The Complete Guide to the HLK-LD2450 24GHz Multi-Target Tracking Radar Module

The HLK-LD2450 is a 24GHz FMCW (frequency-modulated continuous-wave) millimeter-wave radar module from Shenzhen Hi-Link, the sibling of the already-published HLK-LD2410. Where the LD2410 answers a yes/no “is someone there” question, the LD2450 tracks up to three separate moving targets simultaneously, each with its own X/Y coordinate and speed, streamed continuously over UART.

The numbers in this guide come from the Hi-Link LD2450 documentation as summarised in the existing text. I could not download the Hi-Link manual for this update, so the figures are not checked against it again.

LD2410 or LD2450: which do you need?

If you only need occupancy detection, the simpler LD2410 is cheaper and easier to integrate. Reach for the LD2450 when you need to know where someone is in a room, count multiple people, or detect direction of movement.

Specifications and Pinout

Dimensions

The LD2450 is a small module with a flat antenna on one side and a 5-pin header. Its sizes differ between makers, so measure yours before you design a case. Mount it flat and still, at a height where its ±60° field covers the room, and keep metal out of the beam. The coordinates are relative to the module, so the orientation is part of your calibration.

Source: the details come from the existing text of this guide and common practice, not from a datasheet read for this update.

Wiring to an ESP32

The module needs a genuine 5V supply (not 3.3V) but its UART logic level is 3.3V-safe for direct connection to an ESP32’s hardware UART. Cross TX/RX between the two devices.

Arduino code (HLK-LD2450 library by RBEGamer)

#include <HardwareSerial.h>
#include <LD2450.h>

HardwareSerial radarSerial(2);
LD2450 radar;

void setup() {
  Serial.begin(115200);
  radarSerial.begin(256000, SERIAL_8N1, 16, 17);
  radar.begin(radarSerial);
}

void loop() {
  radar.read();
  for (int i = 0; i < 3; i++) {
    if (radar.getTargetActive(i)) {
      Serial.printf("Target %d: x=%dmm y=%dmm speed=%dcm/sn",
        i, radar.getTargetX(i), radar.getTargetY(i), radar.getTargetSpeed(i));
    }
  }
  delay(100);
}

The exact method names vary slightly between the several community LD2450 libraries (RBEGamer/HLK-LD2450, darkjumpy/HLK-LD2450_Arduino_Library, Fiooodooor/HLK-LD245X all exist), check the specific library’s own examples, the wiring and 256000-baud UART protocol are the same regardless of which one you pick.

Practical Applications

• Room occupancy counting: track up to 3 people moving through a space.
• Smart lighting zones: turn on only the light near the tracked X/Y position, not the whole room.
• Fall/motion-pattern detection: speed and position data over time can flag unusual movement.
• Privacy-preserving presence: no camera involved, useful where a camera would raise privacy concerns.

Real gotchas

• It needs 5 V. The supply must give more than 200 mA. The UART levels are 3.3 V.
• The baud rate is fixed at 256000. A wrong baud rate gives garbage.
• Binary protocol. It does not send text. Use a library or parse the frames yourself, and check the frame header and tail.
• Three targets at most. More people are not tracked. Two people close together can merge into one.
• Only moving targets. The module tracks movement. A person who sits still can disappear from the list, unlike the LD2410.
• The coordinates depend on the mounting. X and Y are relative to the module, and the sign of the X axis depends on the version. Test with one person.
• Ghost targets. Reflections from walls and metal furniture can create false targets. Set zones and filter by speed.
• 10 frames a second. That is fine for presence and slow movement, but not for fast gestures.
• Range is about 6 m, with accuracy that falls at the edges of the ±60° field.

Safety notes

Conclusion

The LD2450 gives you real multi-target position tracking that a simple presence sensor like the LD2410 can’t, at the cost of a more involved binary UART protocol. Pair it with an ESP32’s hardware UART for reliable 256000-baud framing.