Enumerations
enum class	AccessResult : uint8_t { AccessResult::Denied , AccessResult::Granted , AccessResult::Denied , AccessResult::Granted }
	Access result enumeration. More...

Functions
MFRC522	mfrc522 (RFID_SS_PIN, RFID_RST_PIN)
	MFRC522 RFID reader instance.
LiquidCrystal_I2C	lcd (LCD_ADDRESS, LCD_COLUMNS, LCD_ROWS)
	I2C LCD instance.
void	lcdPrintLine (const __FlashStringHelper *msg, uint8_t line)
	Clears an LCD line and prints a flash-resident string.
void	lcdPrintLine (const char *msg, uint8_t line)
	Clears an LCD line and prints a RAM-resident string.
static void	forceLock ()
	Forces the system back into locked idle state.
void	makeEnteredPins (uint8_t pinLength)
	Builds a masked PIN string for LCD display.
void	callback (char topic, byte payload, unsigned int length)
	MQTT message callback handler.
bool	isDisplayActive (uint32_t now)
	Checks whether the LCD backlight should remain active.
void	onMotionDetected (uint32_t now)
	Handles motion-detected events.
void	onMotionIdle (uint32_t now)
	Handles motion-idle state.
void	updateMotionState (uint32_t now)
	Updates motion state based on PIR sensor input.
void	uidToHexString (const MFRC522::Uid &uid, char *output, size_t outputSize)
	Converts an RFID UID to a hexadecimal string.
void	handleRFID ()
	Handles RFID card detection and request publishing.
void	setup ()
	Arduino setup function.
void	loop ()
	Arduino main loop.

Variables
WifiMqttClient	net
	WiFi + MQTT client wrapper.
constexpr char	WIFI_SSID [] = "Mathias2.4"
	WiFi SSID.
constexpr char	WIFI_PASS [] = "mrbombasticcallmefantastic"
	WiFi password.
constexpr char	MQTT_HOST [] = "maqiatto.com"
	MQTT broker hostname.
constexpr uint16_t	MQTT_PORT = 1883
	MQTT broker port.
constexpr char	MQTT_USER [] = "hectorfoss@gmail.com"
	MQTT username.
constexpr char	MQTT_PASS [] = "potter"
	MQTT password.
constexpr char	DEVICE_ID [] = "door1"
	Unique device identifier used in MQTT topics.
constexpr uint8_t	RFID_SS_PIN = 15
	RC522 SPI Slave Select pin (D8 / GPIO15).
constexpr uint8_t	RFID_RST_PIN = 16
	RC522 Reset pin (D0 / GPIO16).
constexpr uint8_t	MOTION_PIN = 0
	Motion sensor pin (D3 / GPIO0).
constexpr uint8_t	I2C_SDA_PIN = 4
	I2C SDA pin for LCD (D2 / GPIO4).
constexpr uint8_t	I2C_SCL_PIN = 5
	I2C SCL pin for LCD (D1 / GPIO5).
constexpr uint8_t	LCD_COLUMNS = 16
	Number of LCD columns.
constexpr uint8_t	LCD_ROWS = 2
	Number of LCD rows.
constexpr uint8_t	LCD_ADDRESS = 0x27
	I2C address of the LCD module.
constexpr uint32_t	DISPLAY_MS = 3000
	Duration (ms) to display text before resetting.
constexpr uint32_t	DISPLAY_BACKLIGHT_MS = 5000
	Duration (ms) to keep LCD backlight on after motion.
constexpr uint32_t	PIN_TIME_MS = 15000
	Time window (ms) for entering PIN after RFID success.
constexpr uint32_t	UNLOCK_TIME_MS = 5000
	Door unlock display duration (ms).
constexpr uint32_t	POLL_MS = 30
	Main loop polling delay (ms).
AccessResult	rfidAccess
	Result of RFID authentication.
AccessResult	accessGranted
	Result of PIN verification.
bool	textshown = false
	Indicates whether a status message is currently displayed.
uint32_t	showTextUntil = 0
	Timestamp (ms) when the displayed text should expire.
uint32_t	showDisplayUntil = 0
	Timestamp (ms) when LCD backlight should turn off.
bool	motionActive = false
	Indicates whether motion is currently considered active.
static char	enteredPins [5] = " "
	Masked PIN buffer shown on LCD (max 4 digits + null terminator).

