Circuit Documentation

Summary

The circuit in question is designed to interface various sensors and output devices with an ESP32 microcontroller. The circuit includes environmental sensing through a DHT22 temperature and humidity sensor, gas detection via an MQ-5 sensor, visual feedback through red and green LEDs, audible alerts with a buzzer, and a 20x4 LCD display with I2C interface for data display. The ESP32 serves as the central processing unit, managing sensor readings, controlling the LEDs and buzzer, and updating the display.

Component List

LEDs

• Red LED: A two-pin red LED used for visual indication.
• Green LED: A two-pin green LED used for visual indication.

Sensors

• DHT22: A sensor for measuring temperature and humidity.
• MQ-5 Gas Sensor: A sensor for detecting various gases, including natural gas and LPG.

Output Devices

• Buzzer: An audible alert device.
• LCD 20x4 I2C: A 20x4 character LCD display with an I2C interface for displaying data.

Passive Components

• Resistors: Two 330 Ohm resistors used for current limiting for the LEDs.

Microcontroller

• ESP32: A microcontroller with Wi-Fi and Bluetooth capabilities, used as the central processing unit of the circuit.

Wiring Details

Red LED

• Cathode: Connected to the ESP32's GND.
• Anode: Connected to one end of a 330 Ohm resistor, whose other end is connected to the ESP32's D4 pin.

Green LED

• Cathode: Connected to the ESP32's GND.
• Anode: Connected to one end of a 330 Ohm resistor, whose other end is connected to the ESP32's D2 pin.

DHT22 Sensor

• +: Connected to the ESP32's 3V3 pin.
• Out: Connected to the ESP32's D15 pin.
• -: Connected to the ESP32's GND.

MQ-5 Gas Sensor

• VCC: Connected to the ESP32's VIN pin.
• GND: Connected to the ESP32's GND.
• Digi Out: Not connected in this circuit.
• Analog out: Connected to the ESP32's D34 pin.

Buzzer

• PIN: Connected to the ESP32's D5 pin.
• GND: Connected to the ESP32's GND.

LCD 20x4 I2C

• GND: Connected to the ESP32's GND.
• 5v: Connected to the ESP32's 3V3 pin.
• SCA: Connected to the ESP32's D21 pin.
• SCL: Connected to the ESP32's D22 pin.

Documented Code

There is no code provided for the microcontroller. The documentation of the code would typically include setup routines, main loop logic, function definitions, and any interrupt service routines, along with comments explaining the purpose and functionality of each section of the code. Since no code is available, this section cannot be completed.