Arduino-Based CO2, Temperature, and Humidity Monitoring System with OLED Display

This project monitors CO2 levels, temperature, and humidity using the SCD4x sensor and presents the data on an SSD1306 OLED display in real time.

Hardware Requirements

• Arduino Board (e.g., Arduino Leonardo, Arduino Micro or similar with ATmega32U4 Processor)
• SCD4x Sensor (SCD41/SCD40)
• SSD1306 0.91inch OLED Display Module (128x32 pixels, I2C interface)
• Jumper Wires

Pinout Details

SCD4x Sensor Pinout

Pin	Connection
VCC	5V
GND	GND
SDA	Pin 2
SCL	Pin 3

SSD1306 OLED Display Pinout

Pin	Connection
VCC	5V
GND	GND
SDA	Pin 2
SCL	Pin 3

Note: Both the SSD1306 OLED and the SCD4x sensor communicate over I2C, so they share the SDA and SCL lines.

Libraries Required

These libraries can be installed via the Arduino Library Manager:

• Adafruit GFX - Graphics library for the OLED display.
• Adafruit SSD1306 - OLED display driver.
• SparkFun SCD4x Arduino Library - For reading data from the SCD4x sensor.

Software Setup

1. Open the Arduino IDE.
2. Go to Sketch > Include Library > Manage Libraries.
3. Install the required libraries (Adafruit GFX, Adafruit SSD1306, and SparkFun SCD4x).
4. Connect the hardware according to the pinout.
5. Upload the code to your Arduino.

Example Output (on Serial Monitor)

CO2 (ppm): 413.00    Temperature (°C): 22.3    Humidity (%RH): 55.6
CO2 (ppm): 420.00    Temperature (°C): 22.3    Humidity (%RH): 55.4
CO2 (ppm): 425.00    Temperature (°C): 22.3    Humidity (%RH): 55.3

Example Display Output

CO2 (ppm): 413.00
Temp (°C): 22.3
Humidity (%): 55.6

License

This project is licensed under the MIT License. See the LICENSE file for details.