The next day, Silver took the circuit to the summer camp where he taught and showed the campers how it worked. When it came in contact with conductive objects, they acted as extensions of the device: Users could touch the object to create different sounds, like pressing the keys on a keyboard. Silver’s campers tested it out, making music with everything from apples to bicycles. Later, a co-worker suggested that Silver hook up the circuit to a pencil, since electricity can pass through its graphite core. The result was Drawdio, a pencil that plays “music” when you draw. Silver published instructions for Drawdio online, and he loves when people use his idea to create something new. With that in mind, Popular Science built a caroling candy cane—and so can you. This article was originally published in the December 2015 issue of Popular Science, under the title “Make Sweet Holiday Music.”
WARNING: Don’t get milk—or any other liquids—on the circuit or battery.
Stats
Time: 2 hoursCost: $55Difficulty: Medium
Tools
Utility knifeWire stripperSoldering ironScissors
Materials
We purchased these materials from Jameco Electronics, Home Depot, and a local grocery store.
PerfboardTLC555CP LinCMOS timer, eight- pin DIP1⁄4-watt resistors, 5% (10, 10K, 10M, 270K ohm)0.1 uF, 50-volt, 20% ceramic disc capacitor100 uF, 35-volt, 20% radial capacitor820 pF ceramic disc capacitorPNP general-purpose amplifier, 2N390622 AWG hook-up wire in red, black, and green2 x AAA battery clipMini speaker with wire leadsDouble-sided foam tape2 AAA batteriesCandy caneAluminum foilElectrical tape
