Circuit Documentation

Summary

This document provides a detailed overview of a circuit that includes an ESP32 microcontroller, an MQ135 gas sensor, a DHT22 temperature and humidity sensor, a buzzer, an LCD 20x4 display with I2C interface, and a 5V battery. The circuit is designed to monitor environmental conditions and provide visual and audible alerts.

Component List

ESP32 (30 pin)

• Description: A powerful microcontroller with built-in Wi-Fi and Bluetooth capabilities.
• Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, Vin, D23, D22, TX0, RX0, D21, D19, D18, D5, TX2, RX2, D4, D2, D15, 3V3

MQ135

• Description: A gas sensor used to detect air quality.
• Pins: VCC, GND, A0, D0

DHT22

• Description: A temperature and humidity sensor.
• Pins: GND, VCC, DAT

Buzzer

• Description: An electronic component that emits sound.
• Pins: PIN, GND

LCD 20x4 I2C

• Description: A 20x4 character LCD display with I2C interface.
• Pins: GND, 5V, SCA, SCL

5V Battery

• Description: A power source providing 5V.
• Pins: Positive, Negative

Wiring Details

ESP32 (30 pin)

• 3V3: Connected to VCC of MQ135 and VCC of DHT22
• GND: Connected to GND of MQ135, GND of Buzzer, and GND of DHT22
• D35: Connected to A0 of MQ135
• D27: Connected to PIN of Buzzer
• D22: Connected to SCL of LCD 20x4 I2C
• D21: Connected to SCA of LCD 20x4 I2C
• D4: Connected to DAT of DHT22

MQ135

• VCC: Connected to 3V3 of ESP32
• GND: Connected to GND of ESP32
• A0: Connected to D35 of ESP32

DHT22

• VCC: Connected to 3V3 of ESP32
• GND: Connected to GND of ESP32
• DAT: Connected to D4 of ESP32

Buzzer

• PIN: Connected to D27 of ESP32
• GND: Connected to GND of ESP32

LCD 20x4 I2C

• 5V: Connected to Positive of 5V Battery
• GND: Connected to Negative of 5V Battery
• SCA: Connected to D21 of ESP32
• SCL: Connected to D22 of ESP32

5V Battery

• Positive: Connected to 5V of LCD 20x4 I2C
• Negative: Connected to GND of LCD 20x4 I2C

Code

No code is provided for this circuit.

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This document provides a comprehensive overview of the circuit, including a summary, component list, wiring details, and code documentation. Each component is described in detail, and the wiring connections are clearly outlined to ensure proper assembly and functionality.