HLK-LD2450 24GHz mmWave Radar Sensor - Human Motion Trajectory Tracking Module

Specifications

• Model: HLK-LD2450 (24GHz mmWave).

• Detection Type: Motion Tracking + Coordinates (X, Y, Speed).

• Target Count: Tracks up to 3 Targets simultaneously.

• Sensing Distance: up to 6 Meters.

• Radar Frequency: 24 GHz (ISM Band).

• Interface: UART Serial (Baud Rate: 256000).

• Connector: 4-Pin (1.25mm Pitch) - Check if cable is included in your specific pack.

• Voltage: 5V DC (Typ).

• Viewing Angle: ±60° (Horizontal), ±35° (Vertical).

Key Applications & Projects

• Zone Automation: Divide a large living room into virtual "zones" (Sofa, TV, Dining) and trigger different devices based on exactly where the person is standing.

• Smart Security: Distinguish between a person walking towards the door vs. walking past it.

• People Counting: Approximate counting of moving people in a corridor or hallway.

• Gesture Control: Basic hand wave tracking based on speed and approach data.

Project Evolution

• The Bottleneck: Simple sensors can't tell if you are in the Kitchen or the Living Room if it's an open floor plan.

• The Upgrade: The LD2450 outputs coordinates. With ESPHome, you can define: "If Target is at X>2m, turn on Kitchen Light." It gives you spatial awareness previously only possible with cameras.

• Effort Level: Advanced. Requires parsing Serial data or using an ESPHome component (YAML configuration).

Virtual Technician & Setup Guide

• Connection:

  • VCC: 5V.

  • GND: Ground.

  • TX: Connect to MCU RX.

  • RX: Connect to MCU TX.

• Baud Rate: The default baud rate is 256000. Ensure your microcontroller (ESP32) is set to this high speed, or you will see garbage data.

• Mounting: Mount it vertically at a height of 1.5m - 2m for the best coordinate tracking.

• App Visualisation: Use the "HLKRadarTool" app (via Bluetooth, if module supports BT, or Serial adapter) to see the tracking map in real-time.

Accessories & Compatibility

• Included: 1x HLK-LD2450 Radar Module.

• Required: ESP32/ESP8266 (for Home Assistant), 4-Pin 1.25mm Cable (if not included).

• Related: HLK-LD2410 (for static breathing detection).

Helpful Tutorials & Resources

• HLK-LD2450 ESPHome YAML Configuration

• HLK-LD2450 human presence - Radar Sensor Documentation
• HLK-LD2450 human presence - Buying Guide
• HLK-LD2450 human presence - Starter Guide

Frequently Asked Questions (Technical SEO)

• What is the difference between LD2410 and LD2450? The LD2410 is best for Static Presence (detecting a sleeping person). The LD2450 is best for Motion Tracking (outputting X/Y coordinates of moving people). They serve different purposes.
• Does it detect stationary people? It is less sensitive to pure static "breathing" than the LD2410. The LD2450 is optimised for tracking movement and location. If you sit perfectly still for a long time, it might lose the track.
• How many people can it track? It can simultaneously track and output coordinates for up to 3 distinct targets.
• Can I use this with Home Assistant? Yes! It is fully supported in ESPHome. You can feed the X/Y coordinates into Home Assistant to create visual maps or zone triggers.
• Does it have Bluetooth? Some versions have Bluetooth for App configuration, but the primary data stream is via UART Serial.
• What connector does it use? It uses a tiny 1.25mm pitch 4-pin connector. Standard 2.54mm Dupont wires will NOT fit directly. You need the specific cable.
• Does it work through walls? Yes, 24GHz waves penetrate thin walls, plastic, and wood. It can be hidden inside a casing.
• What is the baud rate? The default is 256000 bps. This is non-standard, so ensure your code specifies this exact rate.
• Can I adjust the range? Yes, via the serial configuration or App, you can set the maximum detection distance (up to 6m).
• Is it affected by fans? Like all Doppler radars, moving fans can cause interference. However, the tracking algorithm tries to filter out non-human movement better than basic PIRs.
• Does it preserve privacy? Yes, unlike a camera, it only sees "dots" and coordinates. It cannot record video or recognise faces, making it ideal for bathrooms or bedrooms.
• What is the coordinate origin? The sensor itself is (0,0). X is horizontal (left/right), and Y is vertical distance (forward).
• Can I use it outdoors? It is not waterproof. If placed in a waterproof plastic box, it can work outdoors, but rain/trees might trigger it.
• Does it get hot? It warms up slightly, but not as much as older 5.8GHz sensors.
• Is the antenna directional? Yes, the 2x2 antenna array gives it a specific field of view (~60°). It does not detect well behind the board.
• Can I use it with Arduino Uno? The baud rate (256000) is very high for SoftwareSerial on a standard Uno. It is highly recommended to use a board with Hardware Serial, like ESP32 or Mega.
• Does it measure speed? Yes, the data packet includes the velocity of the target (moving towards or away).
• Why does the track "jump"? Radar reflections can sometimes bounce off metal objects (multipath), causing the coordinate to jitter. Software filtering in ESPHome helps smooth this out.
• What is the power consumption? It typically draws about 150mA at 5V.
• Is this the "2B" or "2C" version? The module shown is the standard LD2450 module. Always check the specific firmware version in the App for feature support.