seeed studio MR24HPB1 Human Presence Radar User Manual

seeed studio MR24HPB1 Human Presence Radar User Manual

Overview

This document focuses on the use of the radar, the issues that need to be addressed at each stage to minimise design costs and increase product stability and improve the efficiency of project completion.
From hardware circuit reference design, radar antenna and housing layout requirements, how to differentiate between interference and multi-functional standard UART protocol outputs.
The radar is a self-contained space sensing sensor, consisting of RF antenna, radar chip and high speed main frequency MCU together with a module that relies on a stable and flexible superior algorithm architecture core to solve the user’s various scenario detection needs, which can be equipped with a host computer or host computer to flexibly output detection status and data, meeting several groups of GPIOs for custom development.

1. Principle of operation]

The radar transmits a millimetre wave signal in the 24G band, the measured target reflects the electromagnetic wave signal and demodulates the transmitted signal, which is then amplified, filtered and processed by ADC to obtain the echo demodulated signal data. The amplitude, frequency and phase of the echo signal are decoded in the MCU unit, which ultimately enables the measurement of target parameters (breathing, movement,
micro-motion, etc.) and scene evaluation.

2. Hardware Design Considerations

The radar needs to have a rated supply voltage of 4.9 – 6V and a rated current requirement of 200mA or more input under normal operating conditions. The power supply must be designed for a supply ripple of ≤ 100mv.

2.1. The power supply can be designed with the following circuit in mind

2.2. using the wiring diagram

Fig. 3 Schematic diagram of the radar module and peripheral connections

3. Antenna and housing layout requirements

PCBA: the radar needs to be kept ≥ 1mm higher than the other components.
Housing construction: need to maintain a distance of 2 – 5mm between the radar antenna face and the housing face.
Housing detection surface: non-metallic housing, needs to be flat and straight to avoid curved surfaces which can affect the performance of the entire swept surface area.

4. Static Protection

Radar products have electrostatic sensitive circuitry and are susceptible to electrostatic hazards, therefore they need to be adequately protected from static electricity during transport, storage, work and handling.
When handling the radar sensor, please wear anti-static gloves if possible.

5. Functional disturbances

5.1 Unoccupied state, abnormal output occupied

In normal conditions, the radar will accurately determine the presence of a sitting or sleeping body and output information on falls, breathing, vital signs etc.
A. Radar scanning area is large, doorway, boarded wall next door movement is detected. Adjustment method: reduce radar sensitivity, radar provides scene setting.
B. Radar underneath is facing a running air conditioner or fan. Adjustment method: adjust the radar position so that it is not directly in front of the air conditioner or fan.
C. Shifting objects caused by air conditioning winds. Adjustment method: cotton, non-metallic objects will not cause false alarms, metal objects need to be fixed.
D. The radar is not fixed, vibration causes false alarms. Avoid supporting shaking and vibration.
E. Occasional moving objects such as pets, birds, etc.
As the radar measures micro-movements, the sensitivity is very high and this interference cannot be excluded.
F. Power supply interference, resulting in occasional false alarms.
Try to keep the power supply current stable and reduce ripple.

5.2 Manned status, abnormal output unoccupied

Radar determines the presence of a human body by sending and receiving electromagnetic waves. The closer you are to the radar, the more accurate it is.
A. Human body out of radar range Radar scanning range with adjustment of mounting angle. Radar measurement range, in different environments with different electromagnetic wave reflection areas, the scanning area will vary slightly.
B. False output due to metal occlusion
Excessively thick desks and chairs, metal seats. It will block the electromagnetic wave penetration and cause misinterpretation.
C. Differences in scanning angles
The radar does not scan the torso area. This can lead to false positives.
D. Radar sensitivity is too low
The radar offers parameter adjustment to increase sensitivity for improvement.

