In 1921, two scientists made the first modern loudspeaker out of magnets, wire, and paper. Now manufacturers use synthetic fibers and even ferrofluid. Why stop there? Your kitchen contains plenty of materials to build a functional woofer. A potato chip works as a sound-emitting diaphragm here, but other rigid foods work just as well.
Time: 5 to 10 minutes
Cost: A few bucks
1) Gather the parts
25 feet of 30-gauge magnet wire
Two ¾-inch-diameter-by-¼-inch cylindrical refrigerator magnets
Two cardboard strips, ½ inch by 1.5 inches
A wooden cutting board or piece of particleboard
One 6-inch-long, ¾-inch-diameter dowel
A hot-glue gun
Potato chips (thick-cut chips work best)
2) Build a voice coil
Wrap the magnet wire tightly around the dowel to make a ⅜-inch-tall coil, leaving 12 inches of wire on each end. Smear the coil with hot glue, let it cool, and slide the coil off the dowel. Sand an inch of paint off the wire’s ends.
3) Assemble the speaker
Fold the cardboard strips into a Z shape. Hot-glue the magnets and strips to the particleboard, and then the coil to a chip. Next, glue a cardboard strip to each end of the chip while centering the coil over the magnet.
4) Rock out
Connect the sanded speaker wires to an amplified audio source, such as a home entertainment center (a portable player may lack enough power), and listen to the saltiest, crispiest music you’ve ever played.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.