T-LoRa Dual get it now

Overview

T-LoRa-Dual (T-ELRS) is a dual-band wireless communication module based on the ESP32-PICO-D4 microcontroller, integrating two LR1121 multi-band wireless chips. Specifically designed for the ExpressLRS flight control protocol, it supports Sub-GHz / 1.9 GHz / 2.4 GHz multi-band concurrent communication. Suitable for remote control transmitter modules, drone data links, and IoT long-distance communication scenarios.

The two LR1121 modules share the SPI bus (SCK/MOSI/MISO) with independent CS signals, and the AT2401 RF switch controls antenna switching for dual-channel TX/RX.

Quick Start

Example Support

Example	PlatformIO/Arduino	ESP-IDF	Description
T-ELRS Examples	✓		T-ELRS and ExpressLRS examples
ExpressLRS	✓		ExpressLRS protocol firmware

PlatformIO (ExpressLRS)

1. Open the ExpressLRS/src subdirectory with VS Code
2. Select your device model from the target list
3. Click ✓ to compile and → to upload (first compile downloads dependencies — may be slow)

PlatformIO (T-ELRS)

1. Open the T-ELRS directory with VS Code
2. Open platformio.ini, uncomment the example to compile
3. Click ✓ to compile and → to upload

Arduino (T-ELRS)

1. Copy the lib directory from T-ELRS to your Arduino libraries folder
2. Open the example from the examples directory
3. Select board and default configuration:

Arduino IDE Setting	Value
Board	ESP32 Pico Kit (or compatible)

4. Click Upload

Flashing Firmware

1. Hold the BOOT button, then press and release RESET to enter download mode
2. Use ESP Flash Download Tool (Windows) to flash firmware
3. If flashing fails, try a lower baud rate or a different USB cable
4. Press RESET to restart after flashing

Video

Key Features

• ESP32-PICO-D4 dual-core @ 240 MHz, Wi-Fi + Bluetooth
• Two independent LR1121 modules: Sub-GHz (410–960 MHz) + 1.9 GHz / 2.4 GHz
• AT2401 RF switch for dual-channel TX/RX antenna control
• ExpressLRS protocol support (True Diversity)
• Shared SPI bus with independent CS, RST, BUSY, DIO9 per module
• Status LED (GPIO5)

Product Parameters

Feature	Specification
MCU	ESP32-PICO-D4 @ Dual-core, 240 MHz
Wi-Fi	2.4 GHz
Bluetooth	Bluetooth 4.2
LoRa Module	LR1121 × 2
Frequency Bands	Sub-GHz + 1.9 GHz + 2.4 GHz
RF Switch	AT2401
Protocol Support	LoRa, FSK, ExpressLRS

Pin Diagram

LR1121-1 Module

Signal	ESP32 Pin
MISO	33
MOSI	32
SCK	25
CS	27
DIO9	37
RST	26
BUSY	36

LR1121-2 Module

Signal	ESP32 Pin
MISO	33 (shared)
MOSI	32 (shared)
SCK	25 (shared)
CS	13
DIO9	34
RST	21
BUSY	39

AT2401 RF Switch

Signal	ESP32 Pin	Function
TX1	14	TX channel 1 control
TX2	15	TX channel 2 control
RX1	10	RX channel 1 control
RX2	9	RX channel 2 control

Signal	GPIO	Function
LED	5	Status indicator

Dimension Diagram

Schematic

Datasheet

Software Development

• T-LoRa-Dual / T-ELRS GitHub Repository
• ExpressLRS Documentation

File Directory

├── ExpressLRS/            # ExpressLRS firmware
│   └── src/
│       ├── user_defines   # ExpressLRS configuration
│       ├── hardware/
│       │   ├── RX/        # Receiver hardware IO (T-ELRS LR1121 True Diversity.json)
│       │   ├── TX/        # Transmitter hardware IO
│       │   └── targets.json
│       └── lib/
├── T-ELRS/                # T-ELRS code
│   ├── src/
│   ├── examples/
│   ├── firmware/
│   └── hardware/
└── README.md

FAQ

• Q. How to enter download mode? A. Hold the BOOT button, then press and release RESET. The device will enter download mode.

• Q. ExpressLRS compilation is slow on first run? A. The first build downloads dependencies — this is normal. Subsequent builds are faster.

• Q. Which ExpressLRS target to select? A. For True Diversity RX: BAYCKRC 900/2400 Dual Band Gemini RX in targets.json.

Version History

Version	Release Date	Update Description
T-ELRS V1.0	2025-03-15	Initial version, ExpressLRS protocol support
T-ELRS V1.1	2025-06-20	Optimized SPI timing, improved stability

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