Circuit Documentation

Summary of the Circuit

This circuit is designed to interface an Arduino UNO with several peripheral devices including a 1-Channel Relay, an I2C LCD 16x2 Screen, a 12V solenoid lock, and a Fingerprint Scanner. The Arduino UNO acts as the central controller, managing the input from the Fingerprint Scanner and controlling the state of the solenoid lock through the relay based on the authentication result. The I2C LCD screen is used to display messages or status information. The 12V power supply provides the necessary voltage for the solenoid lock, while the Arduino and other 5V components are powered by the Arduino's onboard voltage regulator.

Component List

12v Power Supply

• Description: Provides a 12V power source for the circuit.
• Pins: +, -

1-Channel Relay (5V 10A)

• Description: Acts as an electrically operated switch to control the solenoid lock.
• Pins: NC, signal, C, power, NO, ground

Arduino UNO

• Description: Microcontroller board based on the ATmega328P, used as the main controller for the circuit.
• Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0 to A5, SCL, SDA, AREF, D0 to D13

I2C LCD 16x2 Screen

• Description: Alphanumeric liquid crystal display capable of displaying 16 characters per 2 lines.
• Pins: SCL, SDA, VCC (5V), GND, VDD, VO, RS, RW, E, D0 to D7, BLA, BLK

12V Solenoid Lock

• Description: Electromechanical lock that can be controlled by the relay.
• Pins: VCC, GND

Fingerprint Scanner

• Description: Biometric sensor for scanning fingerprints.
• Pins: VCC, TX, RX, GND

Wiring Details

12v Power Supply

• + connected to Relay C
• - connected to common ground net

1-Channel Relay (5V 10A)

• NC not connected
• signal connected to Arduino UNO D4
• C connected to 12v Power Supply +
• power connected to 5V net
• NO connected to 12V Solenoid Lock VCC
• ground connected to common ground net

Arduino UNO

• 5V connected to 5V net
• GND connected to common ground net
• A4 connected to I2C LCD Screen SDA
• A5 connected to I2C LCD Screen SCL
• D2 connected to Fingerprint Scanner TX
• D3 connected to Fingerprint Scanner RX
• D4 connected to Relay signal

I2C LCD 16x2 Screen

• SCL connected to Arduino UNO A5
• SDA connected to Arduino UNO A4
• VCC (5V) connected to 5V net
• GND connected to common ground net

12V Solenoid Lock

• VCC connected to Relay NO
• GND connected to common ground net

Fingerprint Scanner

• VCC connected to 5V net
• TX connected to Arduino UNO D2
• RX connected to Arduino UNO D3
• GND connected to common ground net

Documented Code

Arduino UNO Code (sketch.ino)

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Note: The code provided is a template and does not contain any functional code. It needs to be populated with the logic for interfacing with the Fingerprint Scanner, controlling the Relay, and updating the I2C LCD Screen based on the system state.