Example Code for Arduino-Fingerprint Matching

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

Collect the fingerprint image and compare it with the fingerprints in the fingerprint library. If they matches, the green light will be on and the ID number will be printed, otherwise, the red light will be on and the matching failure will be prompted.

/*!
 * @file fingerprintMatching.ino
 * @brief Collect fingerprint and compare it with fingerprints in fingerprint library
 * @n Experiment Phenomenon：capture fingerprint image and compare it with all fingerprints in the fingerprint library,
                If matched successfully, light up green LED and print ID number. Return 0 when failed.
 * @copyright  Copyright (c) 2010 DFRobot Co.Ltd (https://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;
//String desc;   //Error code information, enabling this function will consume much memory

void setup(){
  /*Initialize serial port for printing*/
  Serial.begin(9600);
  /*Initialize FPSerial*/
  FPSerial.begin(115200);
  /*Use FPSerial as communication serial port of module*/
  fingerprint.begin(FPSerial);
  /*Wait for Serial to open*/
  while(!Serial);
  /*Test whether device can communicate properly with mainboard,
    Return true or false
    */
  while(fingerprint.isConnected() == false){
    Serial.println("Communication with device failed, please check connection");
    /*Get error code information*/
    //desc = fingerprint.getErrorDescription();
    //Serial.println(desc);
    delay(1000);
  }
}

void loop(){
  uint8_t ret = 0;
  /*Set fingerprint LED ring mode, color, and number of blinks,
    Can be set as follows：
    Parameter 1:<LEDMode>
    eBreathing   eFastBlink   eKeepsOn    eNormalClose
    eFadeIn      eFadeOut     eSlowBlink   
    Parameter 2:<LEDColor>
    eLEDGreen  eLEDRed      eLEDYellow   eLEDBlue
    eLEDCyan   eLEDMagenta  eLEDWhite
    Parameter 3:<number of blinks> 0 represents blinking all the time,
    This parameter will only be valid in mode eBreathing, eFastBlink, eSlowBlink
   */
  fingerprint.ctrlLED(/*LEDMode = */fingerprint.eBreathing, /*LEDColor = */fingerprint.eLEDBlue, /*blinkCount = */0);
  Serial.println("Please press down your finger");
  /*Capture fingerprint image, Disable the collection timeout function 
    If succeed return 0, otherwise return ERR_ID809
   */
  if((fingerprint.collectionFingerprint(/*timeout=*/0)) != ERR_ID809){
    /*Set fingerprint LED ring to quick blink in yellow 3 times*/
    fingerprint.ctrlLED(/*LEDMode = */fingerprint.eFastBlink, /*LEDColor = */fingerprint.eLEDYellow, /*blinkCount = */3);
    Serial.println("Capturing succeeds");
    Serial.println("Please release your finger");
    /*Wait for finger to release
      Return 1 when finger is detected, otherwise return 0 
     */
    while(fingerprint.detectFinger());
    /*Compare the captured fingerprint with all the fingerprints in the fingerprint library,
      Return fingerprint ID(1-80) if succeed, return 0 when failed
     */
    ret = fingerprint.search();
    /*Compare the captured fingerprint with a fingerprint of specific ID
      Return fingerprint ID(1-80) if succeed, return 0 when failed
     */
    //ret = fingerprint.verify(/*Fingerprint ID = */1);  
    if(ret != 0){
      /*Set fingerprint LED ring to always ON in green*/
      fingerprint.ctrlLED(/*LEDMode = */fingerprint.eKeepsOn, /*LEDColor = */fingerprint.eLEDGreen, /*blinkCount = */0);
      Serial.print("Matching succeeds, ID=");
      Serial.println(ret);
    }else{
      /*Set fingerprint LED ring to always ON in red*/
      fingerprint.ctrlLED(/*LEDMode = */fingerprint.eKeepsOn, /*LEDColor = */fingerprint.eLEDRed, /*blinkCount = */0);
      Serial.println("Matching fails");
    }
  }else{
    Serial.println("Capturing fails");
    /*Get error code information*/
    //desc = fingerprint.getErrorDescription();
    //Serial.println(desc);
  }
  Serial.println("-----------------------------");
  delay(1000);
}

Result