Circuit Documentation

Summary of the Circuit

This circuit is designed to interface various sensors and modules with an Arduino UNO microcontroller. The sensors include an MQ-5 gas sensor, a DHT11 humidity and temperature sensor, and a PM2.5 air quality sensor. The circuit also includes a 0.96" OLED display for data visualization, a buzzer for audible alerts, and an HC-05 Bluetooth module for wireless communication. A 9V battery powers the entire circuit. The Arduino UNO reads sensor data and controls the output to the display and buzzer based on the sensor inputs. It can also communicate sensor data wirelessly via the Bluetooth module.

Component List

MQ-5 Gas Sensor

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

Buzzer

• Pins: POSITIVE, NEGATIVE
• Description: An audible signaling device.

DHT11 Humidity and Temperature Sensor

• Pins: VDD, DATA, NULL, GND
• Description: A sensor for measuring ambient humidity and temperature.

0.96" OLED Display

• Pins: GND, VDD, SCK, SDA
• Description: A small display for showing graphical and textual data.

PM2.5 Air Quality Sensor

• Pins: control 1, Vout2, VCC, Vout1, GND
• Description: A sensor for measuring particulate matter in the air.

Arduino UNO

• Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0-A5, SCL, SDA, AREF, D0-D13
• Description: A microcontroller board based on the ATmega328P.

HC-05 Bluetooth Module

• Pins: Key, VCC, GND, TXD, RXD, State
• Description: A wireless communication module for Bluetooth connectivity.

9V Battery

• Pins: -, +
• Description: A power source for the circuit.

Wiring Details

MQ-5 Gas Sensor

• VCC: Connected to 5V from the Arduino UNO.
• GND: Connected to GND from the Arduino UNO.
• Analog out: Connected to A0 on the Arduino UNO.

Buzzer

• POSITIVE: Connected to D8 on the Arduino UNO.
• NEGATIVE: Connected to GND from the Arduino UNO.

DHT11 Humidity and Temperature Sensor

• VDD: Connected to 5V from the Arduino UNO.
• DATA: Connected to D7 on the Arduino UNO.
• GND: Connected to GND from the Arduino UNO.

0.96" OLED Display

• VDD: Connected to 5V from the Arduino UNO.
• GND: Connected to GND from the Arduino UNO.
• SCK: Connected to A5 on the Arduino UNO.
• SDA: Connected to A4 on the Arduino UNO.

PM2.5 Air Quality Sensor

• VCC: Connected to 5V from the Arduino UNO.
• Vout1: Connected to A1 on the Arduino UNO.
• GND: Connected to GND from the Arduino UNO.

HC-05 Bluetooth Module

• VCC: Connected to 5V from the Arduino UNO.
• GND: Connected to GND from the Arduino UNO.
• TXD: Connected to D10 on the Arduino UNO.
• RXD: Connected to D11 on the Arduino UNO.

9V Battery

• +: Connected to 5V from the Arduino UNO.
• -: Connected to GND from the Arduino UNO.

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:

}

Additional Notes

• The code provided for the Arduino UNO is a template with empty setup and loop functions. The actual implementation should include initialization of the sensors and modules, reading sensor data, controlling the OLED display and buzzer, and handling Bluetooth communication.
• The HC-05 Bluetooth module is wired for serial communication with the Arduino UNO, which will allow for wireless data transmission.
• The 9V battery is assumed to be connected to the Arduino UNO's Vin pin or the barrel jack to provide power to the board, although this is not explicitly stated in the wiring details.