Hi-Link HLK-LD2410B 24GHz mmWave Radar Human Presence Sensor Bluetooth + UART

Specifications

• Model: Hi-Link HLK-LD2410B (Bluetooth Version).

• Frequency: 24 GHz ISM Band.

• Modulation: FMCW (Frequency Modulated Continuous Wave).

• Detection Distance: 0.75m to 6m (Configurable).

• Detection Angle: ±60° Horizontal / ±60° Vertical.

• Interfaces:

  • UART: Serial communication (Baud 256000) for data.

  • GPIO (OUT): High (3.3V) when presence detected, Low (0V) when clear.

  • Bluetooth: BLE 4.2 for App Configuration.

• Operating Voltage: 5V DC (Accepts 5V on VCC).

• Logic Voltage: 3.3V (UART/GPIO).

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• Prerequisite: You should be comfortable with basic wiring (VCC/GND/OUT).

• The Upgrade: This replaces the HC-SR501 PIR. It solves the "waving hand" problem and adds a layer of intelligence to your smart home.

• Effort Level: Beginner to Intermediate. The Bluetooth app makes it beginner-friendly, while UART integration offers depth for experts.

Virtual Technician & Wiring Guide

• ⚠️ Logic Level Warning: While the VCC pin accepts 5V, the RX/TX and OUT pins use 3.3V Logic. If connecting to a 5V Arduino Uno, you MUST use a logic level converter or a voltage divider on the RX line to prevent damaging the radar module.

• Pin Mapping:

  • VCC: 5V Power.

  • GND: Ground.

  • OUT: Digital Output (Simple High/Low).

  • TX: Transmits data to microcontroller.

  • RX: Receives commands (Use 3.3V!).

• Mounting: Do not mount behind metal. Plastic, wood, and drywall are transparent to the radar signals.

Accessories & Compatibility

• Included: 1x HLK-LD2410B Module.

• Recommended Hardware: ESP32 (Native 3.3V), Wemos D1 Mini, or USB-TTL Converter (for PC debug).

• Software: "HLKRadarTool" App (Android/iOS).

Helpful Tutorials & Resources

• HLK-LD2410B human presence - Radar Sensor Documentation
• HLK-LD2410B human presence - Buying Guide
• HLK-LD2410B human presence - User Guide

Frequently Asked Questions (FAQ)

• What is the difference between LD2410 and LD2410B? The "B" version has Bluetooth, allowing you to configure it wirelessly via a phone app.
• Does it work with Home Assistant? Yes, seamlessly via ESPHome (using UART or Bluetooth Proxy).
• Can I use it without a microcontroller? Yes, the "OUT" pin works just like a PIR sensor (High/Low) based on your configured settings.
• How do I change the distance range? Open the HLKRadarTool app, connect via Bluetooth, and adjust the "Moving" and "Static" distance gates.
• Does it see through walls? It can detect through thin walls/doors. You may need to reduce sensitivity to prevent false triggers from the next room.
• Can I turn off Bluetooth? Yes, there is a secure mode to disable Bluetooth after configuration to prevent unauthorized access.
• Is it safe? Yes, the transmission power is very low (milliwatts), safe for continuous human exposure.
• Why is the red LED blinking? A blinking light usually indicates it is in "Configuration Mode" or detecting a target (depending on firmware version).
• What is the baud rate? The default baud rate for UART is 256000.
• Can I use it outdoors? It is not waterproof. If placed in a waterproof plastic box, it can work, but rain may cause false triggers.
• Does it detect pets? Yes, it is sensitive enough to detect cats and dogs. You can try to tune the "Sensitivity Gates" to filter small movements.
• Does it interfere with Wi-Fi? No, 24GHz is far removed from 2.4GHz/5GHz Wi-Fi frequencies.
• Why does it say "Presence" when no one is there? Check for moving fans, curtains, or even AC airflow. Radar is extremely sensitive.
• How fast does it respond? Detection is almost instant (<0.5s). "OFF" delay is configurable (default 5s).
• Can I solder it directly? The module has 1.27mm pitch headers. It is hard to hand-solder; we recommend using the included cable.
• Is it better than LD2420? LD2410B is the "General Purpose" standard. LD2420 is newer/smaller but LD2410B has wider community support currently.
• Does it measure distance? Yes, the UART data stream provides the distance to the target in centimeters.
• Can I hide it inside a picture frame? Yes, as long as there is no metallic paint or foil backing.
• What power supply do I need? A stable 5V DC supply (USB or regulated source) is recommended. Noisy power can cause false triggers.
• Is the App free? Yes, HLKRadarTool is free on Play Store and App Store.