This project (Figure 3-1) is probably the simplest of the projects in this book. It is very easy to make and there is no soldering to do, other than what you did in Chapter 1 to prepare your IOIO by adding sockets to it.

The temperature sensor itself is a small, 3-pin chip that just plugs into the sockets on the IOIO.

The controlling software takes a temperature reading every 10 seconds and logs it onto the SD card in your phone. It also displays the current temperature in degrees Centigrade or Fahrenheit. When you want to retrieve the data that has been collected, you can just use the USB storage feature of your phone to transfer the file onto your computer. The data is stored in a CSV format so that it can be imported into a spreadsheet.