6. Functions in detail

6.1. Function point descriptions

Functions

|

Status change time/function explanation

---|---

DP1: occupied/unoccupied

|

No one to occupied, report within 0.5s

Manned to unoccupied, no status output in 1-2 minutes or so

DP2: Some people are stationary / Some people are active

|

Static dynamic switching, reporting within

0.5 seconds

DP3: Someone close to the device / someone moving away from the device / someone moving without direction

|

Status output once every 2 seconds

DP4: Body movement amplitude parameter 0 – 100

|

Data output once every 5 seconds

Reference (description of output of body motion amplitude parameters)

DP5: Sensitivity setting 1 – 10 steps

|

Default scene mode, adapted to 10 positions of adjustment

DP7: Scene modes (bed, bathroom, hotel, bedroom, office, default mode)

|

Adapted to different scenarios according to the size of the area

DP8: No false alarm confirmation prompt

|

6.2. Description of the output of the body motion amplitude parameter

Body movement amplitude parameters

0%| None| Environmental unmanned
1%| Stationary (sleep)| Only breathing without body movement
2% – 30%| Micro-Movements| Only minor head or limb movements Movement
31% – 60%| Walking/fast body movements| Slower body movements
61% – 100%| Running/close range big moves| Rapid body movement

7. Description of the agreement

This protocol is used to communicate between a 24G millimetre wave sleep detection radar and a host computer.
This protocol outlines the radar workflow, provides a brief introduction to the interface protocol component architecture and gives the control commands and data required for the operation of the relevant radar, with the serial communication defined as follows.\

• Interface level: TTL
• Baud rate: 9600bps
• Stop bits: 1
• Data bits: 8
• Parity: None

8. Communication commands and parameter definitions

8.1 Definition and description of the frame structure

A. Frame structure definition

Starting Code

|

Length of data

|

Function codes

|

Address code 1

|

Address code 2

|

Data

|

Check Code

---|---|---|---|---|---|---

0X55

|

Lenth_L

|

Lenth_H

|

Command

|

Address_1

|

Address_2

|

Data

|

Crc16_L

|

Crc16_H

1 Byte

|

1 Byte

|

1 Byte

|

1 Byte

|

1 Byte

|

1 Byte

|

n Byte

|

1 Byte

|

1 Byte

B. Description of the frame structure
a. Start code: 1 Byte, fixed to 0X55.
b. Data length: 2 Byte, low byte before, high byte after.
Length = Data Length + Function Code + Address Code 1 + Address Code 2
+ Data + Checksum.
c. Function code: 1 Byte
Read command: 0X01
Write command: 0X02
Passive report command: 0X03
Active report command: 0X04
d. Address code: Address code 1 indicates the function classification, address code 2 indicates the specific function. See the description of address assignment and data information.
e. Data: n Byte
f. Checksum: 2 Byte, low byte before, high byte after.
CRC16 checksum is used, see Appendix 1 for reference code.

8.2. Description of address assignment and data information

24G Bio-aware radar interface content

 | Function

Code

| Address

code 1

| Address code

2

|

Data

|

Notes

1

|

Read command 0x01

|

Marking search 0x01

| Device ID

0x01

|  |

2

| Software

version 0x02

|  |

3

| Hardware

version 0x03

|  |

4

| Protocol

version 0x04

|  |
 |

Radar Information Search 0x03

| Environmental

status 0x05

|  |

11

| Signs

parameters 0x06

|  |

12

|

System parameter search 0x04

| Threshold

gear 0x0C

|  |
 | Scene setting

0x10

|  |

16

|  |  |

Threshold gear 0x0C

|

Enumeration range1~10

| Corresponding to

1 2 3 4 5 6 7

8 9 10 gears

(default 7)

The higher the gear, the more

24G Bio-aware radar interface content

 | Function

Code

| Address

code 1

| Address code

2

|

Data

|

Notes

 |

copy order 0x02

|

System parameters 0x04

|  |  | sensitive it is
 |

Scene setting 0x10

| Default mode 0x00|
 | Area detection (top

loading) 0x01

|
 | Bathroom (top

mounted) 0x02

|
 | Bedroom (top

loading) 0x03

|
 | Living room (top

mounted) 0x04

|
 | Office (top loading)

0x05

|
 | Hotel (top loading)

0x06

|
 | Other

functions 0x05

|

Reboot 0x04

|  |

17

|  |

Reporting module identification 0x01

| Device ID

0x01

|

12 Byte data

|

18

| Software

version 0x02

|

10 Byte data

|

19

| Hardware

version 0x03

|

8 Byte data

|

20

| Protocol

version 0x04

|

8 Byte data

|
27| Report radar| Environment| Unoccupied 00 FF FF|
24G Bio-aware radar interface content

 | Function

Code

| Address

code 1

| Address code

2

|

Data

|

Notes

28

|

Passive reporting of orders 0x03

| information 0x03| status 0x05| Someone is

stationary 01 00 FF

|

29

| Some people exercise

01 01 01

|

30

| Signs parameters

0x06

|

4 Byte Float data (see appendix 2)

|
 |

Reporting system information 0x04

| Threshold

gear 0x0C

| Current gear value

(0x01~0x0a)

|
 |

Scene setting 0x10

| Default mode 0x00|
 | Area detection (top

loading) 0x01

|
 | Bathroom (top

mounted) 0x02

|
 | Bedroom (top

loading) 0x03

|
 | Living room (top

mounted) 0x04

|
 | Office (top loading)

