ESP32-Based RFID Access Control System with LCD Interface

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Circuit Documentation

Summary of the Circuit

This circuit appears to be designed for an RFID-based system, utilizing an ESP32 microcontroller as the central processing unit. The ESP32 is connected to two RFID-RC522 modules, which are commonly used for RFID tag reading. Additionally, the circuit includes a 16x4 LCD display with an I2C interface for output, two LEDs (blue and yellow) with current-limiting resistors for status indication, a single-cell 18650 Li-Ion battery for power supply, and a rocker switch (SPST) to control the power flow.

Component List

Microcontroller

ESP32 - 38 pins Expansion Board: A microcontroller with Wi-Fi and Bluetooth capabilities, featuring a wide range of GPIO pins for interfacing with various peripherals.

RFID Modules

RFID-RC522: Two instances of an RFID reader module capable of reading MIFARE tags and cards, operating at 13.56 MHz.

Display

LCD Display 16x4 I2C: A 16x4 character LCD display with an I2C interface for displaying information.

LEDs

LED: Two Pin (blue): A blue LED for status indication.
LED: Two Pin (yellow): A yellow LED for status indication.

Resistors

Resistor: Two 1000 Ohm resistors used to limit current through the LEDs.

Power Supply

18650 Li-Ion: A rechargeable lithium-ion battery cell providing power to the circuit.

Switch

Rocker Switch (SPST): A single-pole single-throw rocker switch used to control the power supply to the circuit.

Wiring Details

ESP32 - 38 pins Expansion Board

VCC connected to RFID-RC522 VCC (3.3V) and 18650 Li-Ion Positive.
GND connected to RFID-RC522 GND, LCD Display GND, LEDs cathode through resistors, and Rocker Switch pin 2.
P22 connected to RFID-RC522 RST.
P5 connected to RFID-RC522 MISO.
P17 connected to RFID-RC522 MOSI.
P16 connected to RFID-RC522 SCK.
P4 and P23 connected to RFID-RC522 SDA.
P26 connected to LCD Display SCL.
P27 connected to LCD Display SDA.
3V connected to LCD Display VCC.
P15 and P2 connected to resistors pin 2 and pin 1 respectively, for current limiting to LEDs.

RFID-RC522

Two instances with connections to ESP32 as detailed above.

LCD Display 16x4 I2C

SCL connected to ESP32 P26.
SDA connected to ESP32 P27.
VCC connected to ESP32 3V.
GND connected to ESP32 GND.

LEDs

Blue LED anode connected to resistor pin 2, cathode connected to ESP32 GND.
Yellow LED anode connected to resistor pin 1, cathode connected to ESP32 GND.

Resistors

Two 1000 Ohm resistors, each connected between an LED anode and ESP32 GPIO (P15 for yellow LED, P2 for blue LED).

18650 Li-Ion

Positive connected to ESP32 VCC.
Negative connected to Rocker Switch pin 1.

Rocker Switch (SPST)

Pin 1 connected to 18650 Li-Ion Negative.
Pin 2 connected to ESP32 GND.

Documented Code

No code has been provided for the microcontroller. The documentation of the code would typically include a description of the functionality, setup, and main loop, along with any functions or libraries used. Since no code is available, this section remains empty.