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You can make the final prop for the user to touch out
of anything conductive. Large-headed pins or nails
are a good option, as is tinfoil (provided it doesn’t
need to be too rugged). Conductive thread or cloth
can make fabric touch-sensitive (but make sure it’s
not against your skin as it’ll always be triggered).
There are a few varieties of conductive paint and ink
that also work. This is where you need to get
creative for the maximum effect.ALTERNATIVE APPROACHES
The Bare Conductive Touch Board is a fantastic
tool for adding sound to projects, but at £53, it’s
not the cheapest option. Adafruit has a few
options under the name Audio FX, and SparkFun
has a similar range under the name Soundie. They
have different options in terms of amount of
memory, method for connecting to speakers, and
types of audio supported, so take a look through
and see which one fits your needs from the
diminutive Audio FX Mini Sound Board – WAV/OGG
Trigger – 2MB Flash for $19.95 that will need an
additional amplifier to connect to speakers. Other
options include audio-out jacks, the ability to play
MP3 files, and more memory. All of these, however,
play audio on a trigger voltage and are not touch-
sensitive. This means that you’ll need buttons to
trigger the sound. Whether or not this will workfor you depends on how you want your effects
to work.
You don’t have to use hardware designed for
sound effects. Many general-purpose
microcontrollers include the hardware necessary
for playing sounds, including the Circuit Playground
Express (CPX). There are details of how to do this
here: hsmag.cc/ZkJzbC. There’s a small built-in
speaker on the CPX, but you can also attach an
external speaker with a bit of wiring.
At the very cheapest end of the spectrum, you
can get electronics designed for toys and greetings
cards from a direct-from-China website. For around
£1 you can usually find a module that plays
predefined sounds (set at the factory), whereas for
around £2 to £3 you can usually get something that
will play a pre-recorded sound (recorded via a
microphone connected to the board). The sound
quality is usually terrible (as you’ve probably heard
on cheap toys and greetings cards), and they can be
a bit tricky to get started, but if you’re on a tight
budget – especially if you plan on making several
objects with integrated sound effects – they can be
worth investigating.ALL YOU HAVE
TO DO IS CREATE
MP3 FILES
The Adafruit Audio FX
Sound Boards are easy to
use, but require buttons
to trigger sounds rather
than touch events