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Home Security System
Author: Olteanu Robert
Master: AAC2
Project Description
The main goal for this project was to develop a security system based on IoT devices, mainly based on ESP32 development board and an RFID module and a RFID card and also a Tag which have a unique identifier to which I added some programming logic using a security keycode that user can type in using a 3×4 keypad, and for a good user experience I decided to add a small LCD 16×2 so the user can actually see if the keycode was wrong, or the card/tag he/she scanned is invalid.
Another good thing about the ESP32 is the fact that it has a built in WiFi module that allowed me to build a small dashboard in Adafruit.io where there are displayed a few information like, the current keycode, a log containing a small history and some status widgets.
Hardware Description
For the hardware parts I used:
- ESP32 Development Board → It's a low-cost, low-power system on a chip (SoC) with WiFi and dula-mode Bluetooth capabilities, it has a dual-core or a single-core microprocessor with a clock rate of up to 240 MHz. ESP32 is highly integrated with built-in switches, power amplifier, low-noise receive amplifiers, filters, and power management modules. It is engineered for mobile devices, wearable electronics, and IoT applications.[1]
- RFC522 RFID Module → Based on MFRC522 IC, is designed to create a 13.56MHz electromagnetic field that it uses to communicate with the RFID tags. The reader can communicate with a microcontroller over a 4-pin Serial Peripheral Interface (SPI). It also supports communication over I2c and UART protocols.[2]
- 3×4 Membrane Keypad → It's a 12 keys keypad, slightly raised providing feedback when pressed.
- LCD 16×2 with I2C Interface → A Liquid Crystal Display (LCD), which is a basic module and used commonly in various devices and circuits. 16×2 means it can display 16 characters per line and there are 2 lines. The Inter-Integrated Circuit (I2C) it's a bus interface connection protocol incorporated into devices for serial communication.
I attached below a diagram generated using circuito.io, but I used a version that involved less wires.
Software Description
In the table below I described all the libraries used to develop the project.
| Library | Description |
|---|---|
| SPI.h | Serial Peripheral Interface is a synchronous serial data protocol used for communicating with one ore more devices quickly |
| MFRC522.h | Standard library to interact with the MFRC522 module to read/write different types of RFID cards |
| Keypad.h | Standard library for using matrix style keypads with Arduino |
| LiquidCrystal_I2C.h | Offers a few functions to interact easily with the LCD display for displaying characters or erasing them |
| Wire.h | Allows you to communicate with I2C/TWI devices |
| Adafruit_MQTT.h | Arduino library for MQTT support, including accessing the Adafruit.io |
| Adafruit_MQTT_Client.h | Part of the Adafruit_MQTT library suite |
Next thing the software is split in two main parts:
- Initial setup - this is where all the components / modules are getting initialized
- WiFi - The ESP32 tries to connect to the configured network until succeed and it gets the IP address
- MQTT - The Adafruit.io supports data transfer using MQTT, and on this initial setup there is needed to subscribe to all topics needed
- RFC522 - Initialize the SPI Bus then initialize the RFID module.
- Loop - this is looping until the ESP32 is stopped by user.
Workflow
References
