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Artefacte grafice (ale texturilor) in aplicatii 2D sau 3D pe terminale iOS/Android (ARM)

Daca se respecta anumite “conditii”, desi dispozitivul este sau a fost perfect functional fara a avea disfunctionalitati de natura hardware, putem observa ca in anumite aplicatii si/sau motoare grafice texturile/imaginile/loading bars fie sunt albe sau incarca lent, fie prezinta tipare de culori la intamplare.

Desigur, sunt posibile si alte simptome dar cele de mai sus au fost observate si remediate cu metoda prezentata in continuare.

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Arduino Fingerprint Sensor

Required Components

Component Quantity Description
Arduino Uno / Nano / Mega 1 Main controller
Fingerprint Sensor (R307 / ZFM-20 / Adafruit) 1 Biometric identification
16×2 LCD with I2C Module 1 Display user messages
12V Solenoid Lock 1 Door/box locking mechanism
5V Relay Module 1 Controls solenoid lock
12V Power Supply 1 Powers solenoid
Jumper Wires – Connections

The fingerprint sensor scans the user’s finger. Arduino checks if the fingerprint matches a stored ID. If it matches, the relay is activated and unlocks the solenoid lock. The LCD shows:

  • Scanning
  • Access Granted
  • Access Denied

Fingerprint Sensor → Arduino

VCC → 5V
GND → GND
TX  → D2
RX  → D3

I2C LCD → Arduino

VCC → 5V
GND → GND
SDA → A4
SCL → A5

Relay Module → Arduino

IN  → D8
VCC → 5V
GND → GND

Solenoid Lock Power Wiring

12V+ → COM on Relay
NO   → Solenoid +
Solenoid - → 12V -

IMPORTANT: Use a diode (1N4007) across solenoid terminals to prevent voltage spikes.

Arduino Code (Copy & Paste)

This code controls the fingerprint module, LCD display, and solenoid lock.


#include <Adafruit_Fingerprint.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <SoftwareSerial.h>

SoftwareSerial fingerSerial(2, 3); // RX, TX
Adafruit_Fingerprint finger = Adafruit_Fingerprint(&fingerSerial);
LiquidCrystal_I2C lcd(0x27, 16, 2);

int relayPin = 8;

void setup() {
lcd.init();
lcd.backlight();

pinMode(relayPin, OUTPUT);
digitalWrite(relayPin, LOW); // lock OFF at start

lcd.setCursor(0, 0);
lcd.print("Fingerprint");
lcd.setCursor(0, 1);
lcd.print("Access System");

delay(2000);
lcd.clear();

finger.begin(57600);
if (finger.verifyPassword()) {
lcd.print("Sensor Ready");
} else {
lcd.print("Sensor Error");
while (1);
}
delay(2000);
lcd.clear();
}

void loop() {
lcd.setCursor(0, 0);
lcd.print("Place Finger...");
lcd.setCursor(0, 1);
lcd.print(" ");

int result = getFingerprintID();

if (result >= 0) {
lcd.clear();
lcd.print("Access Granted");
unlockDoor();
} else if (result == -1) {
lcd.clear();
lcd.print("Access Denied");
delay(1500);
}

lcd.clear();
}

int getFingerprintID() {
finger.getImage();
if (finger.image2Tz() != FINGERPRINT_OK) return -1;
if (finger.fingerSearch() != FINGERPRINT_OK) return -1;

return finger.fingerID; // valid ID returned
}

void unlockDoor() {
digitalWrite(relayPin, HIGH); // open lock
delay(3000); // unlock duration
digitalWrite(relayPin, LOW); // lock again
}

You must add fingerprints before using the system.

  1. In Arduino IDE, go to File → Examples → Adafruit Fingerprint Sensor Library → Enroll
  2. Upload the sketch
  3. Open Serial Monitor
  4. Type the fingerprint ID number (1–127)
  5. Place finger twice when instructed

Fingerprint is now stored.

LCD Display Messages

Event Message
Startup Fingerprint Access System
Ready Sensor Ready
Waiting Place Finger…
Match Access Granted
No Match Access Denied

Troubleshooting

  • Fingerprint not detected: TX/RX wiring reversed
  • LCD not showing text: Wrong I2C address (try 0x3F)
  • Solenoid not activating: Check relay NO/COM wiring
  • Machine resets: Solenoid drawing current — use separate 12V supply.
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