It's now time to test our project. First, we'll do some configuration in Google Docs. Create a new spreadsheet in Google Docs, name it (I named mine "Yun"), and set the title of each columns in the first row, like the picture below:

Finally, you are ready to test the project. Upload the code to the Arduino Yun board, open the Google Docs spreadsheet in your browser again, and wait a moment. After a while, the first measurement should appear:

I also used the built-in plotting functions of Google Docs to plot my data as it comes in. For example, I used the simple "Line" chart type to plot the light level. This is the result over some hours in the morning, showing that the light level is slowly rising:

And over the same period of time, I plotted the evolution of the temperature & humidity:

The really nice thing about this is that it is updated automatically as data comes in, and it can be accessed from anywhere: you just need your Google username & password!

You just learned in this project how to send measurements from your Arduino Yun board to Google Docs, so this data can be accessed from anywhere. You also saw how to build automated email alerts based on the data in your home. You can of course improve this project in many ways. The first one is to add more sensors to the project, for example a wind speed sensor or a smoke sensor. You could even add an USB camera to store pictures on an SD card, using the Yun SD card reader.

You can of course use many Arduino Yun boards, for example in different parts of your home. You can also customise the email alert part: you can build more complex alerts based on the measured data, or set the project to email you the sensor data at a regular time interval. If you have other ideas to improve this project, please share!