The easiest LD2410 to put on a bench: five pins at breadboard spacing, a Bluetooth radio for phone tuning, and the same serial protocol ESPHome already speaks.
The LD2410C is the LD2410 most people end up building with, and the reason is a row of five pins spaced 2.54mm apart. That is breadboard pitch, Dupont pitch, perfboard pitch. The original LD2410 and the LD2410B use a much finer header that needs an adapter cable or a steady soldering hand, so the C removes the first chore on the bench.
Inside, it behaves like the B. It runs the same 24GHz FMCW radar, speaks the same serial protocol at 256000 baud, and carries Bluetooth, so the HLKRadarTool phone app can connect and tune it with nothing else wired. Code written for the B generally runs on the C unchanged, including the ESPHome ld2410 component.
The five pins carry everything you need:
The C is rated to 5m with 0.75m distance gates, and some packs quote 6m. Plan around 5m for someone sitting still. Real reach depends on mounting height, what the radar looks through, and how much the person moves.
| Spec | Value |
|---|---|
| Model | HLK-LD2410C |
| Frequency band | 24GHz ISM (24.125GHz centre) |
| Radar type | FMCW (frequency-modulated continuous wave) |
| Detects | Moving, still, micro-motion, seated and lying people |
| Maximum sensing distance | 5m (some packs quote up to 6m) |
| Distance resolution | 0.75m per gate |
| Detection angle | ±60° |
| Supply voltage | 5V |
| Logic level | 3.3V UART and OUT pin |
| Interfaces | GPIO (OUT pin) and UART |
| Default baud rate | 256000, 8N1 |
| Header | 5 pins at 2.54mm pitch |
| Bluetooth | Yes, for app configuration |
| Configurable | Max distance, per-gate sensitivity, no-one delay |
| Operating temperature | −40 to +85°C |
| Weight | About 0.01kg per module |
| Pack options | 1, 2, 3, 4, 5; 3-pack with 10cm cables; single with CH340 adapter |
The quickest useful build is an ESP32 dev board, four jumpers and ESPHome. You take 5V from the board's VIN or 5V pin, share ground, and cross the serial lines. On a classic ESP32, GPIO16 and GPIO17 make a clean second UART, which keeps the USB port free for logs.
The minimal YAML:
uart:
rx_pin: GPIO16
tx_pin: GPIO17
baud_rate: 256000
parity: NONE
stop_bits: 1
ld2410:
binary_sensor:
- platform: ld2410
has_target:
name: Presence
has_still_target:
name: Still
sensor:
- platform: ld2410
detection_distance:
name: DistanceFlash it, adopt it in Home Assistant and sit still at your desk. Presence should hold while you read and drop after the no-one delay. The longer config, with gate thresholds exposed as number entities, lives on the ESPHome page, and ESP32-C3, D1 Mini and Arduino wiring is on the wiring page.
Two traps catch first builds:
If you only need a light switched, skip the UART entirely. Wire OUT to a GPIO, declare it as a gpio binary sensor, and tune the thresholds over Bluetooth instead.
Bluetooth is the C's second advantage. Install HLKRadarTool, power the module from any 5V USB source, and it shows up in the app with no microcontroller attached. You get live distance, moving and still energy per gate, and a slider for every threshold.
The radar splits its view into gates of 0.75m, gate 0 at the sensor and gate 8 at the far end. Each gate has its own motion and stillness threshold. Tuning means raising thresholds on gates where the room makes energy with nobody in it.
The usual sources of phantom presence:
For how far each gate reaches and how wide the cone is, see range and field of view.
The LD2410C comes as a single module and in 2-, 3-, 4- and 5-packs, plus a 3-pack with jumper cables and a single bundled with a CH340 USB-serial adapter. The modules inside are the same LD2410C; only the count and the extras change. Order for the rooms you plan to cover in the next few months, plus one spare for the bench.
| Pack | Fits | Why |
|---|---|---|
| Single | One room, a first try | Learn the tuning before you commit |
| Single + CH340 | Laptop tuning and firmware | The adapter runs the PC configurator |
| 2-pack | Bedroom plus office | One to mount, one to experiment on |
| 3-pack, with or without cables | A few rooms | Cables save hunting for jumpers |
| 4- and 5-pack | A whole floor | Plan a controller and case per module |
How the C sits among its siblings:
Stay with the C when the space is at least a thumb wide and you value pins you can push a jumper onto. Move to the B when the radar has to hide inside a light switch or a slim profile, and to the S when a wall socket is out of reach.
The side-by-side detail is on LD2410B vs LD2410C. Before you choose, confirm the board carries the 5-pin 2.54mm header and reads LD2410C. Some multi-model bundles mix the C with other radars, so make sure the C is the one you pick. Then plan a case: the radar sees through thin plastic, not through metal.
Yes in behaviour: same 24GHz radar, same 256000-baud protocol and Bluetooth. The C changes the board shape and uses a 2.54mm header instead of fine-pitch pads.
Feed VCC with 5V. The UART and OUT pin run at 3.3V logic, so they connect directly to an ESP32 without level shifting.
Yes. The built-in ld2410 component works with the C at 256000 baud and exposes presence, distances, gate thresholds and a Bluetooth switch.
It is rated to 5m with 0.75m gates, and some packs quote 6m. Mounting height, enclosure material and how still the person is all change the real figure.
No. The OUT pin goes high when someone is present, so it can drive a transistor or relay module directly, and the app handles tuning over Bluetooth.
Best LD2410