Detailed Description

This firmware runs on an ESP-based Arduino-compatible board and implements the first stage of a distributed door access control system.

Hardware components:

MFRC522 RFID reader (RC522)
I2C LCD display
PIR motion sensor

Functional responsibilities:

Detects motion to manage LCD backlight and user interaction
Reads RFID tags and initiates authentication
Displays system and authentication status on the LCD
Communicates authentication requests and results via MQTT

RFID authentication must succeed before the keypad stage is enabled.

Enumeration Type Documentation

◆ AccessResult

enum class AccessResult : uint8_t

strong

Access result enumeration.

Enumerator
Denied	Access denied
Granted	Access granted
Denied	Access denied
Granted	Access granted

Definition at line 130 of file esp1_rfid_motion.ino.

Function Documentation

◆ callback()

void callback	(	char *	topic,
		byte *	payload,
		unsigned int	length )

MQTT message callback handler.

Parses incoming JSON messages and dispatches logic based on topic:

RFID access decision
Keypad PIN validation result
Keypad keypress feedback

Parameters

topic	MQTT topic string.
payload	Raw payload bytes.
length	Payload length.

Definition at line 240 of file esp1_rfid_motion.ino.

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◆ forceLock()

void forceLock ( )

static

Forces the system back into locked idle state.

Resets access state, clears temporary flags, and restores the default idle LCD message.

Definition at line 196 of file esp1_rfid_motion.ino.

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◆ handleRFID()

void handleRFID ( )

Handles RFID card detection and request publishing.

Detects new cards, reads UID, updates LCD, and sends an MQTT access request.

Definition at line 440 of file esp1_rfid_motion.ino.

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◆ isDisplayActive()

bool isDisplayActive ( uint32_t now )

Checks whether the LCD backlight should remain active.

Uses signed time comparison to safely handle millis() wraparound.

Parameters

now	Current time in milliseconds.

Returns: true if display is active, false otherwise.

Definition at line 353 of file esp1_rfid_motion.ino.

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◆ lcd()

LiquidCrystal_I2C lcd	(	LCD_ADDRESS	,
		LCD_COLUMNS	,
		LCD_ROWS	)

I2C LCD instance.

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◆ lcdPrintLine() [1/2]

void lcdPrintLine	(	const __FlashStringHelper *	msg,
		uint8_t	line )

Clears an LCD line and prints a flash-resident string.

Parameters

msg	Flash string (use F("...")).
line	LCD row index.

Definition at line 170 of file esp1_rfid_motion.ino.

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◆ lcdPrintLine() [2/2]

void lcdPrintLine	(	const char *	msg,
		uint8_t	line )

Clears an LCD line and prints a RAM-resident string.

Parameters

msg	C-string to print.
line	LCD row index.

Definition at line 183 of file esp1_rfid_motion.ino.

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◆ loop()

void loop ( )

Arduino main loop.

Executes non-blocking system logic:

MQTT client processing
Display timeout handling
Motion-based backlight control
RFID polling when active

Definition at line 536 of file esp1_rfid_motion.ino.

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◆ makeEnteredPins()

void makeEnteredPins ( uint8_t pinLength )

Builds a masked PIN string for LCD display.

Converts a numeric PIN length into a visual representation using '*' characters and trailing spaces.

Parameters

pinLength Number of digits entered so far.

Definition at line 211 of file esp1_rfid_motion.ino.

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◆ mfrc522()

MFRC522 mfrc522	(	RFID_SS_PIN	,
		RFID_RST_PIN	)

MFRC522 RFID reader instance.

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◆ onMotionDetected()

void onMotionDetected ( uint32_t now )

Handles motion-detected events.

