Other Sounds

8.2.2 Other Sounds

In addition to playing musical notes, it is possible to play other sounds. Using the File
Management system, as described in the RobotC On-line Support on the left side-bar under
the ROBOTC Interface ! NXT Brick Menu ! File Management section, it is possible to
place sound les onto the NXT brick for subsequent use during programs. Because of memory
limitations, these sounds must be short (less than a few seconds). To place your own sounds
on the NXT, you must rst nd a sound le in the .wav format. There are many programs
available to convert sound les (like .mp3) to .wav format. A good free program for this
purpose is Audacity. You can use Audacity to clip out a section of a larger sound le and
save it to a .wav format.
RobotC sound les are a special format and have the le extension .rso. Once you have
created the .wav le you are interested in, you must convert it to .rso format. A simple,
free converter program for Windows is here.
Once you have created your custom sound le, copy it to the NXT using the File Manage-
ment window, you can play the sound le from within a program using the PlaySoundFile()
function. Its single argument is the lename of the sound as a string. For example, suppose
you have Homer Simpsons famous \Doh!" in a sound le called doh.rso, then
 
PlaySoundFile ("doh. rso ");
 
will cause your NXT to say \Doh!". This is particularly useful if your robot bumps into a
wall!

// Note Frequencies
const float D5 =587.33;
const float G5 =783.99;
const float F5Sharp =739.99;
const float A5 =880.00;
const float B5 =987.77;
const float C6 =1046.50;
const float D6 =1174.66;
const int BEAT =20; // in 10 Msec
task main () {
// Measure 1
PlayTone (G5 ,2* BEAT );
while ( bSoundActive ){} // wait for tone(s) to finish
wait10Msec ( BEAT );
PlayTone (D5 , BEAT );
PlayTone (G5 ,2* BEAT );
while ( bSoundActive ){} // wait for tone(s) to finish
wait10Msec ( BEAT );
PlayTone (D5 , BEAT );
while ( bSoundActive ){} // wait for tone(s) to finish
// Measure 2
PlayTone (G5 , BEAT );
PlayTone (D5 , BEAT );
PlayTone (G5 , BEAT );
PlayTone (B5 , BEAT );
PlayTone (D6 ,2* BEAT );
while ( bSoundActive ){} // wait for tone(s) to finish
wait10Msec (2* BEAT );
while ( bSoundActive ){} // wait for tone(s) to finish
// Measure 3 and Measure 4 omitted.
}
 
Listing 8.2: This program uses the PlayTone() function to play the opening passage of
Mozart's Eine Kleine Nachtmusik.