MATERIALS
9V Recording Module, RadioShack part
#276-1323. This is a pre-wired record/playback
unit complete with audio board, speaker,
and controls that will record up to 20 seconds
of sound in nonvolatile memory. There are
actually 2 different versions of this part;
try to find the one with the separate wired
microphone. It’s much better, with a louder
and clearer sound!
9-volt battery
Clothespin serves as a spring-loaded booby trap
and as the switch that triggers the sound
Rubber band
Aluminum duct tape
Wire
Plastic cap from 1gal milk jug
Super glue aka cyanoacrylate glue
Zip ties
Double-sided foam tape
Soldering iron, solder
Wire cutters
Small bit of brass strip (optional)
with tiny screws ( 2)
Drill (optional)
Plastic cap
Speaker (from module)
Module circuit board
Record button
Double-sided
foam tape
9-volt battery
Brass strip
Rubber band
Play wire 1
Play wire 2
Aluminum duct tape
Clothespin
Illustrations by Bob Knetzger
BUILDING THE BOOBY TRAP
1. Disassemble the clothespin — the wire spring
is too stiff for our purpose. Reassemble the pin as
shown in Figure A (next page) so that the spring is
used as a fulcrum pivot. Wrap a rubber band around
the jaws of the clip a couple of times. Slide the
rubber band closer or farther from the fulcrum to
adjust the tension. The clip should open easily, but
still be able to close all the way.
For an easier-to-use booby trap, add an optional
extension to the top leg of the clothespin. Bend
a small strip of stiff brass so that it lies flat when
Make: 61
