Data Sheet

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K-LD7

data sheet 12 / 2020 – Revision B

Page 1 / 23

PRODUCT INFORMATION

– Small and low cost digital 24 GHz radar motion detector

– Measures speed, direction, distance and angle

of moving objects

– Low current consumption

– Typical detection distance: 15 m for persons / 30 m for cars

– Target list output over serial interface

– Integrated FFT signal processing with tracking

– 4 conﬁgurable digital outputs

– Power supply range from 3.2 to 5.5 V

– 3 × 4 patch antenna with 80 °/ 34 ° beam aperture

– Distance triggered movement detection applications

– Simple gesture recognition

– Indoor and outdoor lighting control applications

– Pedestrian counting

– Trafﬁc counting

The K-LD7 is a fully digital low cost Doppler radar that can mea-

sure speed, direction, distance and angle of moving objects in

front of the sensor. The digital structure and wide power supply

range make it very easy to use this sensor in any stand-alone or

MCU based application.

The sensor includes a 3 × 4 patch antenna radar front-end with

an asymmetrical beam and a powerful signal processing unit with

four conﬁgurable digital outputs for signal detection information. A

built-in tracking ﬁlter makes the sensor output even easier to use.

The serial interface features the possibility to read out a target list

with speed, direction, distance and angle information of all moving

objects in front of the sensor or to digitally conﬁgure the sensors

detection parameters.

There is no need to write own signal processing algorithms or

handle small and noisy signals. This module contains everything

what is necessary to build a simple but powerful motion detec-

tor with distance and angle information. A very small footprint of

38 × 25 × 13.5 mm gives maximum ﬂexibility in the product develop-

ment process. For fast prototyping an evaluation kit (K-LD7-EVAL)

is available which features powerful signal visualization on a PC.

Features

Applications

Description

data sheet

K-LD7

digital radar transceiver

Figure 1: Block diagram

signal processing unit

voltage regulator

detect

out 1

out 2

out 3

serial interface

K-LD7

24.05–24.25 GHz

Rx1

Rx2

Block Diagram

Summary of content (23 pages)

