Talk to the Animals
How to Create Custom Sound Effects for NXT Robots.
NOTE: Note to parents and teachers: This process requires downloading software from the Internet and may
require adult supervision.
An animal is just not complete without animal sounds. Granted, not all of the animals in this book are known
for their sounds. Still, for those animals that are, the addition of sound just makes for a better robot.
Take the elephant robot, for example. Have you ever heard of a quiet elephant? A silent elephant is not only
unexciting, it’s unrealistic. But a trumpeting elephant; now that is a real challenge for NXT builders.
As we work our way through the process of creating custom sound effects for the NXT, it may be necessary
for you to download some free software. (Freeware is software that can be legally down loaded from the Web
and used.) I’ll give directions for this as we progress.
A Source for Sound Effects
Now I could create my own custom sounds, but it’s a whole lot easier to spend about 99 cents on an elephant
trumpeting sound from iTunes. If you do not have iTunes on your computer, you can download it for free from
the Apple website at http://www.apple.com/itunes/.
Once you have iTunes installed, open it and search for “elephant sounds” (or whatever animal you are creating
sounds for). Once you’ve found the sound you want and are ready to download the audio file, the purchase can
be completed with a credit card or Pay Pal.
Converting Your iTunes File
The sounds found on your NXT brick are .rso files. In fact, .rso is the only audio format the NXT can read. (File
extensions like, .jpg, .doc, .wav and .rso tell a computer what program it should call on to open or use that file.)
What follows is a description of how you can convert an iTunes sound file to the .rso format so we can add
our customized sound to the elephant.
The first step is to create a playlist of the audio files we want to convert, then use iTunes to burn the audio files
to a CD. Here’s the procedure:
1. Open iTunes.