FIGURE D

The fast-build PPRK uses a stamped aluminum chassis. Click picture for a larger image.

One critical ingredient of the PPRK is the SV203 module. This tiny board, made by Pontech, Inc. (at http://www.pontech.com), communicates with any processor using a serial port, providing up to five analog inputs (three of which we use for the range sensors) and up to eight hobby servos (three of which are used to control the wheels). We imagine that many new roboticists, after building a PPRK, will make use of the SV203's full capabilities to create more intricate and customized robots. We're waiting for pictures from the first person to build a PPRK and attach a robot finger to the chassis, so that it can actually type on a desktop computer keyboard. Another interesting, if twisted, idea is to design a PPRK that can position itself under a stylus hanging from the ceiling and write on itself. We leave that as an exercise to the reader with an overwhelming excess of free time.

I built one; now what?
Once you've built a PPRK, what next? The fact that the robot has sensors means that it can do much more than just execute canned motions. You can program it using our CodeWarrior interface or any of several other Palm development environments to respond to sensor values in intelligent ways. As examples, our downloadable software includes a wandering program that moves omni-directionally away from the closest obstacle. Coral the robot completely, and it will begin rotating in place, scanning with its range sensors for the first opening through which to plot its escape.

We also provide a left-wall-following program. Like a rat in a maze, the PPRK will explore its environment, always keeping a wall on its left when possible. One undergraduate visitor from the University of Michigan even created navigation architecture for PPRK. As it left-wall-follows in its environment, the robot keeps track of concave and convex corners that it negotiates. By naming these corners and pointing to them on the screen, you can ask the robot to return to an earlier location. This project, although definitely a work in progress, is available for download as well and demonstrates the potential that this platform has as a serious robotics research test-bed.

Once you've used our existing programs, you'll be ready to program the PalmPilot Robot Kit yourself. The process is simple: create robot software on a PC intended for download to the Palm device. Once the software is complete, you can compile it and even run a Palm simulation to check your graphical user interface. Finally, you can download your new application to the Palm device and execute it. Writing code for the PalmPilot Robot Kit is just like writing code for Palm applications in general; the difference is only that the code you write for the robot happens to communicate with the robot's SV203, motors, and sensors via the Palm device's serial port.

Specifically, we use the Metrowerks' CodeWarrior environment to write C++ code for PPRK. CodeWarrior is particularly useful for debugging and for building effective user interfaces for the robot. But you can also use a variety of other compilers designed for the Palm device, including the free GNU C compiler. Figure E shows a screen shot of the Metrowerks environment during program development.