
   • Windows: C:\Users\{username}\Documents\Arduino
   • macOS: /Users/{username}/Documents/Arduino
   • Linux: /home/{username}/Arduino
4. Open the corresponding example
   • Open the downloaded LilyGo-LoRa-Series folder
   • Open the examples folder
   • Select the example file and open the file with the ino extension
5. Select the corresponding development board model in the Arduino IDE Tools menu, click the corresponding option in the list below to select

• Board Revision please select according to the actual model

6. Upload the program

Development Platforms

1. Micropython
2. Arduino IDE
3. Platform IO
4. VS Code

Pin Overview

Communication Performance

FAQ

• Q. How to adjust the external antenna resistor?
  A. Refer to the image below to adjust the resistor direction for the external antenna:

  

• Q. What advantages does LR1121 have over traditional LoRa chips?
  A. LR1121 supports dual-band (Sub-GHz + 2.4GHz), providing greater deployment flexibility and better anti-interference capability.

• Q. Can dual bands work simultaneously?
  A. LR1121 supports band switching but cannot transmit and receive data on different bands simultaneously.

• Q. What factors affect communication distance?
  A. Communication distance is affected by environmental obstacles, antenna gain, transmission power, data rate, and other factors.

• Q. Why does my board fail to upload programs?
  A. Please hold down the "BOOT" button and press the "RST" button simultaneously, then release the "RST" button to enter download mode, and try uploading the program again.

Projects

• T3-S3-LR1121_V1.3

Resources

• LR1121 Datasheet
• ESP32-S3 Datasheet
• PCF85063ATL Datasheet

Dependent Libraries

• u8g2
• XPowersLib
• LoRa
• RadioLib