Hi-Link HLK-LD2410B Radar Module User Manual

Shenzhen Hi-Link Electronic Co., Ltd.
HLK-LD2410B
Radar Module User Manual

Product introduction

HLK-LD2410B is a high-sensitivity 24GHz human presence status radar module developed by Hi-link Electronics. Its working principle is to use FMCW frequency-modulated continuous wave to detect human targets in the set space. Combined with radar signal processing and accurate human body sensing algorithms, it realizes high-sensitivity human presence status sensing, and can identify human bodies in motion and stationary states. And auxiliary information  such as the distance of the target can be calculated.
This product is mainly used in indoor scenes to sense whether there is a moving or micro moving human body in the area, and output the detection results in real time. The farthest sensing distance can reach 5 meters, and the distance  resolution is 0.75m. Provides a visual configuration tool, which can easily configure the sensing distance range, sensing sensitivity in different intervals and unmanned delay time, etc., to adapt to different specific application needs.  Support GPIO and UART output, plug and play, and can be flexibly applied to different smart scenarios and terminal products.

Product features and benefits

2.1 Features

• Plug and play, easy assembly
• The longest sensing distance is up to 5 meters
• Large detection angle, coverage up to ±60 degrees
• Accurate identification within the interval, support the division of the sensing range, and shield the interference outside the interval
• Multi-level intelligent parameter adjustment can be realized through Bluetooth or serial port to meet the needs of scene changes
• Visual debugging and configuration tools
• Small and simple, the minimum size is only 7mmx35mm
• Supports various installation methods such as ceiling hanging and wall hanging
• 24GHz ISM band, can be certified by FCC and CE spectrum regulations
• The ultimate cost-effective choice

2.2 Solution advantage
The HLK-LD2410B human body radar module adopts 24GHz millimeter wave radar sensor technology. Compared with other solutions, it has obvious advantages in human body sensing applications:

1. In addition to being sensitive to moving human bodies, it can also sensitively sense static, micro-moving, sitting and lying human bodies that cannot be identified by traditional solutions;
2. It has good environmental adaptability, and the sensing effect is not affected by the surrounding environment such as temperature, brightness, humidity and light fluctuations;
3. It has good shell penetration and can be hidden in the shell to work without opening holes on the surface of the product, which improves the aesthetics of the product;
4. It can flexibly configure the farthest sensing distance and the sensitivity on each distance door to achieve flexible and fine personalized configuration;
5. With the Bluetooth function, you can directly use the APP to debug the radar parameters without catching the serial port.

| Infrared solution| Visual solution| Ultrasonic wave| Lidar| Millimeter wave radar
---|---|---|---|---|---
Application flexibility| | | | |
Resistance to environmental influences (weather light,

etc.)

| | | | |
Detection speed| | | | |
Detection accuracy| | | | |
Resolution| | | | |
Directionality| | | | |
Detection distance| | | | |
Ability to penetrate material| | | | |
Dimension| | | | |
Cost| | | | |

Good Common Weak

Figure 2 Comparison of millimeter wave radar scheme and other schemes

Application scenarios

The HLK-LD2410B human body radar module can detect and identify the human body in motion, fretting, standing, sitting and lying down. It supports multi-level parameter adjustment and can be widely used in various AIoT scenarios. The common types are as follows:

• Human body sensor light control
  It senses whether there is someone in the space, and automatically controls lights, such as lighting equipment in public places, various sensor lights, bulb lights, etc.

• Human body induction wake-up of advertising screen and other equipment
  Automatically turn on when people come, and automatically sleep when no one comes to save power, information delivery is more accurate and efficient.

• Life safety protection
  UV lamp work protection, to prevent the UV lamp from being turned on when there are people around and causing personal injury; Automatic detection and alarm of dangerous places to prevent people from entering specific high-risk spaces, such as high-risk places entered by personnel from coal mine blasting.

• Smart home appliances
  When there is no one in the room for a long time, the TV, air conditioner and other electrical appliances are automatically turned off, saving energy and safety.

• Intelligent security
  Detection and identification of people intruding, staying, etc. within the specified range.

Hardware description

4.1 Dimensions

Module size: 7mmx35mm, 5 pin holes are reserved in the hardware (the factory default does not match the pins)
The pin hole diameter is 0.6mm, and the pin spacing is 1.27mm.

