Projects photo
SHARE

In 2007, electrical engineer Jay Silver discovered how to turn anything into a musical instrument. While tinkering with an electronic-organ kit, he accidentally spilled lentils on the kit’s circuit, which produces musical notes. “As I was trying to dry it out,” he says, “I noticed the noise was changing.” He realized that touching the device shifted the sound.

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 hours
  • Cost: $55
  • Difficulty: Medium

Tools

  • Utility knife
  • Wire stripper
  • Soldering iron
  • Scissors

Materials

We purchased these materials from Jameco Electronics, Home Depot, and a local grocery store.

  • Perfboard
  • TLC555CP LinCMOS timer, eight- pin DIP
  • 1⁄4-watt resistors, 5% (10, 10K, 10M, 270K ohm)
  • 0.1 uF, 50-volt, 20% ceramic disc capacitor
  • 100 uF, 35-volt, 20% radial capacitor
  • 820 pF ceramic disc capacitor
  • PNP general-purpose amplifier, 2N3906
  • 22 AWG hook-up wire in red, black, and green
  • 2 x AAA battery clip
  • Mini speaker with wire leads
  • Double-sided foam tape
  • 2 AAA batteries
  • Candy cane
  • Aluminum foil
  • Electrical tape

Instructions

Cut your perfboard

1. Cut your perfboard

Using a utility knife, cut your perfboard into a rectangle with five rows of 23 holes. Label the rows A-E (top to bottom), and the columns 1-23 (left to right).
Add the timer

2. Add the timer

Insert the TLC-555CP timer with the upper left corner at A16 and lower right corner at D19. Bend the timer’s legs out underneath the perfboard to keep it in place.
Add resistors, capacitors, and amplifier

3. Add resistors, capacitors, and amplifier

Stick the resistors, capacitors, and 2N3906 amplifier in the perfboard as follows. You can put a foam block beneath the board to hold the pins.
Add jumper wires

4. Add jumper wires

Use a red jumper wire to connect A12 to D15, a black jumper wire to connect A15 to E19, and a red jumper wire to connect A13 to A20. (NOTE: In this photo and the ones after, the 10KΩ resistor is shown in the wrong spot. It should be one column over to the left, at A21 to B21.)
Add candy cane leads, battery clip, and speaker

5. Add candy cane leads, battery clip, and speaker

Solder

6. Solder

Remove everything from the board except the timer. Solder a jumper between the timer’s legs at B16 and C19. Then insert the other components in the same order you did before. Solder their leads together under the perfboard, as shown. When you’re done, use double-stick foam tape to attach the speaker to the top of the perfboard. (NOTE: Because the circuit is flipped over, the rows now run A-E from bottom to top. The columns still run 1-23 from left to right.)
Test your circuit

7. Test your circuit

Insert batteries and touch the exposed green leads with your hands. The speaker should emit a tone that changes pitch based on the resistance between the green leads. In other words, moving your hands should alter the sound.
Attach circuit to candy cane

8. Attach circuit to candy cane

Use double-sided tape to attach the perfboard and battery clip to the candy cane. If you plan to reuse the circuit, just wind electrical tape around the unit to hold it in place.
Complete the candy cane

9. Complete the candy cane

Coil the short green lead up the hook of the candy cane and the long green lead down the candy cane’s body. Wrap a band of aluminum foil around each lead and tape closed.
Make music!

10. Make music!

Grip the candy cane with one hand, touching the wire around its body, and lick near the wire up top. You can also try dipping the candy cane into a mug of hot chocolate, making sure to keep the circuit dry, and drinking from the mug with a straw. Or stick one finger in some water on a saucer, and make patterns in the liquid while holding the candy cane in your other hand.
Projects
sound