Making Android Accessories with IOIO

Chapter 3. Bluetooth Temperature Logger

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.

What’s more, we are going to use a USB Bluetooth module attached to the USB port of the IOIO to communicate with your phone wirelessly.

If you don’t want to use Bluetooth for this project, you can just plug the phone into the IOIO in the same way as the project in Chapter 1.

Hardware

In addition to your IOIO, which you should have kitted out with sockets and a power lead in Chapter 1, you will need to buy the items in Table 3-1.

Table 3-1. Parts bin

Quantity	Description	SparkFun SKU	Farnell code	Newark code
1	TMP36	SEN-10988	1438760	19M9015
1	USB Bluetooth adaptor	1848138	39T4089

Figure 3-1. IOIO temperature logger

Almost any USB ...