PAGE 1
data sheet K-LD7 digital radar transceiver Features – Small and low cost digital 24 GHz radar motion detector – Measures speed, direction, distance and angle of moving objects – Low current consumption – Typical detection distance: 15 m for persons / 30 m for cars – Target list output over serial interface – Integrated FFT signal processing with tracking – 4 configurable digital outputs – Power supply range from 3.2 to 5.
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Characteristics Parameter Conditions / Notes Symbol Min Typ Max Unit Operating Conditions Supply voltage Vcc 3.2 5.5 RMS current Depending on speed range setting Icc 20 60 mA Peak current At start-up Ipp 200 mA 116 V Operating temperature TOp -40 +85 °C Storage temperature TSt -40 +105 °C Non-condensing, given by design RH 10 90 % Tamb = -40 ° C .. + 85 ° C fTX 24.050 24.
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TA B L E O F CONTENTS Product Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Applications. . Description. . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Characteristics. . . . . . . .
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5 4 9 8 7 6 11 10 ANTENNA DIAGRAM CHARACTERISTICS This diagram shows module sensitivity in both azimuth and elevation directions. It incorporates the transmitter and receiver antenna characteristics.
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T H E O R Y O F O P E R AT I O N Overview Processing The K-LD7 is a Doppler radar sensor and consists of an analogue RF frontend and a powerful signal processor with tracking and a fully digital serial interface. The RF frontend features one transmitter with a modulation input and two I/Q receivers. The signal processing unit modulates the frontend with a frequency step (FSK modulation) and samples the analogue I/Q Doppler signals for both transmit frequencies and for both receiving antennas.
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Speed and d irection m easurement 1 Angle measurement Dieses Dokument ist unser geistiges Eigentum. Es darf ohne unsere ausdrückliche Genehmigung weder kopiert, vervielfältigt oder verwertet, noch an Dritte weitergegeben werden. Zuwiderhandlung ist strafbar und wird strafrechtlich verfolgt. Copyright reserved! © RFbeam Microwave Every moving object in front of the sensor generates a Doppler frequency at the analogue outputs of the RF A frontend.
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Raw targets and tracking filter A real object generates not only one raw target point. A moving person for example generates several raw target points with different speeds and different distances created by the torso, the legs and the arms. This generates a so called point cloud of different raw targets from one object. Depending on the environment where the sensor is used it will also see more or less reflexions generated by the moving object.
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A P P L I C AT I O N I N F O R M AT I O N Stand-alone operation With standard settings the sensor is optimized for indoor detection of persons. The K-LD7 features four digital outputs which can directly be used without the need of an MCU. The digital outputs are per default configured in the following way: Table 2: Default digital output description Pin. No. Name Config Description 2 Digital out 0 Detection Digital detection output.
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Radar settings Speed range The K-LD7 features different parameters to adjust the functionality of the sensor to the needs of different applications. All parameters are stored in the radar parameter structure which can be read and write over the serial interface. The structure and serial protocol is described in the chapter Instruction Set Description on page 13. The speed range parameter defines the maximum unambiguous speed measurement of the sensor.
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Threshold offset The threshold offset is adjustable and defines the distance in dB between the noise floor of the raw FFT data and the threshold line. The processing in the K-LD7 searches for raw targets that are above this threshold line. The smaller the offset the more raw targets will be found by the processing and the more sensitive the sensor will be. A higher offset will reduce the sensitivity and the number of raw targets. Figure 9: Low vs.
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Detection settings Detection filter The last processing step in the K-LD7 generates a detection output based on a set of adjustable parameters. The information about the detection is available in the DDAT structure or on the digital outputs. The parameters are all located in the radar parameter structure which is described in detail in chapter Parameter structure on page 17. Table 6: Detection filter parameters Parameter name Affected data packets Description Min. / max.
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Digital outputs The sensor features four digital outputs to signal detection. The digital output 0 always signals if there was a valid detection. The function of the outputs 1 to 3 is configurable over the radar parameter structure. It is possible to route the values of the detection data structure DDAT to these outputs. Table 7: Routable functions for digital outputs 1 to 3 Function Description Direction Signals the direction of the detected target.
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INSTRUCTION SET DESCRIPTION Hardware Layer The hardware layer is based on a simple UART connection with a configurable baud rate. The sensor always starts up with its default baud rate. The default baud rate can be changed over the INIT command as described in the chapter Connection.
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Data output Figure 14: Data output Server (Radar ) Client ( Host) GNFD (TDAT, DONE) The client can request data messages with the GNFD command. Depending on the bits set in the GNFD command the enabled data messages will be sent out for the next acquired frame.
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Presentation Layer All commands and messages sent have the format described in table below. Table 9: Packet format Description Datatype Length Header The header describes the command or message type (e.g. RADC, RMRD, …) ASCII character 4 Bytes Payload Length The payload length is always sent even if the payload is zero. It is sent as little endian (LSB first). UINT32 4 Bytes Payload The payload is message and command dependent. If the payload includes datatypes (e.g.
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Parameter structure The radar has a set of parameter which can be modified with commands. The structure can be read out by the GRPS command and set by the SRPS command. Table 12: Radar parameter structure Description Datatype Length Values Default Software Version STRING 19 Zero-terminated String K-LD7_APP-RFB-XXXX Base frequency UINT8 1 0 = Low, 1 = Middle, 2 = High 1 = Middle Maximum speed UINT8 1 0 = 12.
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Messages This chapter provides detailed information about the messages of the K-LD7. Table 13: Application messages Header RADC Payload Length 3072 Description Raw ADC values It is recommended to use the highest baudrate when reading out RADC packets. RFFT 1024 Raw FFT It is recommended to use the highest baudrate when reading out RFFT packets.
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Commands This chapter provides detailed information about the commands. Table 14: Application commands Header Payload Length Description Values INIT 4 Start of connection 0 = 115200, 1 = 460800, 2 = 921600, 3 = 2000000, 4=3000000 GNFD 4 Get next frame data Binary coded bit-field.
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Communication example Figure 17: Example INIT command with 115200 baud host to radar radar to host Header: INIT 0x49 0x4E 0x49 Length: 4Byte 0x54 0x04 Header: RESP 0x52 0x45 0x53 0x00 0x00 Payload 4Byte: value 0 = 115200 baud 0x00 0x00 0x00 Length: 1Byte 0x50 0x01 0x00 0x00 0x00 0x00 Payload 1Byte: value 0 = OK 0x00 0x00 Figure 18: Example GNFD command with TDAT message host to radar radar to host radar to host Header: GNFD 0x47 0x4E 0x46 Length: 4Byte 0x44 0x04 0x50 0x01 0x
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I N T E G R AT O R S I N F O R M AT I O N Installation Instruction Mechanical enclosure It is possible to hide the sensor behind a so called radome (short for radar dome) to protect it from environmental influences or to simply integrate it in the case of the end product. A radar sensor can see trough different types of plastic and glass of any colour as long as it is not metallized. This allows for a very flexible design of the housing as long as the rules below are observed. – Cover must not be metallic.
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United States (FCC) and Canada (ISED) This module has been granted modular approval for fixed and/or mobile applications by FCC and ISED. Testing for the modular approval has been performed with the 10m range setting for all available frequency channels which represents the maximum TX emission configuration with the complete used bandwidth. This setup can easily be used by the customer for certification purposes. Modification to this product will void the users’ authority to operate this equipment.
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Europe (CE-RED) This module is a Radio Equipment Directive assessed radio module that is CE complaint and have been manufactured and tested with the intention of being integrated into a final product. According to the RED every final product that includes a radio module is also a radio product which falls under the scope of the RED. This means that OEM and host manufacturers are ultimately responsible for the compliance of the host and the module.
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OUTLINE DIMENSIONS Figure 20: Outline dimensions in millimetre 38 0.74 0.64 12.5 B (4:1) 25 20.8 B X1 Pin1 (3x2.54) O R D E R I N F O R M AT I O N 11.2 6 2.3 0 0 2.37 18.5 34.63 0.64 X2 Pin1 (8x2.54) Project XX YY Object R XX YY Material Surface The ordering number consists of different parts with the structure below Tolerance State Drawing Nr.