Introduction

This 24GHz millimeter-wave radar sensor employs FMCW, CW multi-mode modulation and separate transmitter and receiver antenna structure.
In working, the sensor first emits FMCW and CW radio waves to the sensing area. Next, the radio waves, reflected by all targets which are in moving, micro-moving, or extremely weak moving state in the area, are converted into electrical signals by the millimeter-wave MMIC circuit in the sensor system. After that, these signals will be sent to the processor and processed through the related signal and data algorithms. Then, the target information can be solved out.
The millimeter-wave radar can sense the human presence, stationary and moving people within the detection area. Moreover, it can even detect static or stationary human presence such as a sleeping person. There are two ways provided to output detection result: serial port and I/O port switch quantity. Besides that, the sensor module features strong sensing reliability, high sensitivity, small size, easy to be used or embedded in applications.

Features

Specification

Board Overview

The interface definition and function description of this millimeter wave are shown in Table 1.

Num Label Description
1 UART Tx Sensor UART Transmiting
2 UART Rx Sensor UART Receiving
3 GPIO1 Universal Input and Output
4 GPIO2 Universal Input and Output(By default, it outputs high when people presence detected, otherwise, output low)
5 GND Ground
6 VCC Power +
7 NC Reserved, left floating
8 NC Reserved, left floating

The two I/O ports can be used for level trigger input and output applications; The 1 UART port can used to configure input and sense result.

Installtion

The millimeter wave human sensor is strict on the installation method, improper installation will affect the performance and function of the sensor. Commonly-used installation methods for modules include top installation, bottom installation, horizontal installation and downward tilt installation.

  1. Top installation

top

  1. Bottom installation

bottom

  1. Horizontal installation

horizontal

Instructions

The module adopts serial communication protocol and uses ASCII code string as command interation and data interaction.

Output Information Configuration

Description: The default configuration of the sensor is to output the sensing results only in ASCII code string format, and modification is not supported temporarily.

Human body induction result output: ASCII code string format

Description:

Response: $JYBSS,par1,par2,par3,par4*

Parameter Term Description
par1 Induction result:
0: No one
1: People presence detected(stationary or moving)
par2 Placeholder parameter:
reserved, replace with spaces
par3 Placeholder:
reserved, replace with spaces
par4 Placeholder:
reserved, replace with spaces
Example Command
People presence detected (moving or stationary) $JYBSS,1, , , *
No one detected $JYBSS,0, , , *

Sensor Detection Area Configuration

Description:

Command: detRangeCfg par1 parA_s parA_e parB_s parB_e parC_s parC_e parD_s parD_e

Parameter Term Description
par1 Retained, constant -1
parA_s
parA_e
The 1st segment of the sensing area configuration value:
parA_s: the starting value index of the sensing area distance(≥0)
parA_e: the ending value index of the sensing area distance
parB_s
parB_e
The 2nd segment of the sensing area configuration value (the index must start after the 1st segment sensing area configuration index):
parB_s: the starting value index of the sensing area distance
parB_e: the ending value index of the sensing area distance
parC_s
parC_e
The 3rd segment of the sensing area configuration value (the index must start after the 2nd segment sensing area configuration index):
parC_s: the starting value index of the sensing area distance
parC_e: the ending value index of the sensing area distance
parD_s
parD_e
The 4th segment of the sensing area configuration value (the index must start after the 3rd segment sensing area configuration index):
parD_s: the starting value index of the sensing area distance
parD_e: the ending value index of the sensing area distance(≤127)

Note: Multiply the start or end value index of the sensing area distance by 15cm, it represents the start or end distance value.

Response Description
Done The command was executed successfully
Error Command execution failed
Example Command
(Default configuration) Sensing distance: "0m to 3m"
(0m=0 * 0.15cm, 3m=20 * 0.15cm)
detRangeCfg -1 0 20
Sensing distance: "1.5m to 3m"
(1.5m=10 * 0.15cm, 3m=20 * 0.15cm)
detRangeCfg -1 10 20
Sensing distance: "1.5m to 3m" "7.5m to 12m"
(1.5m=10 * 0.15cm, 3m=20*0.15cm)
(7.5m=50 * 0.15cm, 12m=80 * 0.15cm)
detRangeCfg -1 10 20 50 80
Sensing distance: "1.5m to 3m" "7.5m to 12m" "13.5m to 15m"
(1.5m=10 * 0.15cm, 3m=20 * 0.15cm)
(7.5m=50 * 0.15cm, 12m=80 * 0.15cm)
(13.5m=90 * 0.15cm, 15m=100 * 0.15cm)
detRangeCfg -1 10 20 50 80 90 100
Sensing distance: "1.5m to 3m" "7.5m to 12m" "13.5m to 15m" "15.75m to 16.5m"
(1.5m=10 * 0.15cm, 3m=20 * 0.15cm)
(7.5m=50 * 0.15cm, 12m=80 * 0.15cm)
(13.5m=90 * 0.15cm, 15m=100 * 0.15cm)
(15.75m=105 * 0.15cm, 16.5m=110 * 0.15cm)
detRangeCfg -1 10 20 50 80 90 100 105 110

