Example Code for Arduino-Query Module Baud Rate

Hardware Preparation

• DFRduino Leonardo (or similar) x 1
• Capacitive Fingerprint Sensor - UART (FPC Connector) × 1
• DuPont Wires

Software Preparation

• Arduino IDE
• Download and install the ID809 Library. (About how to install the library?)

Wiring Diagram

Sample Code

The module's baud rate is 115200 by default. You can use the following codes to query if you don't know its buad rate (the buad rate will not be restored to the default when the module is power off).

/*!
 * @file queryDeviceBPS.ino
 * @brief Query device baud rate
 * @n Experiment Phenomenon：Query device baud rate, and print from serial port 
 * @copyright  Copyright (c) 2010 DFRobot Co.Ltd (http://www.dfrobot.com)
 * @licence     The MIT License (MIT)
 * @author [Eddard]([email protected])
 * @version  V1.0
 * @date  2020-03-19
 * @get from https://www.dfrobot.com
 * @url https://github.com/DFRobot/DFRobot_ID809
*/
#include <DFRobot_ID809.h>

/*Use software serial when using UNO or NANO*/
#if ((defined ARDUINO_AVR_UNO) || (defined ARDUINO_AVR_NANO))
    #include <SoftwareSerial.h>
    SoftwareSerial Serial1(2, 3);  //RX, TX
    #define FPSerial Serial1
#else
    #define FPSerial Serial1
#endif

DFRobot_ID809 fingerprint;

uint32_t ID809_BPS[5] = {9600, 19200, 38400, 57600, 115200};
uint8_t i = 0;

void setup(){
  /*Init print serial port */
  Serial.begin(9600);
  /*Test module baud rate */
  FPSerial.begin(ID809_BPS[i]);
  Serial.print(".");
  while(fingerprint.begin(FPSerial) == false){
    i++;
    FPSerial.begin(ID809_BPS[i]);
    Serial.print(".");
  }
  Serial.println(" ");
}

void loop(){
  Serial.print("Module baud rate:");
  Serial.println(ID809_BPS[i-1]);
  Serial.println("-----------------------------");
  delay(1000);
}

Result