IF THIS BOOK HAD EARS: Your sister might
be listening to everything you’re saying!
Miniature “amplified listener” I used RadioShack
#33-1096; the Listen Up (“As Seen On TV”)
Small wireless FM transmitter I used the Accurian
T707, RadioShack #12-2054.
Personal music player with FM receiver I used an
old Walkman-style cassette player.
Earbuds or headset
AA batteries ( 2)
2x AA battery holder
Hookup wire, red and black, around 22 gauge
Heavy shirt cardboard or illustration board
Photograph by David Simpson
Alligator jumper cables
Binder clips, large ( 1–2)
Drill and ½" drill bits
Paint brush, about ½" wide
Wood boards ( 2), with drywall screws ( 4) or
handscrew clamps ( 2) for use as a book press
TESTING, ONE, TWO, THREE
Let’s launch this mission. First, we’ll test everything.
Plug the headphones into the listener and turn it on.
You should hear your surroundings like a bat.
Now plug the headphones into the FM receiver
and tune it to a static-only spot at the low end of the
dial, where these wireless FM transmitters generally
Plug the transmitter into the listener, tune it to
match the receiver, and you should be able to hear
the sounds of the listener through the receiver. The
signal should be strong, but it still might have some
Have a co-conspirator help with your test by talking near the listener while you walk away, listening
through the receiver. See how far you can get before
the signal is no longer intelligible. (For the best
range, make sure to use fresh batteries.)
Test the components individually and together
like this after each step of the assembly process.
Delicate wires can snap and tiny switches can get
switched at any stage, making troubleshooting