The DHT11 is a great sensor to get started with. It's cheap and easy to hook up to an Arduino. It reports temperature and humidity with about 2% accuracy, and this instructable uses a Gameduino 3 as a graphical display, showing 24 hours of history.
What I used
1 Arduino, e.g. Uno
1 Gameduino 3
1 DHT11 temperature/humidity sensor
3 pieces of wire, about 6"
Step 1: Connect the DHT11
DHT11 needs three connections: ground, 5 volt power, and data. I'm using the DHT11 that is included in a cheap 37-in-1 sensor collection. It has the 3 signals clearly marked.
There are a few ways of connecting the DHT11 - here I just jammed the three small wires into the Arduino's sockets.
You can see they're connected to:
- GND (black)
- +5V (red)
- A0 (yellow)
That's all the DHT11 needs - quite minimal. The manufacturer claims that it works fine with wires up to 20 feet long.
Step 2: Connect the Display
Connect the Gameduino to the Arduino, making sure that the pins are all seated correctly.
The Gameduino 3 has a microSD slot, but this application does not use a microSD - so you can leave the slot empty.
Step 3: Install the GD Library and Load the Sketch
Assuming you are already familiar with the Arduino IDE first download the Gameduino library. Installation instructions are at:
You might want to run the "hello world" sample to confirm that the Arduino/Gameduino is working.
Then upload this sketch to the Arduino.
It will immediately connect to the DHT11 and display the current temperature and humidity. As 24 hours pass, the graphs will build up. You can leave the sketch running continuously -- it always shows the temperature/humidity graphs of the last 24 hours.