Sensor Output Delay Configuration

Description: configure, when the sensor detects a target, the delay time for the output of the sensing result; after the target disappears, the delay time for the output of the sensing result. By default, when a target detected, the delayed output time is 2.5s; after the target disappears, the delayed output time is 10s.

Command: outputLatency par1 par2 par3

Parameter Term Description
par1 Retained, constant -1
par2 When the target is detected, the delay time for output of sensing results:
Value range: 0~65535, unit: 25ms
par3 After the target disappears, the delay time for output of sensing results:
Value range: 0~65535, unit: 25ms
Response Description
Done The command was executed successfully
Error Command execution failed
Example Command
(Default configuration) The target is detected, the delay time is 2.5 seconds. The target disappears, the delay time is 10 seconds. outputLatency -1 100 400
The target is detected, the delay time is 5 seconds. The target disappears, the delay time is 20 seconds. outputLatency -1 200 800

Sensor Start-up Mode Configuration

Description: Configure the sensor to start running immediately after power-on or wait for the start command after power-on. The former is set by default.

Command: sensorCfgStart par1

Parameter Term Description
par1 Enable the sensor to start running immediately after power-on:
0: Prohibit the sensor to start running immediately after power-on. The sensorStart command is required to start running (default value)
1: Enable the sensor to start running immediately after power-on. No sensorStart command is required to start running
Response Description
Done The command was executed successfully
Error Command execution failed
Example Example
Prohibit the sensor to start running immediately after power on sensorCfgStart 0
(Default configuration) Enable the sensor to start running immediately after power on sensorCfgStart 1

Sensor Start Control

Description:

**- When the sensor is in an unstarted state and there are no set parameters to be saved, start the sensor to run.

Command: sensorStart

Parameter Term Description
Null No parameters
Response Description
Done The command was executed successfully
Error Command execution failed

Sensor Reset Control

Description: Reset the sensor by software

Command: resetSystem

Parameter Term Description
Null No parameters
Response Description
Error Command execution failed
No response string After the command is executed successfully, the sensor will be reset directly, so there is no response string

Sensor Stop Control

Description: Stop the sensor when it is running.

Commands: sensorStop

Parameter Term Description
Null No parameter
Response Description
Done The command was executed successfully
Error Command execution failed, the sensor is not in
operating status

Configuration Save Parameter

Description: When the sensor parameters are reconfigured through the UART and have not been saved, this command saves the new configuration parameters to the sensor Flash

Command: saveCfg par1 par2 par3 par4

Parameter Term Description
par1 Fixed value: 0x45670123
par2 Fixed value: 0xCDEF89AB
par3 Fixed value: 0x956128C6
par4 Fixed value: 0xDF54AC89
Response Description
Done The command was executed successfully
Error Command execution failed (If there are no parameters to save, the command will fail to execute)

Save the configuration parameters to the non-power-loss memory unit, command: saveCfg 0x45670123 0xCDEF89AB 0x956128C6 0xDF54AC89

Factory reset

Description: Restore the current configuration parameter value of the sensor to the factory default value.

Command: factoryReset par1 par2 par3 par4

Parameter Term Description
par1 Fixed value: 0x45670123
par2 Fixed value: 0xCDEF89AB
par3 Fixed value: 0x956128C6
par4 Fixed value: 0xDF54AC89
Response Description
Done The command was executed successfully
Error Command execution failed

Restore configuration parameters to factory default values, command: factoryReset 0x45670123 0xCDEF89AB 0x956128C6 0xDF54AC89

Tutorial for Arduino

Requirements

API Function List

/**
      @brief Constructor 
      @param Stream  Software serial port interface 
    */
    DFRobot_mmWave_Radar(Stream *s);

    /**
      @brief  Configure sensor detection area  
      @param parA_s The sensing area distance starting value of the first segment, unit: m  
      @param parA_e The sensing area distance ending value of the first segment, unit: m(Must be greater than the starting value of the current sensing area)
    */
    void DetRangeCfg(float parA_s, float parA_e);


