SPY TECH
A B
CD
TO PINCH A THIEF: Fig. A: Take apart and reassemble
a clothespin. Fig. B: Add an optional brass extension to
the clothespin.
the clothespin is held open. Drill 2 small holes in
the brass and attach it to the clothespin with tiny
screws (Figure B).
2. Wrap the jaws of the clothespin with the aluminum tape. Poke a small hole in the aluminum and
attach the stripped end of a short wire (about 5"
long) to each jaw. Twist the wire and crimp the tape
over it firmly to make a good electrical connection
(Figure C). You’ll be soldering the other ends of
these 2 wires to traces on the recording module’s
circuit board.
3. Install the 9-volt battery and test the circuit:
press and hold the Record button (the red LED goes
on) and speak loudly into the microphone. Release
the Record button when finished. Press the gray
button on the PC board to hear your recording.
You can improve the sound significantly and
protect the naked speaker by adding a resonant
chamber/cover. Use a plastic bottle cap from
a gallon milk jug — it’s just the right diameter.
Super-glue it to the front of the speaker (Figure D).
62 Make: Volume 16
Fig C: Metal tape on the ends of the clothespin serves
as contacts for the spring-loaded switch. Fig. D: A small
plastic cap improves the speaker’s sound.
4. Now modify the circuit to wire up the clothespin.
Remove the battery. Find the gray rubber-domed
Play switch on the PC board (Figure E). Bend the
3 metal tabs on the back and remove the button.
5. Feed a wire from the clothespin jaw through 1 of
the tab holes and over the edge of 1 of the 2 switch
traces. Carefully solder the wire to the first trace
only — don’t short out the traces! Do the same
thing for the second jaw wire and solder it to the
second trace (Figure F).
Now the clothespin will act as a Play switch: when
the jaws touch together, the sound plays. Try it! To
prevent the sound from playing, place a slip of paper
between the jaws as an insulator.
6. To finish, stick the battery to the top of the
clothespin with double-stick foam tape, and then
stick it to the circuit board with more foam tape.
Foam-tape the speaker on top, then use cable ties
through the center of the spring to cinch everything
together. Tuck in the microphone and Record switch
wires to neaten it all up (Figures G and H).
Photography by Bob Knetzger
