Circuit Documentation

Summary

This document provides a detailed overview of a circuit that includes an Arduino UNO microcontroller, a DC motor controlled by an L293D motor driver, a Li-ion battery, a 9V battery, an MQ-5 gas sensor, a green LED, a rocker switch, and a 16x2 I2C LCD display. The circuit is designed to control the DC motor and display sensor readings on the LCD.

Component List

1. Arduino UNO

   • Description: A microcontroller board based on the ATmega328P.
   • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

2. Li-ion battery 18650-2000mAh 3.7V 7.4WH

   • Description: A rechargeable lithium-ion battery.
   • Pins: +, -

3. DC Motor

   • Description: A simple DC motor.
   • Pins: pin 1, pin 2

4. L293D

   • Description: A quadruple high-current half-H driver.
   • Pins: Enable 1,2, Input 1, Output 1, GND, Output 2, Input 2, Vcc2, Vcc1, Input 4, Output 4, Output 3, Input 3, Enable 3,4

5. LED: Two Pin (green)

   • Description: A green LED with two pins.
   • Pins: cathode, anode

6. MQ-5

   • Description: A gas sensor for detecting LPG, natural gas, and coal gas.
   • Pins: VCC, GND, Digi Out, Analog out

7. 9V battery

   • Description: A standard 9V battery.
   • Pins: +, -

8. Rocker Switch

   • Description: A simple on/off rocker switch.
   • Pins: 1, 2

9. 16x2 I2C LCD

   • Description: A 16x2 character LCD display with I2C interface.
   • Pins: GND, VCC, SDA, SCL

Wiring Details

Arduino UNO

• 5V connected to:

  • L293D (Enable 1,2)
  • L293D (Vcc1)
  • MQ-5 (VCC)

• D5 connected to:

  • L293D (Input 1)

• GND connected to:

  • Li-ion battery (18650-2000mAh 3.7V 7.4WH) (-)
  • L293D (GND)
  • MQ-5 (GND)
  • Rocker Switch (1)
  • 9V battery (-)
  • LED (cathode)

• Vin connected to:

  • 9V battery (+)

• A0 connected to:

  • MQ-5 (Analog out)

• A4 connected to:

  • 16x2 I2C LCD (SDA)

• A5 connected to:

  • 16x2 I2C LCD (SCL)

• D8 connected to:

  • Rocker Switch (2)

• D7 connected to:

  • LED (anode)

• D6 connected to:

  • L293D (Input 2)

Li-ion battery 18650-2000mAh 3.7V 7.4WH

• + connected to:
  • L293D (Vcc2)

DC Motor

• pin 1 connected to:

  • L293D (Output 1)

• pin 2 connected to:

  • L293D (Output 2)

L293D

• Enable 1,2 connected to:

  • Arduino UNO (5V)

• Input 1 connected to:

  • Arduino UNO (D5)

• Output 1 connected to:

  • DC Motor (pin 1)

• GND connected to:

  • Arduino UNO (GND)
  • Li-ion battery (18650-2000mAh 3.7V 7.4WH) (-)
  • MQ-5 (GND)
  • Rocker Switch (1)

• Output 2 connected to:

  • DC Motor (pin 2)

• Input 2 connected to:

  • Arduino UNO (D6)

• Vcc2 connected to:

  • Li-ion battery (18650-2000mAh 3.7V 7.4WH) (+)

• Vcc1 connected to:

  • Arduino UNO (5V)

LED: Two Pin (green)

• cathode connected to:

  • Arduino UNO (GND)

• anode connected to:

  • Arduino UNO (D7)

MQ-5

• VCC connected to:

  • Arduino UNO (5V)

• GND connected to:

  • Arduino UNO (GND)

• Analog out connected to:

  • Arduino UNO (A0)

9V battery

• + connected to:

  • Arduino UNO (Vin)

• - connected to:

  • Arduino UNO (GND)

Rocker Switch

• 1 connected to:

  • Arduino UNO (GND)

• 2 connected to:

  • Arduino UNO (D8)

16x2 I2C LCD

• GND connected to:

  • Arduino UNO (GND)

• VCC connected to:

  • Arduino UNO (5V)

• SDA connected to:

  • Arduino UNO (A4)

• SCL connected to:

  • Arduino UNO (A5)

Documented Code

sketch.ino

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

}

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

}

documentation.txt