Abstract :
Many years ago in the offices here at IEEE Spectrum, we had a "Wheel of Excuse" pinned to the outside wall of a cubicle. Made from paper and cardboard in the style of a small lottery wheel, it could be spun to suggest plausible excuses to luckless editors seeking to explain a blown deadline. The wheel had its limitations, however, chief among them being the small number of excuses that could be squeezed onto a disk just 25 centimeters across, and a tendency to fall off the wall if spun with too much vigor or desperation. · Spectrum\´s offices were renovated this year, the dingy cubicle walls swept away for a modern office layout. So I thought it might be time for an updated Wheel of Excuses–a digital one, naturally. I wanted a one-touch system that would show an animation of a spinning wheel, followed by the display of a randomly selected excuse from an extended list. · Initially, I thought I would make the new wheel using an Arduino and a touch-screen add-on shield. But the speed at which graphics could be drawn on the touch screen proved too slow for the kind of animation I wanted, and the 2.8-inch screen was on the small side in any case. · So I turned to the US $35 Raspberry Pi microcomputer, which had the final release of its first generation in July–the Model B+. Among other changes, the Model B+ has two more USB ports than the Model B along with an expanded general-purpose input/output (GPIO) connector, and it relies more heavily on HDMI for video output.