4.2 Pin definition

human presence: output low level
2| UART_Tx| Serial Tx| Serial Tx pin
3| UART_Rx| Serial Rx| Serial Rx pin
4| GND| Power ground| Power ground
5| VCC| Power input| Power input 5V

Table 1 Pin Definition Table

Use and configuration

5.1 Typical application circuit
The HLK-LD2410B module directly outputs the detected target state through an IO pin (someone is high, no one is low), and it can also output the detection result data through the serial port according to the specified protocol. The serial port output data includes: Target status and distance auxiliary information, etc., users can use it flexibly according to specific application scenarios. The power supply voltage of the module is 5V, and the power supply capacity of  the input power supply is required to be greater than 200mA.
The module IO output level is 3.3V. The default baud rate of the serial port is 256000, 1 stop bit, and no parity bit.
5.2 The role of configuration parameters
The user can modify the configuration parameters of the module through the serial port of the HLK-LD2410B to adapt to different application requirements, and the configuration content will not be lost when the power is turned off.

The configurable parameters include the following:

• farthest detection distance
  Set the farthest detectable distance, only human targets that appear within this farthest distance will be detected and output the result.
  Set in units of distance gates, and each distance gate is 0.75m.
  Including the farthest door for motion detection and the farthest door for static detection, the setting range is 1 to 8. For example, if the farthest door is set to 2, only if there is a human body within 1.5m will it effectively detect and output the result.

• Sensitivity
  Only when the detected target energy value (range 0~100) is greater than the sensitivity value will it be determined that the target exists, otherwise it will be ignored.
  The sensitivity value can be set from 0 to 100. The sensitivity of each range gate can be independently set, so that the detection in different distance ranges can be precisely adjusted, local accurate detection or filtering of interference sources in specific areas. In addition, if the sensitivity of a certain distance gate is set to 100, the effect of not recognizing the target under the distance gate can be achieved. For example, if the sensitivity of distance  gate 3 and distance gate 4 is set to 20, and the sensitivity of other distance gates is set to 100, it is possible to detect only the human body within the range of 2.25-3.75m from the distance module.

• no-one duration
  When the radar outputs the result from man to no man, it will report man for a period of time. If there is no man in the radar test range during this time period, the radar will report no man; if the radar detects man during this time period, it will be refreshed again. This time, in seconds. It is equivalent to the unmanned delay time. After the person leaves, the output state will be unmanned only after the person has left the system for more than this duration.

5.3 Visual configuration tool description
In order to facilitate the user to test and configure the module quickly and efficiently, a PC configuration tool is provided. The user can use this tool software to connect the serial port of the module, read and configure the parameters of  the module, and receive the detection results reported by the module. Data, and real-time visual display, which greatly facilitates the use of users.

How to use the host computer tool:

• Use the USB to serial port tool to connect the module serial port correctly;
• Select the corresponding serial port number in the host computer tool, set the baud rate to 256000, select the engineering mode, and click to connect the device;
• After the connection is successful, click the Start button, and the graphical interface on the right will display the test results and data;
•  After connecting, when the start button is not clicked, or click stop after starting, the mode parameter information can be read or set;

Note: The parameters cannot be read and configured after clicking start, and configuration can only be performed after stopping.
The interface and common functions of the host computer tool are as follows:

The ball is the target status output indication: red means there is a moving target; purple means there is a stationary target; green means no one.

5.4 Mounting method and sensing range

5.5 Installation conditions
Confirm the minimum installation clearance
If the radar needs to be installed with a casing, the casing must have good wave-transmitting properties at 24GHz, and cannot contain metal materials or materials that have a shielding effect on electromagnetic waves.
Installation environment requirements
This product needs to be installed in a suitable environment. If it is used in the following environments, the detection effect will be affected:

• There are non-human objects that are continuously moving in the sensing area, such as animals, continuously swinging curtains, large green plants facing the air outlet, etc.
• There is a large area of strong reflectors in the sensing area, and the strong reflectors will cause interference to the radar antenna.
• When installing on the wall, external interference factors such as air conditioners and electric fans on the top of the room need to be considered.

Precautions during installation

• Try to ensure that the radar antenna is facing the area to be detected, and the surrounding area of the antenna is open and unobstructed
• To ensure that the installation position of the sensor is firm and stable, the shaking of the radar itself will affect the detection effect.
• To ensure there is no movement or vibration on the back of the radar. Due to the penetrating nature of radar waves, the back lobe of the antenna signal may detect moving objects behind the radar. A metal shield or metal  backplane can be used to shield the radar back lobe and reduce the impact of objects on the back of the radar
• The theoretical distance accuracy of radar is the result obtained through special algorithm processing on the basis of the physical resolution of 0.75 meters. Due to the difference in the size, state, and RCS of the target, the target  distance accuracy will fluctuate; at the same time, the longest distance will also fluctuate slightly.

