HLK-LD2410C 24GHz mm Wave Human Presence Sensor - Bluetooth, Pre-Soldered Header

specifications

• Model: HLK-LD2410C (24GHz mmWave).

• Detection Type: Movement + Static Presence (Breathing/Micro-motion).

• Sensing Distance: up to 5 Meters (Static Presence), up to 6 Meters (Motion).

• Radar Frequency: 24.0 GHz ~ 24.25 GHz (ISM Band).

• Configuration: Bluetooth App (HLKRadarTool) or UART Serial.

• Voltage: 5V DC (Accepts 5V-12V).

• Output: 3.3V Logic Level (High = Presence, Low = Absent).

• Angle: ±60°.

• Connector: 5-Pin Header (2.54mm Pitch) - Pre-Soldered.

Key Applications & Projects

• True Smart Lighting: Keep lights ON in the bathroom or office even if the person is sitting perfectly still.

• Home Assistant (ESPHome): The gold standard sensor for "Room Occupancy" automations in Home Assistant.

• Elderly Care: Monitor if a person has been in the same spot (e.g., bed or chair) for unusual periods.

• Security: Hide the sensor behind plastic or drywall (it sees through obstacles) for invisible monitoring.

Project Evolution)

• The Bottleneck: PIR sensors rely on heat and large movements. They fail in hot rooms or with stationary subjects.

• The Upgrade: The LD2410C uses FMCW Radar. It divides the room into "Gates" (distance zones). You can tell the sensor to ignore a spinning fan at 3 meters but detect a person breathing at 2 meters. This granular control is impossible with PIR.

• Effort Level: Beginner/Intermediate. Easy to wire (VCC, GND, OUT). Tuning is done via the easy-to-use phone App.

Virtual Technician & Setup Guide

• Pinout:

  • VCC: 5V Power.

  • GND: Ground.

  • OUT: Digital Output (High when presence detected).

  • TX/RX: Serial pins for advanced UART configuration (optional).

• App Setup: Download "HLKRadarTool" from the App Store/Play Store. Power the module, enable Bluetooth on your phone, and connect. No pairing code is usually needed (or try 'HiLink').

• Mounting: Radar waves pass through plastic but are blocked by metal. Do not mount it inside a metal enclosure.

Accessories & Compatibility

• Included: 1x HLK-LD2410C Module (Pre-Soldered).

• Required: 5V Power Supply.

• Compatible: ESP32, Arduino, Raspberry Pi, Home Assistant (ESPHome).

Helpful Tutorials & Resources

• Integrating LD2410 with Home Assistant (ESPHome)

Frequently Asked Questions (Technical SEO)

• What is the difference between this and a PIR sensor? PIR detects heat movement and fails if you stay still. This mmWave sensor detects "Static Presence" (like breathing), ensuring lights stay on even when you are motionless.
• Does it require a microcontroller to work? No. Out of the box, the "OUT" pin goes HIGH (3.3V) when presence is detected. You can use this directly to trigger a relay or LED without any coding.
• How do I configure the range and sensitivity? You can use the free HLKRadarTool mobile app via Bluetooth. It allows you to set sensitivity for different distance "gates" (zones).
• Can I turn off the Bluetooth after configuration? Yes, via the App or UART commands, you can disable Bluetooth to save power or security, though it's usually left on for easy tweaking.
• Does it work through walls? Yes, 24GHz radar penetrates thin walls, plastic, wood, and glass. It will NOT pass through metal or thick concrete.
• Does it interfere with Wi-Fi? No, it operates at 24GHz, which is far away from standard Wi-Fi frequencies (2.4GHz and 5GHz).
• Is the "OUT" pin 5V or 3.3V? The logic output level is 3.3V, which is safe for ESP32 and Raspberry Pi. It is also compatible with 5V Arduino inputs (which will read 3.3V as High).
• Can I use this with Home Assistant? Yes! It is fully supported in ESPHome. You can connect the TX/RX pins to an ESP32 and get full control over sensitivity and distance directly in Home Assistant.
• What is the "C" in LD2410C? The "C" version has the standard 2.54mm pin spacing. The older "B" version had tiny 1.27mm pins that were difficult to use.
• Does it detect pets? Yes, it is very sensitive. However, you can use the App to adjust the sensitivity thresholds to try and filter out smaller pets, though large dogs will likely trigger it.
• Why does it stay ON when no one is there? This is usually due to interference (fans, moving curtains) or high sensitivity. Use the App to visualize the "noise" floor and raise the sensitivity threshold slightly above it.
• Can I use it outdoors? Technically yes, if protected from water (in a plastic box). However, rain, swaying trees, or bugs might cause false triggers.
• What is the maximum range? It can detect moving targets up to ~6 meters and static (sitting) targets up to ~5 meters.
• Does it get hot? It may get slightly warm during operation, which is normal for mmWave chips. Ensure it is not wrapped in thermal insulation.
• Can I mount it behind a mirror? Yes, as long as the mirror does not have a metal backing (most standard mirrors do have silver/metal backing, which blocks it). Two-way mirrors or plain glass work fine.
• How fast is the response time? It is almost instant for detection (<0.5s). The "off" time (delay) can be configured in the App.
• Does it measure distance? Internally yes, but the standard OUT pin just gives a Yes/No. To get the specific distance to the target, you must use the UART (TX/RX) data stream.
• Is the soldering reliable? Yes, this is the factory-soldered version, ensuring clean, solid joints on the header pins, unlike manual hand-soldering.
• Can I use multiple sensors in one room? Yes, but try to space them at least 1-2 meters apart to prevent cross-interference between their radar pulses.
• What is the power consumption? It consumes roughly 80mA at 5V. It is efficient enough for USB power but maybe too high for small coin-cell batteries.