Magnetic Door System

A IoT door lock mechanism

info

Author: Pică Sebastian
GitHub Project Link: https://github.com/UPB-PMRust-Students/project-SebiP21

Description

The Smart Magnetic Door Lock System is a security device that lets you open a door using a keypad and checks if the door was opened. If the correct password is entered on the keypad, a servo motor unlocks the door. A magnetic sensor on the door checks if it has actually been opened. When the door opens, an LED turns on and the system sends a message over Wi-Fi. The Raspberry Pi Pico W handles everything and stores the passwords on an SD card.

Motivation

The reason why I chose this project is because it combines several interesting and useful features: a password-protected door lock, door status detection, and Wi-Fi notifications. I believe that this project is a great way to learn how to use components like a keypad, servo motor, SD card, and magnetic sensor with a Raspberry Pi Pico W.

Architecture

This is the description of the system components and their interactions:

1. Keypad

   • The keypad is the user input interface.
   • Users input a numeric password which is read by the microcontroller.

2. Raspberry Pi Pico W

   • Acts as the brain of the system.
   • Reads the keypad input and compares it against a list of valid passwords stored on an SD card.
   • If the password is correct, it sends a signal to open the servo motor.
   • Monitors the magnetic sensor for door state changes.
   • Sends a Wi-Fi message if the door is opened.

3. SD Card Module

   • Stores one or more valid passwords in a text file.
   • Connected to the Pico via SPI.

4. Servo Motor

   • Mechanically unlocks the door when the correct password is entered.

5. Magnetic Sensor (Hall Effect)

   • Detects whether the door is physically opened.
   • Triggers the LED and Wi-Fi alert if the door is open.

6. LED

   • Lights up when the door has been opened.

7. Wi-Fi Messaging

   • The Pico W sends a message over Wi-Fi when the door is opened.

Log

Week 28 - 4 May

I have started the project following the steps to set-up the gitlab page and I have sketched the documentations

Week 5 - 11 May

I bought all the parts for the project and began to assemble it. I have also written the first lines of code for the sofware

Week 12 - 18 May

I finished assembeling the project with only minor things left to sort out

Week 19 - 25 May

Hardware

The project uses the following components:

1. Raspberry Pi Pico W – Central controller.
2. 4x4 Keypad – User input interface for password entry.
3. Servo Motor – Controls the door lock mechanism.
4. Magnetic Sensor – Detects whether the door is open.
5. LED (5 mm) – Visual indicator for door-open event.
6. SD Card Module – Stores passwords in a file.
7. USB – Powers the Pico and servo.

Schematics

This is the Kicad Schematic: Instead of a keypad schematic I have used connection pins to represent the rows and columns of the keypad in the KiCad representation of the project

Bill of Materials

Device	Usage	Price
Raspberry Pi Pico W	Main microcontroller	35 RON
4x4 Keypad	User password input	6.99 RON
MG996 Micro Servo	Controls door lock	29.99 RON
LED 5 mm	Lights up when door opens	0.39 RON
SD Card Module	Stores passwords	4.39 RON
MicroSD Card (8GB)	Stores password file	15.99 RON
Breadboard & Wires	For prototyping	11.90 RON

Software

Library	Description	Usage
embedded-sdmmc	SD card file system interface	Reads password data
embedded-hal-servo	Servo control	Opens door on valid password
embassy	Async embedded framework	Powers the system’s concurrency
panic-halt	Handles panic safely	Halts system on unrecoverable errors

Links

// Add a few links that inspired you and that you think you will use for your project