Circuit Documentation

Summary

The circuit in question is designed to monitor air quality using an MQ-135 sensor and control two exhaust fans based on the sensor readings. The core of the circuit is an ESP32 microcontroller, which interfaces with the MQ-135 sensor, a DHT22 temperature and humidity sensor, and a TFT LCD display for output. The ESP32 also controls a 2-channel relay module that powers the exhaust fans. The circuit is powered by a 240V power source, with the ESP32 and other low-voltage components receiving regulated power from the source.

Component List

ESP32 (30 pin)

• Description: A microcontroller with 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

DHT22

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

TFT LCD Display ST7735S

• Description: A small LCD display for visual output.
• Pins: Vcc, GND, CS, RESET, A0, SDA, SCK, LED

MQ-135 SENSOR AIR QUALITY

• Description: A sensor for detecting a wide range of gases, including NH3, NOx, alcohol, benzene, smoke, and CO2.
• Pins: VCC, GND, A0, D0

Relay Module 2 Channel

• Description: A module with two relays to control high power devices.
• Pins: GND, IN1, IN2, VCC, NC1, COM, NO1, NC2, NO2

Exhaust Fan 12"

• Description: A 12-inch exhaust fan for ventilation.
• Pins: Live, Neutral

240v Power Source

• Description: The main power source for the circuit.
• Pins: Live, Neutral

Wiring Details

ESP32 (30 pin)

• GND connected to common ground.
• Vin connected to VCC of Relay Module, MQ-135 Sensor, and TFT LCD Display.
• D35 connected to A0 of MQ-135 Sensor.
• D32 connected to IN1 of Relay Module.
• D33 connected to IN2 of Relay Module.
• D23 connected to SDA of TFT LCD Display.
• D19 connected to DAT of DHT22.
• D18 connected to SCK of TFT LCD Display.
• D5 connected to CS of TFT LCD Display.
• TX2 connected to A0 of TFT LCD Display.
• RX2 connected to RESET of TFT LCD Display.
• 3V3 connected to VCC of DHT22 and LED of TFT LCD Display.

DHT22

• GND connected to common ground.
• VCC connected to 3V3 of ESP32.
• DAT connected to D19 of ESP32.

TFT LCD Display ST7735S

• GND connected to common ground.
• Vcc connected to Vin of ESP32.
• CS connected to D5 of ESP32.
• RESET connected to RX2 of ESP32.
• A0 connected to TX2 of ESP32.
• SDA connected to D23 of ESP32.
• SCK connected to D18 of ESP32.
• LED connected to 3V3 of ESP32.

MQ-135 SENSOR AIR QUALITY

• GND connected to common ground.
• VCC connected to Vin of ESP32.
• A0 connected to D35 of ESP32.

Relay Module 2 Channel

• GND connected to common ground.
• IN1 connected to D32 of ESP32.
• IN2 connected to D33 of ESP32.
• VCC connected to Vin of ESP32.
• COM connected to Live of 240v Power Source.
• NO1 connected to Live of Exhaust Fan 12" (Instance 1).
• NO2 connected to Live of Exhaust Fan 12" (Instance 2).

Exhaust Fan 12" (Instance 1)

• Live connected to NO1 of Relay Module.
• Neutral connected to Neutral of 240v Power Source.

Exhaust Fan 12" (Instance 2)

• Live connected to NO2 of Relay Module.
• Neutral connected to Neutral of 240v Power Source.

240v Power Source

• Live connected to COM of Relay Module.
• Neutral connected to Neutral of both Exhaust Fans.

Documented Code

No code has been provided for the microcontrollers in the circuit. The documentation of the code would typically include a description of the functionality, setup, and main loop, along with any functions or libraries used. Since no code is available, this section cannot be completed.