Adafruit Industries; US $17.50;
This is part of IEEE Spectrum's Special Report on IEEE SPECTRUM'S 2009 Holiday Gift Guide
What better way to introduce a young person to the joys of engineering than by giving a gift that you construct together? I tested four suitable kits. Two are for unusual electronic musical instruments, and two are for dabbling in radio.
The Drawdio turns a pencil—or a pencil sketch—into a musical instrument that sounds something like a kazoo. The kit, available from Adafruit Industries, costs just US $17.50, takes only an hour or so to assemble, and includes everything you need but the AAA battery. If you have any experience soldering components to a printed-circuit board, assembly will be a snap. The hardest step is pushing a thumbtack (included) into the end of a pencil (also included) to make electrical contact with the graphite that runs down its center.
Drawdio is simply an oscillator whose frequency is controlled by the resistance of the circuit path connecting the part of the pencil you grip with the attached thumbtack. You can make sounds by grabbing the pencil in one hand and touching the tack with the other, but that's not the fun way to use it. Instead, draw a heavy line, laying down a lot of conductive graphite as you go. Then press on one end of the line with the forefinger of your free hand while holding the tip of the pencil on the other end of the pencil line. Apply adequate pressure, and Drawdio will emit a low buzz. Moving the tip of the pencil closer to your finger reduces the resistance of the frequency-control path, shifting the sound to a higher pitch. So it's not hard at all to generate a simple tune. If you have trouble hitting the right notes consistently, just mark their positions on the line.
If you really want to impress a musical protégé, splurge on a kit for a theremin, the granddaddy of all electronic musical instruments, whose eerie, melancholy sound is a hallmark of old science-fiction movies.
Moog Music; $359;
Thanks to the late Robert Moog, a pioneer of electronic music, you can buy the Etherwave Theremin kit, available from Moog Music for $359; many online distributors sell it for less. The kit includes a fully assembled printed-circuit board, so all you have to do is wire up the front panel and two antennas, which sense the position of the player's hands, thus controlling pitch (right hand) and volume (left).
The Etherwave kit comes with a handsome oak cabinet, but I was disappointed by the sloppy fit between the top and bottom pieces. Most of my effort went into rebuilding the cabinet. Check your kit and send it back if the woodwork is botched.
That shortcoming aside, this kit is a joy. The theremin, unlike most instruments, has no keys or frets for your fingers to land on. Hitting the right note is quite tricky because you have nothing but your ear and an eyeball estimate of the distance to the pitch antenna to guide you. Like chess or Go, it takes minutes to learn and a lifetime to master. I quickly rendered a recognizable "Mary Had a Little Lamb," all the while chuckling at the notion of playing music without having to touch the instrument. My goal is to master "Over the Rainbow," which should keep me busy for some time yet. Fortunately, the kit's copious documentation includes a video on theremin-playing technique.