Circuit Documentation

Summary

This circuit involves an Arduino Nano microcontroller interfacing with various components including an MQ-2 gas sensor, a servo motor, a 2-channel relay, a buzzer, LEDs, a fan, a bulb, and a 12V battery. The circuit is designed to control the relay, LEDs, buzzer, and servo motor based on inputs from the MQ-2 sensor. The fan and bulb are controlled through the relay.

Component List

Arduino Nano

• Description: A small, complete, and breadboard-friendly board based on the ATmega328P.
• Pins: D1/TX, D0/RX, RESET, GND, D2, D3, D4, D5, D6, D7, D8, D9, D10, D11/MOSI, D12/MISO, VIN, 5V, A7, A6, A5, A4, A3, A2, A1, A0, AREF, 3V3, D13/SCK

MQ-2

• Description: Gas sensor for detecting LPG, i-butane, propane, methane, alcohol, Hydrogen, and smoke.
• Pins: GND, VCC, ANALOG, Digital

Servo

• Description: A small motor with a feedback mechanism for precise control of angular position.
• Pins: GND, VCC, PWM

2ch Relay

• Description: A 2-channel relay module for controlling high voltage devices.
• Pins: NC, COM, NO, VCC, IN2, IN1, GND

Power 220V

• Description: Standard 220V power supply.
• Pins: hot wire, neutral wire

Bulb

• Description: Standard light bulb.
• Pins: GND, power

Fan

• Description: A small fan for cooling purposes.
• Pins: GND, 5V

Battery 12V

• Description: A 12V battery for powering components.
• Pins: +, -

LED: Two Pin (green)

• Description: A green LED.
• Pins: cathode, anode

LED: Two Pin (red)

• Description: A red LED.
• Pins: cathode, anode

Buzzer

• Description: A small buzzer for sound output.
• Pins: PIN, GND

Wiring Details

Arduino Nano

• GND connected to:

  • Buzzer GND
  • Red LED cathode
  • MQ-2 GND
  • 2ch Relay GND
  • Green LED cathode
  • Servo GND

• D2 connected to:

  • Green LED anode

• D3 connected to:

  • Red LED anode

• D4 connected to:

  • Buzzer PIN

• D5 connected to:

  • 2ch Relay IN1

• D6 connected to:

  • 2ch Relay IN2

• D8 connected to:

  • MQ-2 ANALOG

• D9 connected to:

  • Servo PWM

• 5V connected to:

  • MQ-2 VCC
  • 2ch Relay VCC
  • Servo VCC

MQ-2

• GND connected to:

  • Arduino Nano GND

• VCC connected to:

  • Arduino Nano 5V

• ANALOG connected to:

  • Arduino Nano D8

Servo

• GND connected to:

  • Arduino Nano GND

• VCC connected to:

  • Arduino Nano 5V

• PWM connected to:

  • Arduino Nano D9

2ch Relay

• GND connected to:

  • Arduino Nano GND

• VCC connected to:

  • Arduino Nano 5V

• IN1 connected to:

  • Arduino Nano D5

• IN2 connected to:

  • Arduino Nano D6

• NC connected to:

  • Fan GND
  • Power 220V neutral wire

• COM connected to:

  • Battery 12V -
  • Bulb GND

Power 220V

• neutral wire connected to:

  • 2ch Relay NC

• hot wire connected to:

  • Bulb power

Bulb

• GND connected to:

  • 2ch Relay COM

• power connected to:

  • Power 220V hot wire

Fan

• GND connected to:

  • 2ch Relay NC

• 5V connected to:

  • Battery 12V +

Battery 12V

• - connected to:

  • 2ch Relay COM

• + connected to:

  • Fan 5V

LED: Two Pin (green)

• cathode connected to:

  • Arduino Nano GND

• anode connected to:

  • Arduino Nano D2

LED: Two Pin (red)

• cathode connected to:

  • Arduino Nano GND

• anode connected to:

  • Arduino Nano D3

Buzzer

• GND connected to:

  • Arduino Nano GND

• PIN connected to:

  • Arduino Nano D4

Documented Code

Arduino Nano Code (sketch.ino)

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

}

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

}

Additional Documentation (documentation.txt)