Circuit Documentation

Summary of the Circuit

This circuit is designed around an Arduino UNO microcontroller, which serves as the central processing unit. The circuit includes a variety of components such as pushbuttons, a piezo buzzer, an LCD display with I2C interface, a 5V relay, a battery pack, and a door sensor (MC-38). The pushbuttons are used as input devices, the piezo buzzer as an output audio signal device, the LCD display for visual output, the relay for controlling higher power loads, and the door sensor as a security input device. The battery pack provides power to the circuit.

Component List

Arduino UNO

• Microcontroller board based on the ATmega328P
• Provides digital and analog I/O pins
• Can be powered via the USB connection or with an external power supply

Pushbuttons (x8)

• Simple switch mechanism for control or input
• Each button has four pins: two for the switch operation (in) and two for the output state (out)

Piezo Buzzer

• Electronic device that produces sound when an electrical signal is applied
• Typically used for generating beeps, alerts, and tones

LCD 20x4 I2C

• Alphanumeric liquid crystal display
• Capable of displaying 4 lines of 20 characters
• Uses I2C communication protocol for interfacing with the microcontroller

5V Relay

• Electromechanical switch used to control a high power circuit with a low power signal
• Has a coil rated at 5V and contacts that can switch AC or DC loads

Battery Pack

• Provides a power source for the circuit
• Typically consists of multiple batteries connected together to provide the required voltage and current

Door MC-38

• Magnetic contact switch that detects door open/close events
• Commonly used in security systems

Wiring Details

Arduino UNO

• 5V connected to LCD 20x4 i2c 5v, 5V relay VCC
• GND connected to LCD 20x4 i2c GND, 5V relay GND, Battery pack -, and common ground for all pushbuttons and Piezo Buzzer
• Vin connected to Battery pack +
• A4 connected to LCD 20x4 i2c SCA
• A5 connected to LCD 20x4 i2c SCL
• D13 connected to Piezo Buzzer pin 2
• D11, D10, D9, D8, D7, D6, D5, D4 connected to respective pushbutton Pin 4 (out)
• D2 connected to Door MC-38 S
• D1 connected to 5V relay In

Pushbuttons

• Pin 2 (in) of all pushbuttons connected to common ground
• Pin 4 (out) of each pushbutton connected to a unique digital pin on the Arduino UNO

Piezo Buzzer

• pin 1 connected to common ground
• pin 2 connected to Arduino UNO D13

LCD 20x4 I2C

• 5v connected to Arduino UNO 5V
• GND connected to Arduino UNO GND
• SCA connected to Arduino UNO A4
• SCL connected to Arduino UNO A5

5V Relay

• VCC connected to Arduino UNO 5V
• GND connected to Arduino UNO GND
• In connected to Arduino UNO D1

Battery Pack

• + connected to Arduino UNO Vin
• - connected to common ground

Door MC-38

• S connected to Arduino UNO D2
• GND connected to common ground

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 provided code is a template and does not include any functional code. It needs to be populated with the logic to handle the inputs from the pushbuttons, door sensor, and to control the outputs such as the LCD display, piezo buzzer, and the relay.