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IoT Biometric Fingerprint Attendance System using ESP8266

Mamtaz AlamBy Updated:96 Comments7 Mins Read
IOT Biometric Fingerprint Attendance

Overview

In this project IoT Biometric Project, we will learn how to build IoT based Biometric Fingerprint Attendance System using NodeMCU ESP8266 12E, 0.96” OLED Display & R305 Fingerprint Sensor. The ESP8266 Wi-Fi Module will collect the fingerprint data from multiple users and sends it over the internet to a website. The Enrolment of fingerprints is done on the Server using R305 or R307 or any other compatible Fingerprint Sensor and verification is done on the client with the transmission of fingerprint templates over the network.

The website that is coded in PHP has a database and records of attendance. By logging into the website, you can collect all the attendance records of each user including personal details as well as incoming & outgoing timing. The data can also be downloaded and exported to an excel sheet.

IOT Based Biometric Fingerprint Attendance System using NodeMCU

Conventional authentication technologies like RFID tags and authentication cards have a lot of weaknesses, the biometric method of authentication is a prompt replacement for this. Biometrics such as fingerprints, voices and ECG signals are unique human characters that cannot be tampered or replicated. This facilitates real-time system implementations. Biometric Attendance systems are commonly used systems to mark the presence in offices and schools as well as in Biometric Security Lock. This project has a wide application in schools, colleges, business organizations, offices where marking of attendance is required accurately with time. Thus, by using the fingerprint sensor, the system will become more secure for the users.

You can follow the basic level of the same project here: Arduino Fingerprint Attendance System. In case if you want a better fingerprint sensor with small and light weight, you can use GT511C3 fingerprint sensor.


Bill of Materials

The following are the components required to make IoT Based Biometric Fingerprint Attendance System. All the components can be purchased from Amazon. The purchase links are given below.

S.N.Components QuantityPurchase Links
1NodeMCU ESP8266 Board1Amazon | AliExpress
2R305/R307 Fingerprint Sensor1Amazon | AliExpress
30.96" I2C OLED Display1Amazon | AliExpress
4Connecting Wires10Amazon | AliExpress
5Breadboard1Amazon | AliExpress

R305 Fingerprint Scanner Sensor Module

Introduction

This is a finger print sensor module with TTL UART interface for direct connections to microcontroller UART or to PC through MAX232 / USB-Serial adapter. The user can store the finger print data in the module and can configure it in 1:1 or 1: N mode for identifying the person.

Fingerprint Sensor Based Biometric Attendance System

The Fingerprint module can be directly interfaced with any microcontroller as well as Arduino Board. This optical biometric fingerprint reader with great features and can be embedded into a variety of end products like access control systems, attendance systems, safety deposit boxes, car door locking systems.



Features

1. Integrated image collecting and algorithm chip together, ALL-in-One
2. The fingerprint reader can conduct secondary development, can be embedded into a variety of end products
3. Low power consumption, low cost, small size, excellent performance
4. Professional optical technology, precise module manufacturing techniques
5. Good image processing capabilities can successfully capture image up to resolution 500 dpi

Specifications

1. Fingerprint sensor type: Optical
2. Sensor Life: 100 million times
3. Static indicators: 15KVBacklight: bright green
4. Interface: USB1.1/UART(TTL logical level)
5. RS232 communication baud rate: 4800BPS~115200BPS changeable
6. Dimension: 553221.5mm
7. Image Capture Surface 15—18(mm)
8. Verification Speed: 0.3 sec
9. Scanning Speed: 0.5 sec
10. Character file size: 256 bytes
11. Template size: 512 bytes
12. Storage capacity: 250
13. Security level: 5 (1,2,3,4,5(highest))
14. False Acceptance Rate (FAR) :0.0001%
15. False Rejection Rate (FRR): 0.1%
16. Resolution 500 DPI
17. Voltage :3.6-6.0 VDC
18. Working current: Typical 90 mA, Peak 150mA
19. Matching Method: 1: N
20. Operating Environment Temperature: -20 to 45° centigrades

0.96″ I2C OLED Display

This is a 0.96 inch blue OLED display module. The display module can be interfaced with any microcontroller using SPI/IIC protocols. It is having a resolution of 128×64. The package includes display board, display,4 pin male header pre-soldered to board.

I2C OLED Display

OLED (Organic Light-Emitting Diode) is a self light-emitting technology composed of a thin, multi-layered organic film placed between an anode and cathode. In contrast to LCD technology, OLED does not require a backlight. OLED possesses high application potential for virtually all types of displays and is regarded as the ultimate technology for the next generation of flat-panel displays.

