LD2410B Test Kit

The module is a standard HLK-LD2410B: 24GHz radar, 5m range, ±60° coverage and Bluetooth. That means you get two ways in from the start:

• Serial: the PC configurator at 256000 baud, with live energy for every distance gate and full control of thresholds.
• Bluetooth: the HLKRadarTool phone app, handy once the module is propped up across the room.

A first session worth doing:

1. Connect the kit, open the tool, pick the COM port and set 256000 baud.
2. Sit in front of the radar and watch the moving and still energy climb in the gate you are in.
3. Walk back one step at a time. Each 0.75m moves you one gate further.
4. Leave the room and note which gates still show energy with nobody there.
5. Raise those gates' thresholds, cap the farthest gate, and save.

Twenty minutes of that teaches you more about the LD2410 than any spec sheet. You see how the still-energy reading follows small movements like breathing, how a fan lights the near gates, and how far the radar reaches through a door.

Per Hi-Link's serial protocol document, the frames are easy to pick out:

• Report frames start with F4 F3 F2 F1 and end with F8 F7 F6 F5.
• Command and reply frames start with FD FC FB FA and end with 04 03 02 01.
• A target-state byte in each report reads 00 for no one, 01 for moving, 02 for still, 03 for both.
• Moving and still distances and energies follow in the same frame.

To change settings from your own code, you wrap commands between an enable-configuration command and an end-configuration command. The same sequence is what ESPHome and the Arduino libraries send under the hood.

Engineering mode is where the test kit earns its keep. Log a few minutes of per-gate energy with the room empty and then occupied, and you have real numbers for your room to set thresholds from, instead of guesses.

Pin functions and power figures are on the LD2410 pinout page, and the protocol basics sit in the datasheet summary.

Moving the module to an ESP32 build:

1. Note your saved thresholds, farthest gates and no-one delay from the tool.
2. Disconnect the kit and wire the module: 5V, GND, module TX to board RX, module RX to board TX.
3. Flash ESPHome with the ld2410 component at 256000 baud.
4. Confirm presence in Home Assistant, then fine-tune thresholds there or over Bluetooth.

uart:
  rx_pin: GPIO16
  tx_pin: GPIO17
  baud_rate: 256000
  parity: NONE
  stop_bits: 1

ld2410:

binary_sensor:
  - platform: ld2410
    has_target:
      name: Presence

The B's pads are fine pitch, so plan how you connect it in the final build:

• Solder thin silicone wires straight to the pads for a slim install.
• Use a fine-pitch header and socket if you want to swap modules.
• Keep the kit's connection for bench work and buy a pinned LD2410B-P for the build.

Full YAML with thresholds and a Bluetooth switch is on the ESPHome page, and per-board UART pins are on the wiring page. For enclosure ideas, see LD2410 cases.

Keep the kit itself. When a mounted sensor misbehaves months later, a spare module on the kit lets you compare readings in the same room and tell a tuning problem from a faulty board.

The two test kit versions are the same kit under slightly different names; either one lands the same parts on your desk. The part that pays off is having one on the bench before the first sensor goes on a wall: a kit makes every later module faster to set up, because you already know which gates your rooms light up and which thresholds hold a still person.

What to buy after the kit, by build:

Skip the kit if:

• You only need one sensor and plan to tune it from a phone. A bare B or C does that.
• You already own a 3.3V USB-serial adapter. Wire it to any B or C and you have the same laptop link.
• You want a finished sensor. The AKAMATIS v2.2 is an LD2410B already built into one.

Take the kit if:

• You are designing a product and need to log raw frames.
• You want to understand the gates before choosing between versions.
• You prefer a big screen to a phone for tuning.

The version comparison, B against C and the rest, is on LD2410B vs LD2410C.