How To Make RFID Passcode Door Lock DIY


Security is an essential aspect of our lives, and every homeowner needs to ensure the optimum protection of their property. The advancements in technology have introduced various lock systems designed to beef up home security. One of the most significant innovations in recent years is the RFID passcode door lock. This lock system is an efficient and convenient method to secure your home. In this article, we will show you how to make an RFID passcode door lock DIY using Arduino Nano, RF Modules, a 16×2 LCD, and a 3×4 Keypad.

Description and Specification

Arduino Nano:

The Arduino Nano is a small and compact microcontroller board that is based on the ATmega328P. It has an integrated USB interface and can be programmed using the Arduino IDE. It is ideal for projects that require a small form factor and low power consumption.


• Microcontroller: ATmega328P
• Operating Voltage: 5V
• Input Voltage: 7-12V
• Digital I/O Pins: 14 (6 PWM)
• Analog Input Pins: 8
• Flash Memory: 32 KB
• RAM: 2 KB
• Clock Speed: 16 MHz

RFID Module:

An RFID module is an electronic device that uses radio waves to communicate data between a card or tag and the reader. They are commonly used in access control systems, tracking systems, and security applications.


• Operating Frequency: 13.56 MHz
• Communication Protocol: SPI
• Operating Voltage: 5V
• Max Operating Distance: Up to 10 cm
• Data Rate: 106 kbps
• Dimensions: 40 x 60 mm

16×2 LCD:

A 16×2 LCD is a liquid crystal display module that has 16 columns and 2 rows of characters. It is commonly used for displaying text and simple graphics in various electronic projects.


• Character Size: 5×8 dots
• Operating Voltage: 5V
• Number of Characters: 16×2
• LCD Controller: HD44780
• Interface: Parallel
• Backlight: Yes
• Dimensions: 80 x 36 x 12 mm

3×4 Membrane Keypad:

A 3×4 membrane keypad is a compact and low-cost input device that consists of a matrix of buttons. It can be used for various applications such as authentication, menu selection, and data entry.


• Number of Keys: 12 (3×4 matrix)
• Operating Voltage: 3-5V
• Interface: Digital (3-wire)
• Contact Resistance: < 100 ohms
• Life Cycle: > 1 million activations
• Dimensions: 70 x 77 mm

How To Make RFID Passcode Door Lock
RFID Passcode Door Lock

Circuit Diagram of RFID Passcode Door Lock

This project can be designed using a few basic components. The circuit diagram of this project is shown below.

How To Make RFID Passcode Door Lock Circuit Diagram
RFID Passcode Door Lock Circuit Diagram

More Circuit Layouts

Components List of RFID Passcode Door Lock

Following is the list of all components used in this project:

  • 1x Arduino Nano
  • 1 X RF Modules
  • 1x 16×2 LCD
  • 1x 3×4 Keypad
  • 1X BC547 Transistor
  • 1X 1N4148 Diode
  • 1x 100 Ohm Resistor
  • 1x 5V Relay
  • 1x electric lock
  • 2x 2 Pin Terminal Blocks

Project Code Files

Gerber Files

Explanation of RFID Passcode Door Lock

Materials needed for the DIY project

Before we delve into the steps of making your RFID passcode door lock, gather all the components from the list provided above.

Building the RFID Passcode Door Lock

Step 1: Connect the RFID Reader Module to the Arduino Nano

First, connect the RFID reader module to the Arduino Nano. To make this possible, connect the module’s VCC pin to the Arduino Nano’s 5V, GND to GND, SDA to D10, and SCK to D13. This will create a suitable interface between the RFID module and the Arduino Nano.

Step 2: Connect the 3×4 Membrane Keypad to the Arduino Nano

Using a ribbon jumper wire, connect the 3×4 membrane keypad with the Arduino Nano. The keypad’s pins are typically connected to digital pins two to eight of the Arduino. These pins are set to INPUT_PULLUP mode to avoid any conflict.

Step 3: Connect the 16×2 LCD to the Arduino Nano

Connect the 16×2 LCD to the Arduino Nano using a 16-pin male connector. You can connect the LCD’s VCC pin with the Arduino Nano’s 5V pin, and GND to GND. Connect the Contrast pin to a voltage divider circuit, which further goes to the variable resister, and finally connected to the GND. Then, connect the Enable, RS, DB4, DB5, DB6, and DB7 of the LCD module to the Arduino Nano as shown in the circuit diagram above.

Step 4: Connect the Bright LEDs to the Arduino Nano

For this step, connect four LEDs to pin 22, 24, 26 and 28 of the Arduino Nano for a better visual display. These LEDs would showcase different colors to indicate specific actions carried out. This is an additional step as per your requirement which is not shown in the circuit diagram.

Step 5: Connect the 5V Relay to the Arduino Nano

In this step, we connect the 5V Relay module to drive the electronic door lock. The VCC and GND of the Relay should connect to the Arduino Nano’s 5V and GND, respectively, while the SIGNAL pin goes to the Arduino Nano’s A0 digital pin through the transistor as shown in the circuit diagram.

Coding the RFID Passcode Door Lock

Now let’s move over to coding the RFID passcode door lock. Here, we will be using the Arduino Integrated Development Environment (IDE).

The first step is to create a new sketch, and you should name the sketch “RFID Passcode Door Lock.”

You can then insert the relevant libraries into the sketch. You can download all related project files through the link given above in the components list section.

After inserting the libraries, you can proceed to set the PINs for the LEDs, Keypad, LCD, and Relay. This would make it easy for wiring the project.


Building a DIY RFID passcode door lock is an excellent way to beef up your home security. This door lock project is relatively easy to make and does not require any expensive or rare components. The process of making this door lock can be an enjoyable and engaging activity for individuals who are keen on programming and electronics. With the outlined steps above, you should be able to create your own RFID passcode door lock DIY lock without any difficulty. This door lock system will undoubtedly enhance your home’s security and give you a sense of safety.

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