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.