Bluetooth instructions

6.1 Install software
Currently the APP supports Android and IOS platforms, you can download it from this link: https://www.pgyer.com/Lq8p (Android) You can also go to major app stores to search for “HLKRadarTools” and install it.

6.2 Instructions
Open the app, and the app searches for nearby radar devices. The broadcast name of the device is “HLK-LD2410B_xxxx” (xxxxxx is the last four digits of the mac address). After the module is successfully connected, you can view the radar information, or debug and save the parameters.
The use distance of the APP should not exceed the Bluetooth signal range (within 4 meters).

The process of modifying the radar parameters of the Bluetooth APP is the same as that of the PC host computer tool.

6.3 Bluetooth password
APP first connected to the password must be entered before the control, the default password is HI Link, you can in the parameter settings -> control password The default password is HI Link, which can be changed in Parameter Settings -> Control Password, the password is fixed at 6 bytes.
Note: Only V1.07.22091516 or newer versions support the password function.
6.4 OTA upgrade
When there is an update to the device firmware, the word upgradeable will appear on the firmware version, long press the version number to enter the upgrade screen; only V1.07.22091516 or newer versions are supported for upgrade.

The overall upgrade time takes 1~3 minutes. The upgrade must be done within 3m of the module, otherwise the upgrade will fail due to poor Bluetooth signal.
The module must not be powered off, restarted or forced to exit the app before the upgrade is completed, otherwise the upgrade will fail. If the upgrade fails If the upgrade fails, the radar program of the 2410B will be disabled and radar  detection will not be possible.
If the upgrade fails, please reboot the device and reconnect to the app, a “waiting for upgrade” message will appear on the device list.

6.5 Bluetooth communication protocol
The 2410B acts as a slave and is only allowed to be connected by one master.

receive
0000fff2-0000-1000-8000-00805f9b34fb| Write Without Response| App send, module receive

Once the app and 2410B Bluetooth connection and password check are successful, the module will start the transmission of radar data. The data transmitted by Bluetooth is identical to the Please refer to the document “HLK-LD2410B Serial Communication Protocol V1.05.pdf” for the exact same protocol as the serial port.
A successful connection to the App will send a Bluetooth password to the module for verification, only if the password is correct will the module start transmitting data. For more details, please refer to the Get Bluetooth permission section of the HLK-LD2410B Serial Communication Protocol.pdf.
6.6 Turn on Bluetooth again
The Bluetooth function of HLK-LD2410B is on by default, you can turn it off or on through the serial port protocol “HLK-LD2410B Serial Communication Protocol V1.05.pdf”. If Bluetooth has been turned off, or if the serial port is not available, powering off and then powering on the module more than 5 times in a row within 2~3s will turn Bluetooth on again.

Performance and electrical parameters

**Operating frequency| 24010MHz~ 24245MHz Compliant with FCC, CE, non- commission certification standards
---|---
Operating Voltage| DC 5~12V, power supply capacity>200mA
****Average operating current| ** 79 mA
Modulation| FMCW
**Interface| A GPIO, IO level 3.3V A UART
Target application| Human presence sensor
Detection distance| 0.75m ~ 6m, adjustable
Detection angle| ±60 °
Distance resolution| 0.75m
Sweep Bandwidth| 250MHz Compliant with FCC, CE, non-commission certification standards
Ambient temperature| -40 ~ 85℃
Dimensions**| 7mm x 35 mm

Table 2 Performance and electrical parameters table

Radom design guidelines

8.1 Effects of redoes on mm wave sensor performance

• Radar waves are reflected on the radiomen boundary
• Losses in total radar radiated or received power
• The reflected wave enters the receiving channel, affecting the isolation between the transmitting and receiving channels
• Reflections may degrade the standing wave of the antenna, further affecting the antenna gain
• Radar waves will suffer loss when propagated in the medium. In theory, the higher the frequency, the greater the loss will be
• Electromagnetic waves undergo a certain degree of refraction as they pass through a medium
• Affects the antenna’s radiation pattern, which in turn affects the sensor’s coverage

8.2 Radom design principles

• Structural shape of the radiomen
• The surface is smooth and flat, and the thickness is uniform. Such as plane or spherical surface. can not be uneven.
• If there is a surface coating, it must not contain metals or conductive materials.
• Directly above the antenna. the radiomen is parallel to the antenna plane.
• Height H from the antenna to the inner surface of the radiomen
• The ideal height is an integer multiple of the half wavelength of the electromagnetic wave in the air.
• ,where in is a positive integer,Co is the speed of light in vacuum, and f is the working center frequency.
• For example. the center frequency of 24.125GHz. its half wavelength in air is about 6.2nun.
• Radom thickness D
• The ideal thickness is an integer multiple of the half wavelength of the electromagnetic wave in the medium.
• where in is a positive integer and err is the relative permittivity of the radiomen material.
• For example. a certain ABS material err=2.5, its half wavelength is about 3.92nun.

