About: Hello world! I make simple & Advanced projects for people who want to learn programming and electronics. Most of my Instructables are about arduino and the wide range of sensors you can use with it. I ma...

Hello world! Today i made a RFID door lock. The lamp acts as a Electric door lock because i don't have a electrical lock, you simply add the door lock to the relay instead of the lamp. Check out the link for the Schematic code & Parts list. I could not find much about the module, i have the RFID-RC522 in blue color, so this might be useful for the ones who have the same problem as me because the red one has the pins different... i only found wrong schematics.. SO here is the right code & schematic.. it works fine to!

Step 1: Parts List, Schematic & Code.

Simply wire it up like the schematic, upload the code and it should work.

There is a button to clear the database. How this works is simple, Just hold the button and reset arduino. Hold it for 6 second and it will clear all cards added. After that you need to add the new master card and key cards.

the video should explain enough.

You can uncomment this line below (line 68) in the code it will increase reading distance : mfrc522.PCD_SetAntennaGain(mfrc522.RxGain_max);

Parts list.

  1. Arduino uno, I used the RobotDyn Uno.
  2. RFID RC522 - Blue colored version.
  3. 1 channel Relay KY-019
  4. KY-004 Button module. (to clear the database)
  5. Jumper wires set. MM/FF/MF.
  6. Electrical door lock, (Optional, Not needed to test the code.)
  7. Mini Bread Board (Optional, i used it so the RFID module stands vertical)

Good luck!

2 People Made This Project!


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20 Discussions

how can i add a solenoid lock to this circuit?

Hi , pleas where are you get library for this project

This is an amazing instructable, thank you for your time and effort, greatly appreciate it!
just wanting to know how to change it so you could have more than one master cards? I am wanting to make it so that the mastercards are set within the actual code before the system turns on, so if the system resets, I don't need to make a new mastercard.

BlueCore Tech Acces Control

MFRC522 Version: 0x92 (unknown)

and then it doesnt scan.

Any Help

1 reply

could you pleas help mine gives a error message saying the mfrc522.h file isn't found

1 reply

Hey, I just made this, and it works perfectly. Awesome design!!!

I just have one problem, when I read the master card, it says that there are 117 existing record of key cards, even though I didn't add any yet.

Any help?

Maybe it is because I don't have the KY-044 button, and I can't reset the Database...


Hi, thank you for an excellent instructable, is there a way I can add extra tags and have say 4 or 5 that will all read.

Regards Geoff

can you please share the connections details of relay to magnetic door lock Take a look at this one... adding a servo will require to much changes... you better make a new code or try another one then.


2 years ago

Nice One!!
One Question.........
How many data size stored in Arduino EEPROM for one user?


2 years ago

vandenbrande, thanks for the great instructable!

question: What’s the difference between the blue and the red version of the
rfid scanner?

1 reply

Hi, the red one has the pins set differently on the module itself. That's why i mentioned that i used the blue version. For as far as i know. I am not sure if all red ones have the same of different pins.