Example Code for Arduino-Read Detection Distance

Hardware Preparation

• DFRduino UNO R3 with IO Expansion Shield and USB Cable A-B (or similar) x 1
• 24GHz Human Presence Sensing Module × 1
• Connector × 1

Software Preparation

• Arduino IDE

Wiring Diagram

Sample Code

#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); //定义软串口，3号端口为TX，2号端口为RX，

size_t readN(uint8_t *buf, size_t len);

bool recdData(uint8_t *buf);

uint8_t Cache[23] = {0};    //缓存

void setup()
{
  Serial.begin(115200);      //串口波特率
  mySerial.begin(57600); //软串口
  //Serial1.begin(256000);
}

void loop()
{
  recdData(Cache);
}

size_t readN(uint8_t *buf, size_t len)
{
  size_t offset = 0, left = len;
  int16_t Tineout = 1500;
  uint8_t  *buffer = buf;
  long curr = millis();
  while (left) {
    if (Serial1.available()) {
      //buffer[offset] = Serial1.read();
	  buffer[offset] = Serial.read();
      offset++;
      left--;
    }
    if (millis() - curr > Tineout) {
      break;
    }
  }
  return offset;
}

bool recdData(uint8_t *buf)
{
  int16_t Tineout = 50000;
  long curr = millis();
  uint8_t ch;
  bool ret = false;
  const char *P;
  while (!ret) {
    if (millis() - curr > Tineout) {
      break;
    }
    if (readN(&ch, 1) == 1) {
      if (ch == 0xF4) {
        buf[0] = ch;
        if (readN(&ch, 1) == 1) {
          if (ch == 0xF3) {
            buf[1] = ch;
            if (readN(&ch, 1) == 1) {
              if (ch == 0xF2) {
                buf[2] = ch;
                if (readN(&ch, 1) == 1) {
                  if (ch == 0xF1) {
                    buf[3] = ch;
                      if (readN(&buf[4], 19) == 19) {
//                        printdf(buf, 23); //打印原始数据
                        uint16_t Adistance = buf[10] << 8 | buf[9];
                        uint16_t Sdistance = buf[13] << 8 | buf[12];
                        uint16_t Distance = buf[16] << 8 | buf[15];
                        switch (buf[8]) {
                          case 0x00 : Serial.println("检测状态:无人"); break;
                          case 0x01 : Serial.println("检测状态:运动"); break;
                          case 0x02 : Serial.println("检测状态:静止"); break;
                          case 0x03 : Serial.println("检测状态:运动&静止目标"); break;
                        }
//                        Serial.print("运动目标能量值:");
//                        Serial.println(buf[11]);
//                        Serial.print("静止目标能量值:");
//                        Serial.println(buf[14]);
//                        Serial.print("运动目标距离CM:");
//                        Serial.println(Adistance);
//                        Serial.print("静止目标距离CM:");
//                        Serial.println(Sdistance);
                        Serial.print("探测距离CM:");
                        Serial.println(Distance);
                        break;
                      }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
  return ret;
}
void printdf(uint8_t *buf, int len)
{
  for (int i = 0; i < len; i++) {
    if (buf[i] < 0x10) {
      Serial.print("0");
    }

    Serial.print(buf[i], HEX);
    Serial.print(" ");
  }
  Serial.println();
}

Result

The module only outputs the target distance value of the moving state, and the distance value of the non-moving state is 0.For details, please refer to the serial communication protocol description.