Circuit Diagram: IOT Based Biometric Fingerprint Attendance System

Fingerprint Attendance System ESP8266

The above circuit diagram shows how an OLED Display & Fingerprint Sensor is interfaced with NodeMCU ESP8266 12E Board. The I2C pins of OLED Display, i.e SDA & SCL are connected to NodeMCU D2 & D1 pins respectively. Similarly, the fingerprint sensor is connected to UART pins D5 & D6. The fingerprint sensor Tx and Rx wire’s color may vary. In my case, the color is yellow and blue where yellow is Tx and Blue is Rx. So connect it by finding appropriate color wires else the module won’t be detected by NodeMCU.

The R305 fingerprint sensor is supplied with 5V through Vin pins of NodeMCU. In my case, the sensor didn’t work at 3.3V. Similarly, connect OLED Vcc pin to 3.3V of NodeMCU.


Setting Up the Website

Here we can set up a website if you have a website and a server. In case you don’t wanna spend money on website management, then you can use your computer IP as a server to store the data locally in localhost.

First Download and install Xampp from the link here: Download XAMPP

Once the download and installation is completed copy the following folder:Biometricattendance Folder to C:\xampp\htdocs. This is the location of the website in your C drive.

IOT Fingerprint Attendance

The website setting process is a little long which is explained in the video below: You can follow the video to completely set up the website.

Source Code/Program

Below is the source code for IoT Based Biometric Fingerprint Attendance System. The code credit goes to original author of the code: Electronics Tech YouTube Channel

Make Sure to change the wifi username and password from this line below:

Also, change the IP Address if you are using Xampp or change the website server if you are on real website from the line below:


Add the following libraries via library manager or simply by adding the following zip files:
1. OLED GFX Library: Download
2. SSD1306 Library: Download
3. Adafruit Fingerprint Sensor Library: Download


Results

Once the Code is uploaded the NodeMCU will boot up with the Adafruit logo. And then it will try the connection to the wifi. Once it gets Connected it will display Connected. This log can be viewed on Serial Monitor as well as in OLED Display

So now you can start registering the user using the website. The whole process of registration is explained in the video below. You can follow the video for the registration process. The user fingerprint is taken twice and stored in the EEPROM of the Fingerprint Sensor. It is to be noted that only 127 fingerprints can be stored in this R305/R307 module.

So once the fingerprint of multiple users is stored, you can start scanning and registering the attendance. In case the fingerprint is not matched it will display an error message as shown in the figure below.

When a registered user scans his finger for the first time it will display the welcome message.

When a registered user scans his finger for the second time it will display the Good-Bye message.

Finally you can see the entire data of the users on the website as shown below:

For understanding the whole process: how to add, update and remove the users from the database follow the video tutorial below.

Video Tutorial & Explanation

IoT Based Biometric Fingerprint Attendance System with NodeMCU ESP8266
Watch this video on YouTube.

You can also follow the advanced version of the Biometric Attendance System project called as Face Recognition Attendance System project designed using ESP32 Camera Module.

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96 Comments

  1. thor on

    is there any alternative fingerprint sensor w/ module you can suggest if the r305 module is hard to find in our country? can you suggest any suitable fingerprint sensor that can replace your requirement?

    Reply
  2. khairul on

    hai sir..can you help me on connecting the vcc 5v fingerprint to the nodemcu because i tried connect the vcc to the VIN pin but it still cannot detect the sensor. is there any way to make this work?

    Reply
    • Alex Newton on

      This can happen in multiple cases:
      1. Check the tx rx connection
      2. Fingerprint module requires high power, i.e 5V so try connecting its VCC Pin to external 5V,1A power supply.

      Reply
  3. Jorge Garza on

    I have a few questions, i currently want to store the fingerprint template on a DB on sql on my server, as far as i understand this example works great for that function, right?
    Or does this only local store the templates on the sensor memory?

    Reply
    • Alex Newton on

      Hi you can change the database name and password to store it on the server. For demonstration purpose, I used localhost computer location.

      Reply
    • Alex on

      The SSD1306 and SH1106 have a compatibility issue. There is only one small difference between SSD1306 and SH1106: The SH1106 controller has an internal RAM of 132×64 pixels. The SSD1306 only has 128×64 pixels.

      Reply
  7. Parth Srivastava on

    I followed the complete setup of the website but i the website after it adds a fingerprint it keeps on displaying a message-“You cannot add more than 1 id at a time” and this problem persists even after restarting the system.Please help.

    Reply
  8. Parth Srivastava on

    I followed the complete setup process of the website but after registering the first fingerprint when i add the second it keeps on saying’You cannot add more than 1 id at a time’ and this problem persists even after restarting the system.Please help.

