Page 313 - Hacking Roomba

294 Part III — More Complex Interfacing

Listing 13-4 Continued

pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
// ...setup continues as before...
}
void loop() {
updateLEDs();
// ...loop continues as before...
}
void updateLEDs() {
ledi++;
if( ledi < 255 ) {
redVal -= 1; // red down
greenVal -= 1; // green down
} else if( ledi < 255*2 ) {
redVal += 1; // red up
blueVal -= 1; // blue down
} else if( ledi < 255*3 ) {
greenVal += 1; // green up
blueVal += 1; // blue up
} else {
ledi = 0; // reset
}
analogWrite(redPin, redVal); // write brightness vals to
LEDs
analogWrite(greenPin, greenVal);
analogWrite(bluePin, blueVal);
}

Summary

Adding a brain to Roomba is one of the most fun things you can do to it. When you have a
microcontroller on it that you can reprogram and add new sensors and actuators to, the
Roomba becomes a truly interesting robotics platform. Both the Basic Stamp and Arduino
enable you to read and control not only digital transducers like switches and lights, but analog
ones as well. If you’ve looked over the Stamp and Arduino web sites, you’ve no doubt seen
many of the other interesting devices you could hook up to Roomba. Add servos to Roomba to
give it arms, or add microphones to give it ears. Make it come to you when you whistle for it.
The add-on possibilities are limitless.
If you’ve not had much experience with microcontrollers before this, you now know about two
of the friendliest yet most powerful embedded development systems out there. The Basic Stamp
has a great library of tools and techniques developed from over a decade of work by enthusiastic