An implementation for a remote server for HLK-LD2450 human detection radar, and a client.

The remote sensor server is implemented in MicroPython for ESP32, and the client is implemented in Python for Linux/Windows.

The server-client system is designed to be used in a home automation or a home security system (these radars are very good for detecting human presence).

The hlkld2540_network_client Package

The client package is a Python package that provides a client wrapper for the HLK-LD2450 radar sensor server, including high-level functions such as data recording and analysis.

Parsing the data from the server is based on the HLK-LD2450 project..

The _hlkld2450_esp32_upython_server_fs Subdirectory

This is not a python package but rather, a MicroPython project for the ESP32. It is meant to be copied/programmed into an ESP32 board running a MicroPython firmware (with minor adjustments like the WiFi SSID and password).

On-board parsing of the data (optional, not used in the server-client system) is based on the HLK-LD2450 project., with adaptations for MicroPython.

Hardware

• HLK-LD2450 radar sensor
• ESP32 board or module, for example, ESP32 DevKitC + a power source (e.g. USB charger)
• An 04SR cable to connect the radar sensor to the ESP32 board, or some other makeshift cable

Hardware Installation

Under construction.

Software Installation

Under construction.

Firmware Installation

Firmware installation involves 3 steps:

1. Flashing the MicroPython firmware to the ESP32 board
2. Editing the server_hostname_cfg.py and wifi_logins.py files for your network
3. Copying the server files to the ESP32 board

Flashing the MicroPython Firmware

Downloading the Firmware

Micropython is a binary firmware image that operates a Python interpreter and a file system on the ESP32 module. The firmware can be downloaded from the MicroPython website. Be sure to select the version suitable for your ESP32 board. If you're not 100% sure, just try them out - the wrong firmware shouldn't damage the board.

Using Esptool

Typically, the firmware is flashed to the ESP32 board using the esptool.py script.

1. Connect the ESP32 board to your computer using a USB cable and find the port it's connected to (in Windows: open Device Manager, look under Ports (COM & LPT)).
2. Open a terminal with Python installed and run the following command: pip install esptool As a sanity check, run: esptool.py -p COMX chip_id (replace COMX with the port number).
3. After installation, run:
   esptool.py --chip esp32 --port COMX erase_flash
   to erase the flash memory (replace COMX with the port number). If you're using a fancy ESP32-S3 module, use esp32s3 instead of esp32.
4. Finally, run:
   esptool.py --chip esp32 --port COMX --baud 460800 write_flash -z 0x1000 <path_to_firmware>
   to flash the firmware (replace COMX with the port number and <path_to_firmware> with the path to the firmware binary).
   Example:
   esptool.py --chip esp32 --port com4 --baud 460800 write_flash -z 0x1000 esp32-20230426-v1.20.0.bin
   If you're using a fancy ESP32-S3 module, use esp32s3 instead of esp32, and 0 instead of 0x1000.

You're done! The ESP32 board should now be running MicroPython and responsive to serial commands, and can be connected to via a serial terminal (e.g. PuTTY) or a MicroPython-compatible IDE (e.g. Thonny).

Editing the server_hostname_cfg.py and wifi_logins.py Files

The server_hostname_cfg.py file holds the hostname alias the remote sensor server will be using - it should be unique to each server (if you'll be using more than one server in your network).
The wifi_logins.py file holds the SSID and password of the WiFi network the server will be connecting to - it should be edited so that your ESP32 board can connect to your network.
Edit both files before copying them to the ESP32 board.

Copying the Server Files to the ESP32 Board

The server files should be copied to the ESP32 board using a tool like mpypack.

1. Install mpypack by running:
   pip install mpypack
2. Navigate to the folder containing the server files (cd _hlkld2450_esp32_upython_server_fs) and run:
   mpypack -p COMX sync (replace COMX with the port number)

Installing the HLK-LD2450 Project

Unfortunately, the project isn't structured as a python package - so it needs to be installed manually by cloning the repository and copying serial_protocol.py into a serial_protocol subdirectory in venv/Lib/site-packages.
The serial_protocol.py file should also be edited to remove the pyserial import dependency (it's not needed in this project).