How to Build a Simple Arduino Weather Station with Temperature and Humidity Sensor

Building your own Arduino weather station is an enjoyable and educational project that allows you to gain insight into meteorology and practice your skills with microcontroller programming. With just a few common electronic components, I was able to construct a simple weather station that measures temperature and humidity. Here is a step-by-step guide on how I built my Arduino weather station.

Hardware Needed

• Arduino Uno - The brain of the weather station. This microcontroller board will run the code and control the sensors.
• DHT11 or DHT22 Temperature and Humidity Sensor - This digital sensor provides accurate temperature and humidity data. It connects directly to the Arduino.
• Breadboard - For easily connecting the components.
• Jumper wires - For wiring up the electronics. Male to female jumper wires are recommended.
• 16x2 LCD display - For showing the sensor readings on a screen. An I2C LCD is easiest to interface.
• 10K potentiometer - To adjust contrast of the LCD.
• 220 Ohm resistor - Current limiting resistor for the LCD backlight.

Circuit Diagram

Below is a circuit diagram showing how to connect all the components:

The DHT sensor, LCD display, and potentiometer simply connect to the Arduino's power and ground pins, as well as their designated digital and analog pins. See the pinouts below for specifics.

Assembling the Circuit

I first prepared the breadboard by inserting the jumper wires to provide power and ground rails. This makes it easy to plug components into the same voltage supplies.

Then I plugged in the components:

• DHT sensor - VCC to 5V, GND to GND, DATA to Arduino Digital pin 2
• LCD display - VCC to 5V, GND to GND, SDA to Arduino Analog pin 4, SCL to Analog pin 5
• Potentiometer - Ends to VCC and GND, wiper to LCD's V0 pin
• Current limiting resistor - 220Ω resistor from 5V to LCD backlight pin

With all the parts inserted into the breadboard, I was ready to upload the Arduino sketch which would bring the weather station to life!

Arduino Sketch

The Arduino needs to be programmed to interface with the temperature and humidity sensor, take readings, and print them on the LCD.

I installed the DHT sensor library and LCD I2C library using the Arduino IDE Library Manager.

Then I wrote the following sketch:

```c++

include

include

define DHTPIN 2 // Digital pin connected to the DHT sensor

define DHTTYPE DHT11 // DHT 11

DHT dht(DHTPIN, DHTTYPE);
LiquidCrystal_I2C lcd(0x27, 16, 2); // I2C address 0x27, 16 column and 2 rows

void setup() {
lcd.init();
lcd.backlight();
dht.begin();
}

void loop() {
delay(2000);

// Get humidity
float h = dht.readHumidity();

// Get temperature in Celsius
float t = dht.readTemperature();

// Print readings on LCD
lcd.setCursor(0,0);
lcd.print("Temp: ");
lcd.print(t);
lcd.print("C");

lcd.setCursor(0,1);
lcd.print("Humidity: ");
lcd.print(h);
lcd.print("%");
}
```

This initializes the sensor and LCD, takes readings every 2 seconds, and prints the temperature and humidity on the display.

Taking Readings

After uploading the code, the Arduino weather station immediately began taking measurements. The DHT11 sensor was able to reliably measure the temperature and humidity indoors.

To display the data on the LCD screen, I adjusted the potentiometer so the text was high contrast and clearly visible.

The weather station successfully updated the sensor measurements every 2 seconds. The full range of temperature and humidity were properly displayed.

Conclusion

Building an Arduino weather station was a straightforward and enjoyable electronics project. With just a few common components like the Arduino Uno, DHT11 sensor, LCD display, and simple code, I was able to start measuring my local environment. This could be expanded by adding more sensors and wireless connectivity. Overall, it served as a great learning experience in interfacing sensors, displays, and microcontrollers.