Build Instructions

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• 1

  Understanding How the RFID Logger Works

  Before connecting any wires or uploading code, it's important to understand how the entire system operates. Once you understand the data flow, the rest of the project becomes much easier to follow.

  Unlike traditional RFID examples where the card information is only displayed on the Serial Monitor, this project sends every scanned RFID card directly to Google Sheets over Wi-Fi. This means every scan is automatically stored in the cloud and can be viewed from anywhere.

  The entire communication process is shown below.

  RFID Card               │               ▼      MFRC522 RFID Reader               │         (SPI Communication)               │               ▼        ESP32-S3-BOX-3               │         Wi-Fi Connection               │               ▼     Google Apps Script               │               ▼        Google Sheets

  Whenever an RFID card is brought close to the reader, the MFRC522 detects the card and extracts its Unique Identifier (UID). This UID is a hexadecimal number that uniquely identifies the RFID card.

  For example, a scanned UID may look like this:

  827ED600

  Once the ESP32 receives this UID, it immediately performs two actions:

  • Displays a confirmation message on the ESP32-S3-BOX-3 display.
  • Sends the UID to Google Apps Script using an HTTP request.

  Google Apps Script receives this request and automatically appends a new row to a Google Sheet along with the current date and time.

  Since Google Sheets stores all the records online, you don't need to worry about creating or maintaining a database.

• 2

  Understanding the Hardware

  Let's briefly understand the purpose of each component used in this project.

  ESP32-S3-BOX-3

  The ESP32-S3-BOX-3 acts as the brain of the project.

  It performs several important tasks simultaneously:

  • Reads RFID data from the MFRC522 module.
  • Connects to the Wi-Fi network.
  • Sends HTTP requests to Google Apps Script.
  • Displays the project status on the built-in screen.

  Because the ESP32-S3 includes built-in Wi-Fi, we don't need any additional communication modules.

  MFRC522RFID Reader

  The MFRC522 is one of the most popular low-cost RFID readers available for Arduino and ESP32 projects.

  It operates at 13.56 MHz and communicates with the ESP32 using the SPI protocol.

  Whenever an RFID card enters its reading range, the module extracts the UID and sends it to the ESP32.

  The typical reading distance is around 2–5 cm, depending on the RFID card and antenna orientation.

  RFIDCard

  Each RFID card contains a small integrated circuit and antenna.

  Every card has its own unique UID, which acts like a digital fingerprint.

  For example:

  Card 1827ED600-------------------Card 22A7E17B1-------------------Card 3D784D500

  Throughout this tutorial, only the UID will be stored in Google Sheets.

  Later, you can modify the software to associate each UID with a person's name, employee ID, student record, or any other information.

• 3

  Understanding SPI Communication

  The MFRC522 communicates with the ESP32 using the SPI (Serial Peripheral Interface) protocol.

  SPI is one of the fastest communication methods available for embedded systems and is commonly used with displays, SD cards, RFID modules, and other high-speed peripherals.

  The communication uses four primary signals:

  SCK: Clock signal generated by the ESP32

  MOSI: Data sent from ESP32 to RFID module

  MISO: Data sent from RFID module to ESP32

  SDA(SS): Chip Select signal

  The ESP32-S3-Box3 uses the following pin mapping:

  MFRC522 Pin -> ESP32-S3-BOX-3 Pin

  SDA - GPIO 10

  SCK - GPIO 12

  MOSI - GPIO 11

  MISO - GPIO 13

  3.3v - 3.3v

  GND - GND

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