LD2410C 24GHz Human Presence Sensor

This compact LD2410C 24GHz radar module detects whether a person is present and/or moving within an indoor space. Unlike conventional PIR motion sensors that use body heat for detection, the 24GHz LD2410C uses 24GHz radar to detect both obvious movement and the smaller movements made by someone sitting or standing relatively still. The module uses the LD2410-compatible interface and communication protocol and can be used with software such as Nick Reynolds' LD2410 Arduino library and the ESPHome LD2410 component. It provides a simple digital presence output, along with UART data including moving and stationary target states, approximate distance and signal energy. It also supports Bluetooth monitoring and configuration using compatible applications such as HLKRadarTool (Android / iOS). Unlike PIR, radar can also detect through some non-metallic materials and may respond to movement beyond the intended area. Careful positioning and sensitivity adjustment may be needed to prevent detections through thin walls, doors or enclosures. It's ideal for home automation occupancy detection, automatic lighting, display wake-up systems and other projects that need to distinguish between an empty room and a person who is present but not moving much. The module comes with a pre-soldered 2.54mm header and is suitable for use with breadboards and jumper wires. Which presence sensor should I choose? The LD2410C, LD2410B and LD2420 are all 24GHz radar presence sensors capable of detecting normal movement and the smaller movements made by a relatively stationary person. The main differences are their physical format, supply requirements, configuration options and software compatibility. Note: Sensors of this type are often described commercially as “mmWave” sensors. Strictly speaking, 24GHz has a wavelength of approximately 12.5mm, just outside the conventionally defined millimetre-wave range of 10mm to 1mm.

* The LD2410C (this product) is a convenient general-purpose option, with a compact breadboard-friendly layout, Bluetooth configuration and broad support from existing LD2410 Arduino and ESPHome integrations.

* The LD2410B provides similar LD2410 sensing and software compatibility in a longer, narrower format, with both pre-soldered and headerless variants available.

* The LD2420 is a separate 3.3V design with its own serial protocol and threshold-based calibration system, making it better suited to projects that specifically require native 3.3V power or its different detection characteristics.

Presence sensor comparison

LD2410C LD2410B-P LD2420

Supply voltage 5V 5V 3.3V

Signal levels 3.3V compatible 3.3V compatible 3.3V

Configuration Bluetooth or UART Bluetooth or UART UART

Reported target information Separate moving and stationary target data Separate moving and stationary target data Presence, distance and radar energy data

Detection tuning Separate moving and stationary sensitivity for each distance gate Separate moving and stationary sensitivity for each distance gate Per-gate trigger and hold thresholds with calibration support

Typical maximum range Approximately 6m Approximately 6m Up to approximately 8m

Arduino compatibility Established LD2410 libraries Established LD2410 libraries Uses a separate LD2420 protocol and software integration

ESPHome compatibility ESPHome LD2410 component ESPHome LD2410 component Separate ESPHome LD2420 component

Physical format Compact, breadboard-friendly PCB Long, narrow PCB Compact square PCB

Header options Pre-soldered header Pre-soldered or headerless variant Pre-soldered header

Best suited to General prototyping, Bluetooth tuning and established software support Projects needing a narrow PCB or direct integration without headers Native-3.3V projects and threshold-based calibration

Features

* 24GHz FMCW radar presence sensing

* Detects moving and relatively stationary people

* Reports moving and stationary target states separately

* Approximate target distance and signal energy data

* Detection distance configurable up to approximately 6m

* Bluetooth monitoring and configuration

* Separate moving and stationary sensitivity settings for each distance gate

* Adjustable maximum detection distance and absence delay

* Simple active-high digital occupied/unoccupied output

* LD2410-compatible UART interface

* Support from established Arduino and ESPHome integrations

* 5V supply input with 3.3V-compatible UART signals

* Pre-soldered breadboard-compatible 2.54mm header

Specifications

Sensor type 24GHz FMCW radar presence sensor

Detection Moving and relatively stationary people

Maximum detection distance Up to approximately 6m

Supply voltage 5V

Interfaces UART and digital presence output

UART baud rate 256000 baud by default

Logic level 3.3V-compatible UART and digital output

Bluetooth Monitoring and configuration

Pin spacing 2.54mm

Dimensions Approximately 22 × 16mm

Protocol compatibility LD2410-compatible

Resources

* LD2410 Arduino library by Nick Reynolds

* LD2410 Sensor in ESPHome

Pinout

1 TX UART data transmitted by the radar module. Connect to the microcontroller RX pin.

2 RX UART data received by the radar module. Connect to the microcontroller TX pin.

3 OUT Digital presence output. Normally HIGH when presence is detected.

4 GND Ground connection.

5 VCC Power input, typically 5V.

Package Contents

* 1x LD2410C 24GHz Human Presence Sensor (headers pre-soldered)