    Reply
  12. biometric attendance on

    hello i followed all instructions but when i got the 1st scan of finger print it checked and then locked on..please help.thanks

    Reply
  14. charles on

    You can’t add more than one ID each time…. please help this is the error i encountered while adding user FingerID

    Reply
  15. Garvit Malik on

    Hello SIr,i am using the R-307 Sensor and have used the VCC(5V) supply from the node but it is still not detecting the sensor. perhaps u could tell me the Tx,Rx connections of the R-307 sensor

    Reply
  18. avi on

    The scanning part never takes place on the oled,all is shows is the fingerprint logo.
    It does not scan for the database

    Reply
  19. Dushko on

    I’ve successfully added one user but when i try to add another it’s showing this message: “You can’t add more than one ID each time”. Can you explain me what is the problem.

    Reply
  22. Tripti on

    I followed complete steps, but it is showing that “u cannot add more than one id at a time”, please tell me how to solve this problem

    Reply
  24. Rohit on

    Hey my Node MCU is not detecting the fingerprint sensor, whenever I connect the wire to Vin the sensor blinks once and stops working.

    Reply
  25. Rushi on

    I am trying with different finger for 2nd user but it not taking but i use same finger for different user its taking.. Can you help me?

    Reply
  26. Meet patel on

    Hello, sir instade of led i have use the Lcd With i2c and i have make to changes the code for display but its not esp is not able to commect to the server for sending fingerprint data or for enrollment from server.esp is able to connect to the Internet

    Reply
  28. MUHAMMAD KHAIRUL 'IZUWAN BIN MUHAMAD on

    i got error…..

    Arduino: 1.8.13 (Windows Store 1.8.42.0) (Windows 10), Board: “NodeMCU 1.0 (ESP-12E Module), 80 MHz, Serial, 115200, 4M (3M SPIFFS)”

    In file included from C:\Users\Totoro-an\Documents\Arduino\libraries\Adafruit-GFX-Library-master\Adafruit_GrayOLED.cpp:20:0:

    Multiple libraries were found for “WiFiClient.h”

    C:\Users\Totoro-an\Documents\Arduino\libraries\Adafruit-GFX-Library-master\Adafruit_GrayOLED.h:30:32: fatal error: Adafruit_I2CDevice.h: No such file or directory

    Used: C:\Users\Totoro-an\Documents\ArduinoData\packages\esp8266\hardware\esp8266\2.0.0\libraries\ESP8266WiFi

    #include

    Not used: C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.42.0_x86__mdqgnx93n4wtt\libraries\WiFi

    compilation terminated.

    exit status 1

    Error compiling for board NodeMCU 1.0 (ESP-12E Module).

    This report would have more information with
    “Show verbose output during compilation”
    option enabled in File -> Preferences.

    Reply
  30. Archana on

    Good evening sir,
    Please help me with the pin diagram of r307, it is confusing on net.
    What are the value of these yellow and blue wire of the fingerprint sensor?

    Reply
  31. lava kumar on

    works good when using xampp, but if I replicate the same in my custom website using cpanel , the timeout fingerprint scan sequence doesnot occur. After scanning for login, if I scan again to logout, it is recorded as new line for. login.

    can anyone suggest how to slove it

    Reply
  34. Vishal Meshram on

    my ESP8266 12E, disconnects immediately after it gets connects to Interne through WiFi, showing the following result

    Kindly Guide me further

    Adafruit finger detect test
    Found fingerprint sensor!
    Sensor contains 5 templates
    Waiting for valid finger…
    Connecting to PRANAM
    …………..
    Connected
    IP address: 192.168.1.14

    ————— CUT HERE FOR EXCEPTION DECODER —————

    Exception (29):
    epc1=0x402072d3 epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000010 depc=0x00000000

