Example Code for Arduino-Distance Reading

Hardware Preparation

• TFmini-i LiDAR x1
• DFRduino UNO R3 x1
• RS485 Shield for Arduino x1

Software Preparation

• Arduino IDE

Wiring Diagram

Other Preparation Work

Turn the switch of the expansion board to the OFF first, burn codes into the board, then turn it to the ON. Select the serial port baud rate 115200.

Do not mix UART cable with RS485 wire, otherwise it will cause damage to LiDAR MCU.

Sample Code

uint8_t Com[8] = {0x01, 0x03, 0x00, 0x00, 0x00, 0x01, 0x84, 0x0a};
void setup()
{
  Serial.begin(115200);    //Initialize the serial ports
}
void loop()
{
  int Distance =readDistance();
  Serial.print("Distance = ");
  Serial.print(Distance);
  Serial.println(" CM");
  delay(500);
}

int readDistance(void)
{
  uint8_t Data[10] = {0};
  uint8_t ch = 0;
  bool flag = 1;
  int Distance = 0;
  while (flag) {
    delay(100);
    Serial.write(Com, 8);
    delay(10);
    if (readN(&ch, 1) == 1) {
      if (ch == 0x01) {
        Data[0] = ch;
        if (readN(&ch, 1) == 1) {
          if (ch == 0x03) {
            Data[1] = ch;
            if (readN(&ch, 1) == 1) {
              if (ch == 0x02) {
                Data[2] = ch;
                if (readN(&Data[3], 4) == 4) {
                  if (CRC16_2(Data, 5) == (Data[5] * 256 + Data[6])) {
                    Distance = Data[3] * 256 + Data[4];
                    //Serial.println(Distance);
                    flag = 0;
                  }
                }
              }
            }
          }
        }
      }
    }
    Serial.flush();

  }
  return Distance;
}

uint8_t readN(uint8_t *buf, size_t len)
{
  size_t offset = 0, left = len;
  int16_t Tineout = 500;
  uint8_t  *buffer = buf;
  long curr = millis();
  while (left) {
    if (Serial.available()) {
      buffer[offset] = Serial.read();
      offset++;
      left--;
    }
    if (millis() - curr > Tineout) {
      break;
    }
  }
  return offset;
}

unsigned int CRC16_2(unsigned char *buf, int len)
{
  unsigned int crc = 0xFFFF;
  for (int pos = 0; pos < len; pos++)
  {
    crc ^= (unsigned int)buf[pos];
    for (int i = 8; i != 0; i--)
    {
      if ((crc & 0x0001) != 0)
      {
        crc >>= 1;
        crc ^= 0xA001;
      }
      else
      {
        crc >>= 1;
      }
    }
  }

  crc = ((crc & 0x00ff) << 8) | ((crc & 0xff00) >> 8);
  return crc;
}

Result

Print the collected distance value.