Hardware and Wiring

Hardware and Wiring

Hardware Required

Component	Notes
ESP32-S3 dev board	QFN56, rev v0.2, 8MB Octal PSRAM, 16MB Flash, 40MHz XTAL (as tested)
PN532 NFC/RFID module V3	Must be set to SPI mode via onboard DIP switches, see below
16x2 LCD with PCA8574 I2C backpack	Address is usually 0x27 or 0x3F, see Troubleshooting
Passive buzzer	Connected to GPIO 6, see below
USB-C / micro-USB cable	Data-capable, not charge-only
Breadboard + jumper wires
Wi-Fi network (2.4GHz)	Required for NTP time sync -- see Python CLI Guide

Software Required

• Arduino IDE 2.x
• ESP32 board package (via Boards Manager), v3.x recommended
• Libraries (Library Manager):
  • Adafruit PN532
  • LiquidCrystal I2C (Frank de Brabander / Marco Schwartz fork)
  • ArduinoJson (v7.x)
  • WiFi and Preferences -- ship with the ESP32 board package
• Python 3.9+ for the CLI, with pip install -r python_cli/requirements.txt

PN532: Configuring SPI Mode

SW1	SW2	Mode
ON	OFF	SPI (use this)
OFF	OFF	HSU (UART)
OFF	ON	I2C
ON	ON	Reserved / invalid

Set SW1 = ON, SW2 = OFF. If getFirmwareVersion() prints 0x0 at boot, DIP switches are wrong or MISO/MOSI are swapped.

Wiring

A wiring diagram (Wiring.png) ships in the repo root.

SPI: ESP32-S3 to PN532

ESP32-S3 GPIO	PN532 Pin	Signal
GPIO 12	SCK	SPI Clock
GPIO 13	MISO	SPI Master In
GPIO 11	MOSI	SPI Master Out
GPIO 10	SS / NSS	Chip Select
3V3	VCC	Power (do not use 5V)
GND	GND	Ground

I2C: ESP32-S3 to 16x2 LCD

ESP32-S3 GPIO	LCD Backpack Pin	Signal
GPIO 8	SDA	I2C Data
GPIO 9	SCL	I2C Clock
5V	VCC	Power (May require an external power supply)
GND	GND	Ground

Buzzer (passive)

ESP32-S3 GPIO	Buzzer Pin	Signal
GPIO 6	Signal/+	PWM tone (driven via tone()/ledc)
GND	-	Ground

Must be a passive buzzer (driven by PWM tone), not active. Access Granted plays a ~1.5s ascending 4-note tone; Access Denied plays a descending one.

Power

The LCD backpack requires a 5V power supply. Power from a separate 5V source (or VBUS pin), and tie all GND wires together.