8.3 Common materials

• Understand the material and electrical characteristics of the radiomen before designing
• The table on the right is for reference only, the actual value should be confirmed with the supplier
• Height H from the antenna to the inner surface of the radiomen
• If there is enough space, it is preferred to recommend 1 times or 1.5 times the wavelength
• For example, 12.4 or 18.6mm is recommended for 24.125GHz
• Error control: ±1.2mm
• Radom thickness D
• Recommended half wavelength, error control±20%
• If the thickness requirement of half wavelength cannot be met
• It is recommended to use low materials
• Thickness recommended 1/8 wavelength or thinner
• Influence of heterogeneous materials or multi-layer composite materials on radar performance, it is recommended to make experimental adjustments during design

Common material properties (based on 24.125GHz)

Medium| Er Typical value| Half wavelength (mm)| 1/8 wavelength (mm)| 1/10 wavelength (mm)
---|---|---|---|---
Air| 1.00| 6.20| 1.55| 1.24
ABS1| 1.50| 5.06| 1.27| 1.01
ABS2| 2.50| 3.92| 0.98| 0.78
PC material| 3.00| 3.58| 0.89| 0.72
PMMA acrylic 1| 2.00| 4.38| 1.10| 0.88
PMMA acrylic 2| 5.00| 3.| 0.69| 0.55
PVC hard| 4.00| 3.10| 0.78| 0.62
PVC soft| 8.00| 2.19| 0.55| 0.44
‘High density PE| I 2.40| 4.00| 1.00| 0.80
Low density PE| 2.30| 4.09| 1.02| 0.82
Quartz glass| 5| 2.77| 0.69| 0.55

Table 3 Common Material Properties of Radom’s

Revision records

Technical support and contact

Shenzhen Hi-Link Electronic Co.,Ltd
Address：1705, 1706, 1709A, Building E, Xinghua WORLD, Milne Community, Munshi Street, Longhead District, Shenzhen, China
Phone：(86) 755-23152658
Website：https://www.hlktech.net/
Any Changes expressly or modifications not approved by the party responsible for compliance could void the user’s authority to operate the equipment.
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including  interference that may cause undesired operation.
|Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a  residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there  is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

FCC Radiation Exposure Statement:
This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment .
This transmitter must not be co‐located or operating in conjunction with any other antenna or transmitter.
Integration instructions for host product manufacturers according to KDB 996369 D03 OEM
Manual v01
2.2 List of applicable FCC rules
CFR 47 FCC PART 15 SUBPART C&E has been investigated. It is applicable to the modular.
2.3 Specific operational use conditions
This module is stand-alone modular. If the end product will involve the Multiple simultaneously transmitting condition or different operational conditions for a stand-alone modular transmitter in a host, host manufacturer have to  consult with module manufacturer for the installation method in end system.
2.4 Limited module procedures
Not applicable
2.5 Trace antenna designs
Not applicable
2.6 RF exposure considerations
This equipment complies with FCC radiation exposure limits set forth for au uncontrolled environment .RF Exposure is exemption.
2.7 Antennas
This radio transmitter FCC ID: 2AD56HLK-LD2410B-P has been approved by Federal Communications Commission to operate with the antenna types listed below, with the maximum permissible gain indicated. Antenna types not included in this list that have a gain greater than the maximum gain indicated for any type listed are strictly prohibited for use with this device.

2.8 Label and compliance information
The final end product must be labeled in a visible area with the following” Contains
FCC ID: 2AD56HLK-LD2410B-P”
2.9 Information on test modes and additional testing requirements
Host manufacturer is strongly recommended to confirm compliance with FCC requirements for the transmitter when the module is installed in the host.
2.10 Additional testing, Part 15 Subpart B disclaimer
Host manufacturer is responsible for compliance of the host system with module installed with all other applicable requirements for the system such as Part 15 B

References

• Shenzhen Hi-Link Electronic Co., Ltd.
• HLKRadarTool

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