Make: Volume 87

3. SNEAKY SPEAKER

A motor has wire coils and magnets inside, and

so does an audio speaker. You can improvise and

use a motor as a makeshift speaker in a pinch!

Cut one end of a ⁄" audio cable (Figure

K

) and

attach its wires to the motor’s wires.

Tape the motor securely to the bottom of a chip

can. Then connect the audio cable plug to a sound

source, like a radio (Figure

L

). Turn the radio

volume up high and you will be able to hear the

radio audio from the can.

How it works: The sound signal is causing the

motor wires to become an electromagnet which

is attracted to the permanent magnets. This

vibrates the motor case and produces sound just