Example Code for Arduino-Registering Face & Palm Print

Hardware Preparation

• DFRduino UNO R3 x 1
• Gravity: IO Expansion Shield for Arduino V7.1 x 1
• FP02 Offline AI Vision Recognition Sensor (Face & Palm Vein) x 1
• MX1.25mm to 2.54mm DuPont cable x1

Software Preparation

• Arduino IDE
• Download DFRobot_Biometric library

Wiring Diagram

Other Preparation Work

When registering a face or palm print, the AI ​​vision sensor needs to be fixed in place, and attention should be paid to the recognition distance: 20-90cm for faces and 15-20cm for vein and palm prints.

Instruction 1: Register a face user. The same face can only be registered once.
Instruction 2: Register a vein and palm print user. The same palm print can be registered repeatedly, but only once.

Sample Code

/*!
 * @file enrollUser.ino
 * @brief Example of face or palm user enrollment for SEN0736 and SEN0737
 * @details This example performs user enrollment every time you input the command:1 (enroll face),2 (enroll palm)
 * @n and prints the enrollment result through the serial port
 * @n Enrollment should work normally as long as the connection is correct
 * @copyright Copyright (c) 2026 DFRobot Co.Ltd (http://www.dfrobot.com)
 * @license The MIT License (MIT)
 * @author [Olive]([email protected])
 * @version V1.0.0
 * @date 2026-06-02
 * @url https://github.com/DFRobot/DFRobot_Biometric
 */

#include "DFRobot_Biometric.h"

/* -----------------------------------------------------------------------------------------------------
  *    board   |             MCU                |   Leonardo/Mega2560/M0  |   ESP8266  |     ESP32     |
  *     VCC    |            3.3V/5V             |          VCC            |    VCC     |      VCC      |
  *     GND    |              GND               |          GND            |    GND     |      GND      |
  *     RX     |              TX                |      Serial1 TX1        |    5/D6    |  Serial2 TX1  |
  *     TX     |              RX                |      Serial1 RX1        |    4/D7    |  Serial2 RX1  |
  * ----------------------------------------------------------------------------------------------------*/
/* Baud rate cannot be changed , it is 115200 */

#if defined(ESP8266) || defined(ARDUINO_AVR_UNO)
#define SOFT_RX_PIN 4
#define SOFT_TX_PIN 5
#include <SoftwareSerial.h>
SoftwareSerial ModuleSerial(SOFT_RX_PIN, SOFT_TX_PIN);
#elif defined(ESP32)
#define RX_PIN       16
#define TX_PIN       17
#define ModuleSerial Serial2
#else
#define ModuleSerial Serial1
#endif

DFRobot_Biometric face(ModuleSerial);

void setup()
{
#if defined(ESP32)
  ModuleSerial.begin(115200, SERIAL_8N1, RX_PIN, TX_PIN);
#else
  ModuleSerial.begin(115200);
#endif

  Serial.begin(115200);                   //Start serial 1, for information printing
  delay(2000);                            //Wait for module to start
  while (face.checkState() == false) {    //Determine whether the module is ready
    Serial.println("Module not ready!");
    delay(200);
  }
  Serial.println("Module ready!");

  Serial.println("----------------------------------------------------");
  Serial.println("Enter the command below through the serial port:");
  Serial.println("1     # enroll face user");
  Serial.println("2     # enroll palm user");
  Serial.println("----------------------------------------------------");
}

uint16_t                       id;
char                           faceName[]   = "face";
char                           palmName[]   = "palm";
char                           fullName[20] = { 0 };
DFRobot_Biometric::eIsAdmin_t  userclass    = face.eRoleNormal;
DFRobot_Biometric::eUserKind_t userKind     = face.eFaceUser;
uint16_t                       i = 1, j = 1;
void                           loop()
{
  char   data[11] = { 0 };
  int8_t result   = 0;

  while (!Serial.available()) {
    ;
  }
  String input = Serial.readStringUntil('\n');
  input.trim();
  input.toCharArray(data, 10);
  Serial.println("-----------------------------------------------------------------------------------------------");
  if (strcmp(data, "1") == 0 || strcmp(data, "2") == 0) {
    if (strcmp(data, "1") == 0) {
      Serial.println("Start face enrollment. Please keep your face directly facing the camera, 30cm~60cm away");
      snprintf(fullName, sizeof(fullName), "%s%d", faceName, i);
      userKind = face.eFaceUser;
      result   = face.enrollUser(userKind, fullName, &id, userclass);
    } else {
      Serial.println("Start palm enrollment. Please keep your palm directly facing the camera, 15cm~20cm away");
      snprintf(fullName, sizeof(fullName), "%s%d", palmName, j);
      userKind = face.ePalmUser;
      result   = face.enrollUser(userKind, fullName, &id, userclass);
    }
    //Determine the execution result
    if (result == 1) {
      if (strcmp(data, "1") == 0) {
        Serial.println("Face enrollment successful!");
      } else {
        Serial.println("Palm enrollment successful!");
      }
      Serial.print("the user id is:");
      Serial.println(id);
      Serial.print("the user name is:");
      Serial.println(fullName);
      Serial.print("the user kind is:");
      if (userKind == face.eFaceUser) {
        Serial.println("face user");
      } else if (userKind == face.ePalmUser) {
        Serial.println("palm user");
      }
      Serial.print("the userClass is:");
      if (userclass == face.eRoleNormal) {
        Serial.println("Normal user");
      } else if (userclass == face.eRoleAdmin) {
        Serial.println("Administrator");
      }
      if (strcmp(data, "1") == 0) {
        i++;
      } else {
        j++;
      }
    } else if (result == 2) {
      Serial.println("User already exists");
    } else if (result == 3) {
      Serial.println("Enrollment timeout");
    } else if (result == NO_ACK) {
      Serial.println("No response from module");
    } else if (result == ERROR) {
      Serial.println("Parameter range error");
    }
  } else {
    Serial.println("Error command!");
  }
  Serial.println("-----------------------------------------------------------------------------------------------");
  Serial.println("");
  Serial.println("please input next command:");
  Serial.println("");
  delay(2000);
}

Result

Each registration takes 10 seconds. After successful registration, the corresponding information will be printed. If the registration times out, you can re-register by entering the command. IDs 1-500 are for faces, and IDs 501-800 are for veins and palm prints.