0x05

|
 | Hotel (top loading)

0x06

|
31|  |  |

Environment status 0x05

| Unoccupied 00 FF FF|

32

| Someone is stationary

01 00 FF

|
33| Some people exercise|
24G Bio-aware radar interface content

 | Function

Code

| Address

code 1

| Address code

2

|

Data

|

Notes

 |

Proactive reporting of commands 0x04

| Report radar information 0x03|  | 01 01 01|

34

| Motor signs parameters

0x06

|

4 Byte Float data

|
 |

Approaching away state 0x07

|

Fixed character 0x01

0x01

| None

0x01

|
 | Close to

0x02

|
 | Stay away

0x03

|
 |

Report other information 0x05

|

Heartbeat Pack 0x01

| Unoccupied 00 FF FF|
 | Someone is stationary

01 00 FF

|
 | Some people exercise

01 01 01

|
 | Abnormal

reset 0x02

|

0x0F

|

Description.

1. The read/write command is for the upper computer to send commands to the radar.
2.  The report command is for the radar to send information to the upper computer.
3. Fall sensitivity is 1~10, default is 4, the higher the level, the more sensitive it is.

Appendix 1: CRC check digit reference parsing codes

1. const unsigned char cuc_CRCHi[256]=
2. {

3.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
---|---|---|---|---|---|---|---|---|---|---|---|---
4.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
5.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
6.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
7.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
8.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
9.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
10.| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
11.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
12.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
13.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
14.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
15.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
16.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
17.| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
18.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
19.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
20.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x00,| 0xC1,| 0x81,| 0x40,
21.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
22.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,
23.| 0x00,| 0xC1,| 0x81,| 0x40,| 0x01,| 0xC0,| 0x80,| 0x41,| 0x01,| 0xC0,| 0x80,| 0x41,
24.| 0x00,| 0xC1,| 0x81,| 0x40|  |  |  |  |  |  |  |
25. };|  |  |  |  |  |  |  |  |  |  |  |
26.