Activates LCD backlight and refreshes display timeout.

Parameters

now	Current time in milliseconds.

Definition at line 364 of file esp1_rfid_motion.ino.

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◆ onMotionIdle()

void onMotionIdle ( uint32_t now )

Handles motion-idle state.

Turns off LCD backlight when motion has ceased and the timeout has expired.

Parameters

now	Current time in milliseconds.

Definition at line 383 of file esp1_rfid_motion.ino.

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◆ setup()

void setup ( )

Arduino setup function.

Initializes hardware peripherals, LCD, WiFi, MQTT client, and topic subscriptions.

Definition at line 481 of file esp1_rfid_motion.ino.

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◆ uidToHexString()

void uidToHexString	(	const MFRC522::Uid &	uid,
		char *	output,
		size_t	outputSize )

Converts an RFID UID to a hexadecimal string.

Each UID byte is encoded as two uppercase hexadecimal characters.

Parameters

uid	MFRC522 UID structure.
output	Destination buffer.
outputSize	Size of destination buffer.

Definition at line 416 of file esp1_rfid_motion.ino.

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◆ updateMotionState()

void updateMotionState ( uint32_t now )

Updates motion state based on PIR sensor input.

Dispatches to motion-detected or motion-idle handlers.

Parameters

now	Current time in milliseconds.

Definition at line 397 of file esp1_rfid_motion.ino.

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Variable Documentation

◆ accessGranted

AccessResult accessGranted

Result of PIN verification.

Definition at line 139 of file esp1_rfid_motion.ino.

◆ DEVICE_ID

char DEVICE_ID[] = "door1"

constexpr

Unique device identifier used in MQTT topics.

Definition at line 60 of file esp1_rfid_motion.ino.

◆ DISPLAY_BACKLIGHT_MS

uint32_t DISPLAY_BACKLIGHT_MS = 5000

constexpr

Duration (ms) to keep LCD backlight on after motion.

Definition at line 102 of file esp1_rfid_motion.ino.

◆ DISPLAY_MS

uint32_t DISPLAY_MS = 3000

constexpr

Duration (ms) to display text before resetting.

Definition at line 99 of file esp1_rfid_motion.ino.

◆ enteredPins

char enteredPins[5] = " "

static

Masked PIN buffer shown on LCD (max 4 digits + null terminator).

Filled with '*' for entered digits and spaces for remaining slots.

Definition at line 158 of file esp1_rfid_motion.ino.

◆ I2C_SCL_PIN

uint8_t I2C_SCL_PIN = 5

constexpr

I2C SCL pin for LCD (D1 / GPIO5).

Definition at line 79 of file esp1_rfid_motion.ino.

◆ I2C_SDA_PIN

uint8_t I2C_SDA_PIN = 4

constexpr

I2C SDA pin for LCD (D2 / GPIO4).

Definition at line 76 of file esp1_rfid_motion.ino.

◆ LCD_ADDRESS

uint8_t LCD_ADDRESS = 0x27

constexpr

I2C address of the LCD module.

Definition at line 92 of file esp1_rfid_motion.ino.

◆ LCD_COLUMNS

uint8_t LCD_COLUMNS = 16

constexpr

Number of LCD columns.

Definition at line 86 of file esp1_rfid_motion.ino.

◆ LCD_ROWS

uint8_t LCD_ROWS = 2

constexpr

Number of LCD rows.

Definition at line 89 of file esp1_rfid_motion.ino.

◆ MOTION_PIN

uint8_t MOTION_PIN = 0

constexpr

Motion sensor pin (D3 / GPIO0).

Definition at line 73 of file esp1_rfid_motion.ino.

◆ motionActive

bool motionActive = false

Indicates whether motion is currently considered active.

Definition at line 151 of file esp1_rfid_motion.ino.

◆ MQTT_HOST

char MQTT_HOST[] = "maqiatto.com"

constexpr

MQTT broker hostname.

Definition at line 51 of file esp1_rfid_motion.ino.

