Page 159 - Hacking Roomba

140 Part II — Fun Things to Do

When programming with RoombaComm, this means you should not use any of the API
that contains pause() commands. This is actually fine because the only time you’ll find
yourself working in animation mode is when you are dealing with Roomba in real-time and
don’t want your code to just hang out for a few seconds when it should be doing something.
You’ll find in Chapters 8 and 10 that when using Roomba’s sound capability, you normally
will use pause() to wait for the sound to play. In this case you can either use pause() but
set the framerate of your sketch to be slow enough that small pauses do not affect it, or you
can check the time periodically with the millis() Processing function to see when enough
time has elapsed.

Creating Applications with Export
When you have a Processing sketch you like, you may want to share it or even just make it
runnable outside the context of Processing. Normally turning a Java program into an executable
program for a particular operating system is difficult and time consuming. Generating an
executable for three different operating systems is even more difficult. Processing has figured
out all the issues with turning Java programs into applications on Windows, Mac OS X, and
Linux. All that is required of the user is to select File ➪ Export Application, and the current
sketch is converted to three applications, one for each OS. These applications are completely
stand-alone and do not require Processing to run.

When developing your sketch, it’s easy to forget to re-export the applications. When you are fin-
ished and attempt to run the application you just built, you will find that you are running an
older version if you don’t export the application you just built first. Be sure to select Export
Application when done with your sketch.

Normally Processing will also create an applet, but since RoombaComm uses native code via
RXTX, Java applets will not work.

Designing RoombaView

Processing makes graphical interactive programs easy to create, and RoombaComm allows easy
access to controlling Roomba. The two can be combined in a number of ways to create inter-
esting gadgets. The rest of this chapter will focus on creating RoombaView, a program to let
one view graphically the robot’s sensors while it goes about its business or while you control it.

What Features to Include
For RoombaView to be a usable Roomba instrument panel, it should show the main sensors
the robot uses to do its job:

Distance and angle odometry
Bump and cliff sensors state