A lightweight, platform-agnostic C library for interfacing with the HLK-LD2420 24GHz radar motion detection module. Designed for embedded systems with support for Raspberry Pi Pico and other microcontrollers.
Development Status: This project is under active development. The core API is evolving, and breaking changes may occur. Platform-specific implementations will stabilize as the core APIs mature.
- Pure C99, zero dependencies
- Streaming parser for byte-by-byte processing
- One-shot parser for complete frames
- Little-endian byte order handling
- No dynamic allocation
- Comprehensive error handling
- Platform-agnostic core design
The LD2420 variant supports:
- Detection Range: 0.2m to 8m
- Range Gates: 15 gates at 0.7m increments
- Recommended Max Gate: 10 (for optimal accuracy and reduced noise)
- Interface: UART at 115200 baud
- Operating Frequency: 24GHz FMCW
| Resource Name | Resource URL |
|---|---|
| Sensor Description | https://www.hlktech.net/index.php?id=1291 |
| Sensor Documentation, Tooling, and Protocol Description | https://drive.google.com/drive/folders/1IggDH6ejNSOs8EklQbAXcqUI7KENSZLt |
| Platform | Status | Notes |
|---|---|---|
| Native (Host) | Supported | Core parsing library |
| Raspberry Pi Pico | In Progress | UART layer under development |
- CMake 3.13 or later
- C compiler (GCC, Clang, or MSVC)
- Platform-specific toolchains (see platform READMEs)
git clone https://github.com/mikayelgr/hlkld2420.git
cd hlkld2420Each component has detailed build instructions:
| Component | Documentation |
|---|---|
| Core Library | core/README.md |
| Pico Platform | platform/pico/README.md |
| Examples | examples/README.md |
Streaming Parser (for UART/serial):
#include <ld2420/ld2420_stream.h>
ld2420_stream_feed(&stream, &byte, 1, on_frame_callback);One-Shot Parser (for complete frames):
#include <ld2420/ld2420.h>
ld2420_parse_rx_buffer(buffer, size, &frame_size, &cmd_echo, &status);API documentation is in the header files:
- Core:
ld2420.h,ld2420_stream.h - Pico:
ld2420_pico.h
Packet size limits defined by the protocol:
- Min RX: 14 bytes (simple acknowledgments)
- Max RX: 154 bytes (full configuration read)
- Min TX: 12 bytes (parameter-less commands)
- Max TX: 222 bytes (full configuration write)
See ARCHITECTURE.md for detailed protocol specifications.
add_subdirectory(/path/to/hlkld2420/platform/pico ld2420_pico)
add_executable(my_project main.c)
target_link_libraries(my_project PRIVATE ld2420_pico)include(FetchContent)
FetchContent_Declare(ld2420_pico
GIT_REPOSITORY https://github.com/mikayelgr/hlkld2420.git
GIT_TAG main
SOURCE_SUBDIR platform/pico
)
FetchContent_MakeAvailable(ld2420_pico)
target_link_libraries(my_project PRIVATE ld2420_pico)See examples/ for complete usage demonstrations.
This project is licensed under the MIT License. See the LICENSE file for details.
Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.
For questions or support, please contact mikayelgr.