Day 01
Begineer
Day 27 :- Weather Station
Sept 12, 2026
Completed
Wiring Schematic
Arduino Code
Day 27 Core Training Documentation
Project Overview
The Weather Station project teaches you how to build a professional environmental monitoring system that measures and displays real-time weather data continuously. This project creates a device that tracks atmospheric conditions with precision.
In this project, a DHT11 sensor measures temperature and humidity. An OLED display shows the live readings with formatted text and icons. Arduino continuously updates the display, showing current conditions and tracking environmental changes.
When the station powers up, the OLED display shows welcome information. As the DHT11 begins taking measurements, temperature and humidity values appear on the display. The weather station continuously updates every few seconds, showing real-time environmental changes.
This project teaches Environmental Sensing, Data Integration, Real-Time Display Updates, Weather Data Formatting, and Professional Monitoring Systems.
By finishing this project, you’ll know how weather stations work in meteorological applications, agricultural automation, and environmental monitoring networks.
Components Required
To build this circuit, collect these specific items from your kit:
Arduino Uno × 1, Breadboard × 1, DHT11 Temperature and Humidity Sensor × 1, OLED Display 128×64 (I2C) × 1, 10kΩ Resistor × 1, Jumper Wires × 6, USB Cable × 1
Circuit Connections
Step 1: Connect Ground Rail
Connect the Arduino GND pin to the negative rail of the breadboard. This creates a shared ground connection for all weather station components and sensors.
Step 2: Connect OLED VCC
Connect the VCC pin of the OLED display to Arduino 5V. This provides power to the display module for continuous operation and real-time updates.
Step 3: Connect OLED GND
Connect the GND pin of the OLED display to the breadboard negative rail. This completes the display power circuit and establishes ground reference.
Step 4: Connect OLED SDA Pin
Connect the SDA (data) pin of the OLED to Arduino Pin A4. This carries data signals to the display using I2C protocol for communication.
Step 5: Connect OLED SCL Pin
Connect the SCL (clock) pin of the OLED to Arduino Pin A5. This provides timing signals for I2C communication with the display module.
Step 6: Connect DHT11 Sensor
Connect DHT11 VCC to Arduino 5V. Connect DHT11 GND to breadboard GND. Connect DHT11 DATA to Arduino Pin 7 for temperature and humidity measurement.
Step 7: Connect Pull-Up Resistor
Connect one end of the 10kΩ resistor to Arduino Pin 7 and the other end to Arduino 5V. This stabilizes the DHT11 data signal for reliable operation.
Step 8: Verify Connections
Check OLED I2C connections and DHT11 sensor connections before uploading your code. Ensure all power and ground connections are secure and properly seated.
Important: The OLED display requires proper I2C address configuration. Most displays use 0x3C, but verify your specific module if it does not display anything.
How the Arduino Code Works
Initialize Display and Sensor
In setup(), Arduino initializes the OLED display library with the correct I2C address. The DHT11 sensor library is initialized to begin reading temperature and humidity data.
Configure Display Layout
The OLED display size is set to 128 pixels wide by 64 pixels high. Text size is configured for readability. The display is turned on with full brightness for visibility.
Read Temperature and Humidity
Inside the main loop, Arduino reads temperature using dht.readTemperature() and humidity using dht.readHumidity(). These functions communicate with the DHT11 sensor to retrieve current measurements.
Check Data Validity
The program verifies that sensor readings are valid before displaying them. If the sensor fails to read, an error message is displayed instead of false data.
Format Display Information
The OLED library functions draw text, numbers, and graphics at specific locations. Information is organized with temperature at the top, humidity below, and weather status indicators displayed.
Expected Output
After uploading your code, here is what happens.
After uploading your code, the OLED display illuminates with the weather station title. Temperature reading appears in large digits showing current temperature in Celsius. Humidity percentage displays below with real-time updates every two seconds.
Operational Troubleshooting
OLED Display Shows Nothing :- Verify the I2C address in your code matches the display module. Check that SDA connects to Pin A4 and SCL connects to Pin A5. Confirm VCC and GND have proper power connections.
Temperature and Humidity Show Zero :- Verify the DHT11 connects to Pin 7 and check the pull-up resistor connection. Ensure the DHT11 library is installed and imported correctly in your Arduino IDE.
Text Appears Garbled or Incomplete :- Verify the display size in your code matches your OLED module specifications. Check text positioning and size settings. Ensure the OLED library version is compatible.
Sensor Data Does Not Update :- Increase the delay between measurements to at least two seconds minimum. Verify the sensor is receiving proper power and data line connection. Move the sensor away from heat sources.
What You Learned
By finishing this project, you now know :-
How environmental sensors provide real-time data for monitoring. You understand how I2C protocol enables device communication effectively. You learned to integrate multiple sensors and displays into one system. You mastered formatting and visualizing complex environmental data clearly. You developed skills for building professional monitoring systems and applications.
Next Lesson
In Day 28, you’ll learn how to create a Smart Home Automation system that controls lights, fans, and appliances based on sensor inputs and user commands. You will build an integrated control system.