    stack>>>

    ctx: cont
    sp: 3ffffcd0 end: 3fffffc0 offset: 0190
    3ffffe60: 00000000 00000013 3ffffef0 4020510c
    3ffffe70: 3ffe8a39 3ffffef0 3ffffeb4 40207351
    3ffffe80: 00000000 3ffffef0 3ffffef0 40204855
    3ffffe90: 00000000 000d000f 00000000 3ffeea90
    3ffffea0: 3fffdad0 402049be 00000020 401011bc
    3ffffeb0: 00000000 00000000 00000028 3fff0d98
    3ffffec0: 3fff0d7c 3ffffef0 00000000 40204a0c
    3ffffed0: 3fffdad0 00000000 3fffff80 3ffeea90
    3ffffee0: 3fffdad0 00000000 3ffee78c 40201805
    3ffffef0: 00000000 00000000 3ffee8bd 00000000
    3fffff00: 00010000 de001388 00000000 00000001
    3fffff10: 00000000 00000000 00000001 00000000
    3fffff20: 3fff0994 0031003f 80000000 3fff0d2c
    3fffff30: 0011001f 80000000 00000000 40208286
    3fffff40: 00000000 00000000 00000000 00000000
    3fffff50: ffffffff 002f9d00 00000000 0000000a
    3fffff60: 00000000 3ffeeba0 00000000 00000000
    3fffff70: 3fff0d7c 00000000 0021002f 00000000
    3fffff80: 00000000 000c000f 00000000 40208e6a
    3fffff90: 3fffdad0 00000000 3ffeea7c 40201e2b
    3fffffa0: 3fffdad0 00000000 3ffeea7c 40208308
    3fffffb0: feefeffe feefeffe 3ffe85e8 40101445
    <<<stack<<<

    ————— CUT HERE FOR EXCEPTION DECODER —————

    ets Jan 8 2013,rst cause:2, boot mode:(3,6)

    load 0x4010f000, len 3460, room 16
    tail 4
    chksum 0xcc
    load 0x3fff20b8, len 40, room 4
    tail 4
    chksum 0xc9
    csum 0xc9
    v0004cd50
    ~ld

    Adafruit finger detect test
    Found fingerprint sensor!
    Sensor contains 5 templates
    Waiting for valid finger…
    Connecting to PRANAM
    ……………..

    Reply
  35. Sharcu Lucasan on

    Can i have a question? I use NodeMCU esp8266 V3. And R305 the code runs ok and the ide recognize the module but the problem is my module blink slow and it can’t read fingerprint even the input is already 5V. Can you recommend any solution sir?

    Reply
  37. Prince Joshua on

    Sir I am using Esp32 for this project, whenever I click on add user it doesn’t add a new user but rather it just stays stuck on the logo, pls help me sir it’s really urgent

    Reply
  38. faiza on

    http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP

    Do I have to put something here?

    exit status 1
    call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)

    When i run,it show this

    Reply
  39. Vishal Meshram on

    R307 is not saving templates more than 150, whereas datasheet says it can save 1000 templates. what is the problem,,,

    Reply
  41. Ramkrushna Suresh Shinde on

    Hey faiza…Did you got solution for this error…actually i am stucked in same error..Thanks

    Reply
  44. Assane on

    C:\Users\Assane\Downloads\Biometric-attendance-system-V1.0-master\Biometric-attendance-system-V1.0-master\nodeMCU_Fingerprint\nodeMCU_Fingerprint.ino: In function ‘void SendFingerprintID(int)’:
    nodeMCU_Fingerprint:613:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    613 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\Assane\Downloads\Biometric-attendance-system-V1.0-master\Biometric-attendance-system-V1.0-master\nodeMCU_Fingerprint\nodeMCU_Fingerprint.ino: In function ‘void ChecktoDeleteID()’:
    nodeMCU_Fingerprint:725:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    725 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\Assane\Downloads\Biometric-attendance-system-V1.0-master\Biometric-attendance-system-V1.0-master\nodeMCU_Fingerprint\nodeMCU_Fingerprint.ino: In function ‘void confirmAdding()’:
    nodeMCU_Fingerprint:1003:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    1003 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\Assane\Downloads\Biometric-attendance-system-V1.0-master\Biometric-attendance-system-V1.0-master\nodeMCU_Fingerprint\nodeMCU_Fingerprint.ino: In function ‘void ChecktoAddID()’:
    nodeMCU_Fingerprint:799:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    799 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    Plusieurs bibliothèque trouvées pour “Adafruit_Fingerprint.h”
    Utilisé : C:\Users\Assane\Documents\Arduino\libraries\Adafruit_Fingerprint_Sensor_Library
    Non utilisé : C:\Users\Assane\Documents\Arduino\libraries\Adafruit-Fingerprint-Sensor-Library-master
    exit status 1
    call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)

    help me

    Reply
  45. Assane on

    http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP

    Do I have to put something here?

    exit status 1
    call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)

    When i run,it show this

    Reply
  47. Ganesh on

    C:\Users\ASUS\Documents\Arduino\sketch_apr27a\sketch_apr27a.ino: In function ‘void SendFingerprintID(int)’:
    sketch_apr27a:602:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    602 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\ASUS\Documents\Arduino\sketch_apr27a\sketch_apr27a.ino: In function ‘void ChecktoDeleteID()’:
    sketch_apr27a:714:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    714 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\ASUS\Documents\Arduino\sketch_apr27a\sketch_apr27a.ino: In function ‘void confirmAdding()’:
    sketch_apr27a:992:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    992 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    C:\Users\ASUS\Documents\Arduino\sketch_apr27a\sketch_apr27a.ino: In function ‘void ChecktoAddID()’:
    sketch_apr27a:788:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    788 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    Multiple libraries were found for “WiFiClient.h”
    Used: C:\Users\ASUS\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\libraries\ESP8266WiFi
    Not used: C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.57.0_x86__mdqgnx93n4wtt\libraries\WiFi
    exit status 1
    call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)

    I got This error, pls help sir.

