HLK-LD2420 24GHz Human Presence Radar Sensor Module

The Hi-Link HLK-LD2420 is a compact 24GHz FMCW mmWave human presence radar sensor designed to detect moving and micro-motion human targets. It operates from 3.3V, supports UART and GPIO status output, offers configurable detection zones and sensitivity, and can detect moving targets at distances up to 8m in wall-mounted applications.

Description

The HLK-LD2420 24GHz Human Presence Radar Sensor Module is designed for smart-home, lighting, security, occupancy sensing, automation, and AIoT applications where reliable human-presence detection is required.

Unlike a basic PIR motion sensor, the HLK-LD2420 uses 24GHz FMCW millimeter-wave radar technology together with onboard signal processing to detect human movement and micro-motion within a configurable sensing area. The module can continuously report detection results and allows parameters such as detection distance, zone sensitivity, and reporting behavior to be adjusted through Hi-Link's configuration software.

For wall-mounted operation, the manufacturer specifies a maximum moving-person detection distance of approximately 8m and micro-motion detection up to approximately 6m. The sensing angle can reach approximately ±60°, depending on mounting, environment, target movement, and configuration.

The actual Chip.pk stock is marked HLK-LD2420 V2.1. It uses a compact 20 × 20mm PCB and provides a 5-pin power/communication interface for integration with microcontrollers, controllers, and embedded systems.

Key Features

• Hi-Link HLK-LD2420
• Actual stock PCB revision: V2.1
• 24GHz FMCW mmWave radar
• Human presence, movement, and micro-motion detection
• Moving-person detection up to approximately 8m with wall mounting
• Micro-motion detection up to approximately 6m with wall mounting
• Detection coverage up to approximately ±60°
• Near-range sensing down to approximately 0.2m
• Configurable sensing distance and zone sensitivity
• UART communication interface
• Dedicated presence-status GPIO output
• Real-time detection reporting
• Approx. 10Hz data refresh rate
• Nominal 3.3V operation
• Compact 20 × 20mm module size
• Suitable for smart lighting, occupancy detection, automation, and security applications

Technical Specifications

Manufacturer specifications for sensing distance, angle, accuracy, current, refresh rate, voltage, and dimensions are documented in the current HLK-LD2420 user manual. r0.hlktech.com

Interface / Pinout

The official Hi-Link manual defines the main 5-pin J2 connector as:

The OT2 output goes high when human presence is detected and low when no presence is detected. The official interface operates at 3.3V logic levels. Hailinke Support Center

Stock marking note: the supplied V2.1 PCB imagery labels the signal pins as IO1 / RX / IO2, while the current Hi-Link manual refers to the corresponding functional pins as OT1 / RX / OT2. Chip.pk should describe the functions according to the official manual rather than guessing from the abbreviated PCB labels.

Applications / Use Cases

• Human presence detection
• Smart lighting control
• Room occupancy sensing
• Smart home automation
• Energy-saving systems
• Automatic display wake/sleep systems
• Building automation
• Security and access systems
• Smart switches
• AIoT occupancy sensing
• Indoor monitoring
• Appliance presence control
• Micro-motion detection
• Embedded radar sensing projects

Compatibility

The HLK-LD2420 can be integrated with microcontrollers and embedded control systems through its 3.3V UART interface and GPIO presence-status output.

It may be used with platforms such as ESP32, STM32, Arduino-compatible controllers, PLC-interface circuitry, or custom embedded boards, provided their electrical interface is compatible.

The module itself uses 3.3V logic. Do not assume direct compatibility with a 5V UART or GPIO system without checking the controller's electrical specifications or using suitable level conversion.

For configuration through a computer, Hi-Link documents use of a USB-to-TTL serial adapter and a UART baud rate of 115200 with its configuration utility.

Detection performance can vary with mounting position, room layout, moving objects, reflective materials, sensitivity settings, and environmental conditions. Manufacturer maximum-range values should therefore be treated as application-dependent rather than guaranteed in every installation.

Package Contents

• 1 × HLK-LD2420 24GHz Human Presence Radar Sensor Module

Buy in Pakistan

Buy the HLK-LD2420 24GHz human presence sensor in Pakistan from Chip.pk for smart lighting, occupancy sensing, automation, security, and AIoT projects.With 24GHz FMCW radar, up to 8m moving-person detection, micro-motion sensing, UART configuration, GPIO presence output, and adjustable detection parameters, the LD2420 provides a compact alternative to conventional motion-only sensing solutions.

FAQs

1. What is the HLK-LD2420 sensor?
The HLK-LD2420 is a 24GHz FMCW mmWave human presence radar sensor designed to detect human movement and micro-motion for occupancy, automation, smart lighting, and monitoring applications.

2. What is the maximum detection range of the LD2420?
For wall-mounted applications, Hi-Link specifies moving-person detection up to approximately 8m and micro-motion detection up to approximately 6m. Actual range depends on mounting, environment, sensitivity settings, and target movement.

3. Can the LD2420 detect a stationary person?
The module is designed to detect human presence including micro-motion, allowing it to detect much smaller movements than a conventional motion-only PIR sensor. Completely motionless detection performance depends on installation and configuration.

4. What frequency does the HLK-LD2420 use?
It operates in the 24.0–24.25GHz millimeter-wave radar band.

5. What voltage does the LD2420 require?
The module operates from approximately 3.0V to 3.6V, with 3.3V as the typical supply voltage.

6. Does the LD2420 support UART communication?
Yes. It provides a 3.3V UART interface that can be used for configuration and data communication.

7. Does the module provide a simple presence output?
Yes. A dedicated digital presence-status output is provided. The output changes state according to whether human presence is detected.

8. Can I use the LD2420 with ESP32?
Yes. It can be interfaced with an ESP32 using its 3.3V UART and GPIO signals, provided the wiring and firmware are configured correctly.

9. Can I use the LD2420 with Arduino?
Yes, but the LD2420 uses 3.3V logic. If the selected Arduino board uses 5V UART or GPIO levels, suitable level shifting may be required.

10. Is the LD2420 the same as a PIR motion sensor?
No. PIR sensors detect changes in infrared radiation, while the LD2420 uses 24GHz FMCW radar and can detect movement and micro-motion.

11. Can the detection distance and sensitivity be adjusted?
Yes. Hi-Link provides configuration options for detection zones, sensitivity, and reporting parameters through the module's serial interface and configuration software.

12. What is the PCB version of the Chip.pk stock?
The supplied Chip.pk stock shown in the product images is marked HLK-LD2420 V2.1.