    /**
      @brief  Configure sensor detection area 
      @param parA_s The sensing area distance starting value of the first segment, unit: m
      @param parA_e The sensing area distance ending value of the first segment, unit: m(Must greater than the starting value of the current sensing area)
      @param parB_s The sensing area distance starting value of the second segment, unit: m(Must be greater than the ending value of the previous segment sensing area) 
      @param parB_e The sensing area ending value of the second segment, unit: m(Must be greater than the starting value of the current sensing area)
    */
    void DetRangeCfg(float parA_s, float parA_e, float parB_s, float parB_e);


    /**
      @brief  Configure sensor detection area 
      @param parA_s The sensing area distance starting value of the first segment, unit: m
      @param parA_e The sensing area distance ending value of the first segment, unit: m (Must be greater than the starting value of the current sensing area)
      @param parB_s The sensing area distance starting value of the second segment, unit: m(Must be greater than the ending value of the previous segment sensing area)
      @param parB_e The sensing area distance ending value of the second segment, unit: m(Must be greater than the starting value of the current sensing area)
      @param parC_s The sensing area distance starting value of the third segment, unit: m(Must be greater than the ending value of the previous segment sensing area)
      @param parC_e The sensing area distance ending value of the third segment, unit: m(Must be greaer than the starting value of the current sensing area)
    */
    void DetRangeCfg(float parA_s, float parA_e, float parB_s, float parB_e, float parC_s, float parC_e);


    /**
      @brief  Configure sensor detection area 
      @param parA_s The sensing area distance starting value of the first segment, unit: m 
      @param parA_e The sensing area distance ending value of the first segment, unit: m(Must be greater than the starting value of the current sensing area)
      @param parB_s The sensing area distance starting value of the second segment, unit: m(Must be greatet than the ending value of the previous segment sensing area)
      @param parB_e The sensing area distance ending value of the second segment, unit: m(Must be greater than the starting value of the current sensing area)
      @param parC_s The sensing area distance starting value of the third segment, unit: m(Must be greater than the ending value of the previous segment sensing area)
      @param parC_e The sensing area distance ending value of the third segment, unit: m(Must be greater than the starting value of the current sensing area)
      @param parD_s The sensing area distance starting value of the fourth segment, unit: m(Must be greater than the ending value of the previous segment sensing area)
      @param parD_e The sensing area ditance ending value of the fourth segment, unit: m(Must be greater than the starting value of the current sensin area)
    */
    void DetRangeCfg(float parA_s, float parA_e, float parB_s, float parB_e, float parC_s, float parC_e, float parD_s, float parD_e);


    /**
      @brief  Read whether there is people or object moving in the sensing area
      @return  Returning true means that there is people or animal moving in the detection range; false means the opposite
    */
    bool readPresenceDetection(void);


    /**
      @brief  Configure sensor output delay time 
      @param par1 When a target detected, delay the output time of sensing result, range:0~1638.375, unit: s 
      @param par2 When the target disappears, delay the output time of sensing result, range: 0~1638.375, unit: s
    */
    void OutputLatency(float par1, float par2);


    /**
      @brief  Restore the sensor current configuration to the factory settings. 
    */
    void factoryReset(void);

Connection Diagram

Connection

mmWave Radar Arduino Uno
VCC 5V
GND GND
RX D2
TX D3

Copy the following code to your Arduino IDE and upload it.

Sample Code

/*!
   @file DFRobot_mmWave_Radar.ino
   @ Read whether there is people or object moving in the detection range of the sensor. 
   @ The sensor detection range and output delay time can be configured. Also you can restore the sensor to factory default settings. 
   @n Experimental phenomenon: When the sensor starts successfully, 0 or 1 will be printed on the serial monitor. 
   @ 0 means that there is no human or object moving in sensing area, 1 means the oppposite. 
   @copyright   Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
   @licence     The MIT License (MIT)
   @author [huyujie](yujie.hu@dfrobot.com)
   @version  V1.0
   @date  2020-3-25
   @https://github.com/DFRobot
*/


#include <SoftwareSerial.h>

#include "DFRobot_mmWave_Radar.h"

SoftwareSerial mySerial(3, 2);
DFRobot_mmWave_Radar sensor(&mySerial);

int ledPin = 13;

void setup()
{
  Serial.begin(115200);
  mySerial.begin(115200);
  pinMode(ledPin, OUTPUT);

  sensor.factoryReset();    //Restore to the factory settings 
  sensor.DetRangeCfg(0, 9);    //The detection range is as far as 9m
  sensor.OutputLatency(0, 0);
}

void loop()
{
  int val = sensor.readPresenceDetection();
  digitalWrite(ledPin, val);
  Serial.println(val);
}

Expected Results

Result

FAQ

For any questions, advice or cool ideas to share, please visit the DFRobot Forum.

More Documents

DFshopping_car1.png Get mmWave Radar-Human Presence Detection from DFRobot Store or DFRobot Distributor.

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