    Reply
  50. roobenprakaash on

    hi sir im using your code with follow your steps but got error… why sir
    error message (‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    )

    Reply
  51. roobenprakaash on

    hi sir im using your code with follow your steps but got error… why sir
    error message (‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    )

    Reply
  52. Rooben Prakaash Soomu on

    C:\Users\User\Desktop\Final_Year_project\Final_Year_project.ino: In function ‘void SendFingerprintID(int)’:
    Final_Year_project:605:13: error: call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)
    605 | http.begin(link); //initiate HTTP request, put your Website URL or Your Computer IP
    | ~~~~~~~~~~^~~~~~
    Multiple libraries were found for “WiFiClient.h”
    Used: C:\Users\User\Documents\ArduinoData\packages\esp8266\hardware\esp8266\3.0.2\libraries\ESP8266WiFi
    Not used: C:\Program Files\WindowsApps\ArduinoLLC.ArduinoIDE_1.8.57.0_x86__mdqgnx93n4wtt\libraries\WiFi
    exit status 1
    call to ‘HTTPClient::begin’ declared with attribute error: obsolete API, use ::begin(WiFiClient, url)

    Why sir its showing like this…. sir can solve my problem

    Reply
  53. Venkat on

    Hi sir.. i have some doubts about this project
    1. Can I get the circuit diagram of entire setup
    2. from where we have to give the power supply to the setup

    Reply
  56. Pranneth on

    sir I had given ssid,password correctly but also it isn’t connecting to wifi.Instead its just showing connecting to .

    Reply
  57. Praneeth on

    can you help me out
    sir I had given ssid,password correctly but also it isn’t connecting to wifi.Instead its just showing connecting to .

    Reply
    • kait-developer on

      if you getting error
      fix your esp8266 version
      downgrade to 2.7.1 version
      xampp version , all version
      for me i modified send whatsapp with node.js
      here my code
      String serverPath = serverName + “?tujuan=” + NoId + “&pesan=Informasi+Kehadiran+Siswa%0ASMK+Harapan+Mulya+Brangsong%0A%0ANama:+” + nama_tampil + “%0AKelas:%0AKeterangan:+Siswa+Sudah+Pulang%0A%0A_Terima+kasih+atas+perhatianya_”;
      http_a.begin(client, serverPath.c_str());
      int httpResponseCode = http_a.GET();

      Reply
  62. Heyner Moncada on

    Hi, Can I save the fingerprint template on a Database field and then compare it when by searching on the database?

    Reply
  65. Abnet gobezay on

    Bro i can’t connect the data base and finger print can u tell me pls when i add user there is no display on data base

    Reply
  69. kay on

    Hi, thanks for the tutorial. How can i use the solution to achieve student attendance as stated below.
    1. The fingerprint of the student is compared with the one stored in database and if it matches then attendance is marked for that particular student.
    2. The system also generates a brief report of attendance from the database according to subject-wise or date-wise as required.
    3. A defaulter list can be generated through system

    Reply
  70. Saad Inam on

    Hello, I’m using ESP 32S having 19 pins and your ESP module have 15 pins. So please guide us how I connect my fingerprint sensor and OLED display with my wifi module Your Esp Module have D number of pins and my ESP module have P number of pins its very confusing to make complete circuit.

    Reply
    • Deb ghosh on

      now it’s year 2024…you have to create some own logic to get solution for this type of error. if you are using arduino ide… this error will show if you not “return” anything from this function “confirmAdding();”. actually (“control reaches end of non-void function [-Werror=return-type]” ) this is not an error.this is a warning.. now this type of warning is blocking like a error…

      all the matters of versions matching…for every library….then hurray!!!

      Reply
    • Hock soon on

      Hi kumi, have you solve this issues as I have the same issues after I try to upload. Thank in advance if you can help me

      Reply
  79. Hardik Patel on

    In serial monitor show ‘ fingerprint sensor not found’. Also i check the fingerprint sensor chek code sensor is perfect working, how to solve problems.

    Reply

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