27. const unsigned char cuc_CRCLo[256]=

28. {|  |  |  |  |  |  |  |  |  |  |  |  |
29.|  | 0x00,| 0xC0,| 0xC1,| 0x01,| 0xC3,| 0x03,| 0x02,| 0xC2,| 0xC6,| 0x06,| 0x07,| 0xC7,
30.|  | 0x05,| 0xC5,| 0xC4,| 0x04,| 0xCC,| 0x0C,| 0x0D,| 0xCD,| 0x0F,| 0xCF,| 0xCE,| 0x0E,
31.|  | 0x0A,| 0xCA,| 0xCB,| 0x0B,| 0xC9,| 0x09,| 0x08,| 0xC8,| 0xD8,| 0x18,| 0x19,| 0xD9,
32.|  | 0x1B,| 0xDB,| 0xDA,| 0x1A,| 0x1E,| 0xDE,| 0xDF,| 0x1F,| 0xDD,| 0x1D,| 0x1C,| 0xDC,
33.|  | 0x14,| 0xD4,| 0xD5,| 0x15,| 0xD7,| 0x17,| 0x16,| 0xD6,| 0xD2,| 0x12,| 0x13,| 0xD3,
34.|  | 0x11,| 0xD1,| 0xD0,| 0x10,| 0xF0,| 0x30,| 0x31,| 0xF1,| 0x33,| 0xF3,| 0xF2,| 0x32,
35.|  | 0x36,| 0xF6,| 0xF7,| 0x37,| 0xF5,| 0x35,| 0x34,| 0xF4,| 0x3C,| 0xFC,| 0xFD,| 0x3D,
36.|  | 0xFF,| 0x3F,| 0x3E,| 0xFE,| 0xFA,| 0x3A,| 0x3B,| 0xFB,| 0x39,| 0xF9,| 0xF8,| 0x38,
37.|  | 0x28,| 0xE8,| 0xE9,| 0x29,| 0xEB,| 0x2B,| 0x2A,| 0xEA,| 0xEE,| 0x2E,| 0x2F,| 0xEF,
38.|  | 0x2D,| 0xED,| 0xEC,| 0x2C,| 0xE4,| 0x24,| 0x25,| 0xE5,| 0x27,| 0xE7,| 0xE6,| 0x26,
39.|  | 0x22,| 0xE2,| 0xE3,| 0x23,| 0xE1,| 0x21,| 0x20,| 0xE0,| 0xA0,| 0x60,| 0x61,| 0xA1,
40.|  | 0x63,| 0xA3,| 0xA2,| 0x62,| 0x66,| 0xA6,| 0xA7,| 0x67,| 0xA5,| 0x65,| 0x64,| 0xA4,
41.|  | 0x6C,| 0xAC,| 0xAD,| 0x6D,| 0xAF,| 0x6F,| 0x6E,| 0xAE,| 0xAA,| 0x6A,| 0x6B,| 0xAB,
42.|  | 0x69,| 0xA9,| 0xA8,| 0x68,| 0x78,| 0xB8,| 0xB9,| 0x79,| 0xBB,| 0x7B,| 0x7A,| 0xBA,
43.|  | 0xBE,| 0x7E,| 0x7F,| 0xBF,| 0x7D,| 0xBD,| 0xBC,| 0x7C,| 0xB4,| 0x74,| 0x75,| 0xB5,
44.|  | 0x77,| 0xB7,| 0xB6,| 0x76,| 0x72,| 0xB2,| 0xB3,| 0x73,| 0xB1,| 0x71,| 0x70,| 0xB0,
45.|  | 0x50,| 0x90,| 0x91,| 0x51,| 0x93,| 0x53,| 0x52,| 0x92,| 0x96,| 0x56,| 0x57,| 0x97,
46.|  | 0x55,| 0x95,| 0x94,| 0x54,| 0x9C,| 0x5C,| 0x5D,| 0x9D,| 0x5F,| 0x9F,| 0x9E,| 0x5E,
47.|  | 0x5A,| 0x9A,| 0x9B,| 0x5B,| 0x99,| 0x59,| 0x58,| 0x98,| 0x88,| 0x48,| 0x49,| 0x89,
48.|  | 0x4B,| 0x8B,| 0x8A,| 0x4A,| 0x4E,| 0x8E,| 0x8F,| 0x4F,| 0x8D,| 0x4D,| 0x4C,| 0x8C,
49.|  | 0x44,| 0x84,| 0x85,| 0x45,| 0x87,| 0x47,| 0x46,| 0x86,| 0x82,| 0x42,| 0x43,| 0x83,
50.|  | 0x41,| 0x81,| 0x80,| 0x40|  |  |  |  |  |  |  |
51.| };|  |  |  |  |  |  |  |  |  |  |  |
52.

54. static unsigned short int us_CalculateCrc16(unsigned char *lpuc_Frame, unsigned short i nt lus_Len)

55. {

56.       unsigned char luc_CRCHi = 0xFF;

57.       unsigned char luc_CRCLo = 0xFF;

58.       int li_Index=0;

59. ---

    60.      while (lus_Len–)
    61.      {
    62.           li_Index = luc_CRCLo ^ *( lpuc_Frame++);
    63.           luc_CRCLo = (unsigned char )( luc_CRCHi ^ cuc_CRCHi[li_Index]);
    64.           luc_CRCHi = cuc_CRCLo[li_Index];
    65.      }
    66.      return (unsigned short int )(luc_CRCLo << 8 | luc_CRCHi);
    67. }

Appendix 2: Analysis codes for motor sign parameters

typedef union
2. {
3. unsigned char Byte[4];
4. float Float;
5. }Float_Byte;
6.
7. void main()
8. {
9. Float_Byte fb;
10. fb.Byte[0] = 0x9A;
11. fb.Byte[1] = 0xFB;
12. fb.Byte[2] = 0xE7;
13. fb.Byte[3] = 0x3F;
14. printf(“%f\ r\ n”,fb.Float);
15. }

Historical version update notes

V1.3_0628

|

2021/6/28

| Add Human sensitivity explained and fall

sensitivity explained

V1.4_0906| 2021/9/06| Human sensitivity revised from 0-9 to 1-10

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