◆ MQTT_PASS

char MQTT_PASS[] = "potter"

constexpr

MQTT password.

Definition at line 57 of file esp1_rfid_motion.ino.

◆ MQTT_PORT

uint16_t MQTT_PORT = 1883

constexpr

MQTT broker port.

Definition at line 53 of file esp1_rfid_motion.ino.

◆ MQTT_USER

char MQTT_USER[] = "hectorfoss@gmail.com"

constexpr

MQTT username.

Definition at line 55 of file esp1_rfid_motion.ino.

◆ net

WifiMqttClient net

WiFi + MQTT client wrapper.

Definition at line 43 of file esp1_rfid_motion.ino.

◆ PIN_TIME_MS

uint32_t PIN_TIME_MS = 15000

constexpr

Time window (ms) for entering PIN after RFID success.

Definition at line 105 of file esp1_rfid_motion.ino.

◆ POLL_MS

uint32_t POLL_MS = 30

constexpr

Main loop polling delay (ms).

Definition at line 111 of file esp1_rfid_motion.ino.

◆ RFID_RST_PIN

uint8_t RFID_RST_PIN = 16

constexpr

RC522 Reset pin (D0 / GPIO16).

Definition at line 70 of file esp1_rfid_motion.ino.

◆ RFID_SS_PIN

uint8_t RFID_SS_PIN = 15

constexpr

RC522 SPI Slave Select pin (D8 / GPIO15).

Definition at line 67 of file esp1_rfid_motion.ino.

◆ rfidAccess

AccessResult rfidAccess

Result of RFID authentication.

Definition at line 136 of file esp1_rfid_motion.ino.

◆ showDisplayUntil

uint32_t showDisplayUntil = 0

Timestamp (ms) when LCD backlight should turn off.

Definition at line 148 of file esp1_rfid_motion.ino.

◆ showTextUntil

uint32_t showTextUntil = 0

Timestamp (ms) when the displayed text should expire.

Definition at line 145 of file esp1_rfid_motion.ino.

◆ textshown

bool textshown = false

Indicates whether a status message is currently displayed.

Definition at line 142 of file esp1_rfid_motion.ino.

◆ UNLOCK_TIME_MS

uint32_t UNLOCK_TIME_MS = 5000

constexpr

Door unlock display duration (ms).

Definition at line 108 of file esp1_rfid_motion.ino.

◆ WIFI_PASS

char WIFI_PASS[] = "mrbombasticcallmefantastic"

constexpr

WiFi password.

Definition at line 48 of file esp1_rfid_motion.ino.

◆ WIFI_SSID

char WIFI_SSID[] = "Mathias2.4"

constexpr

WiFi SSID.

Definition at line 46 of file esp1_rfid_motion.ino.

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ AccessResult

Function Documentation

◆ callback()

◆ forceLock()

◆ handleRFID()

◆ isDisplayActive()

◆ lcd()

◆ lcdPrintLine() [1/2]

◆ lcdPrintLine() [2/2]

◆ loop()

◆ makeEnteredPins()

◆ mfrc522()

◆ onMotionDetected()

◆ onMotionIdle()

◆ setup()

◆ uidToHexString()

◆ updateMotionState()

Variable Documentation

◆ accessGranted

◆ DEVICE_ID

◆ DISPLAY_BACKLIGHT_MS

◆ DISPLAY_MS

◆ enteredPins

◆ I2C_SCL_PIN

◆ I2C_SDA_PIN

◆ LCD_ADDRESS

◆ LCD_COLUMNS

◆ LCD_ROWS

◆ MOTION_PIN

◆ motionActive

◆ MQTT_HOST

◆ MQTT_PASS

◆ MQTT_PORT

◆ MQTT_USER

◆ net

◆ PIN_TIME_MS

◆ POLL_MS

◆ RFID_RST_PIN

◆ RFID_SS_PIN

◆ rfidAccess

◆ showDisplayUntil

◆ showTextUntil

◆ textshown

◆ UNLOCK_TIME_MS

◆ WIFI_PASS

◆ WIFI_SSID