# RFID Access Control

Day 72 of the 100 Days 100 IoT Projects collection. Board: ESP8266.

Tap an RFID card to unlock — an ESP8266 with MFRC522 grants or denies access. Keycards, DIY style.

## How it works

Tapping a card wakes the MFRC522 reader, which pulls the card's UID over SPI. The ESP8266 checks that UID against its list of authorized cards and either unlocks or denies with feedback. Keycards without the enterprise price tag.

## What you'll learn

- RFID UID authentication
- SPI RFID readers
- Authorized-list logic
- Grant/deny feedback design

Full project (code, wiring diagram, Wokwi simulation): https://github.com/kritishmohapatra/100_Days_100_IoT_Projects/tree/main/RFID_Basic_Access_Control_System

Summary by SkillShop. Code and diagrams belong to the original repo.