Along with protecting yourself
and the components you add to the circuit as you bend it, there are
precautions to take that will protect the circuit itself. If you're
working with a rare or hard to replace circuit, take heed...
During the exploration process using the
test lead to search the circuit for bending points, apply the traveling
screwdriver's tip to the various circuit points tested very briefly
-- just for a moment. In this moment beware of the following conditions.
Don't try the
connection again if you observe:
- a spark
- a dimming of electronic
displays or lights
- a "pop" from the speaker
- a volume decrease
or failure of the sound in progress
- a humming in the speaker
- a component heating
up on the board
- batteries heating
As electricity flows its course through
a circuit, the resistance of circuit components often reduces the voltages
in the circuit "down stream" of the power supply. These components are
meant to operate on these diminished voltages rather than the full voltage
of the batteries. Due to this, it's best not to jump the battery voltage
into the further away areas of the circuit with your test leads for
fear of overloading these components and causing the conditions listed
above. Essentially, this means to avoid the area where the battery power
enters the circuit board during your initial explorations with the screwdriver/test
lead apparatus. Always exercise caution while near the power-supply
section of the board.
Another important fact to remember is
that while individual new circuit-bending paths may have no adverse
effect upon the circuit when they are switched on by themselves, such
paths in combination with each other might not be so forgiving. In other
words, switch "1" let's say, which activates your first discovered pair
of circuit-bending points, adds a nice warble effect to the instrument's
voice and works just fine when turned on by itself. Switch "2", which
activates your 2nd circuit-bending connection, adds unpredictable pulsing
to the instrument's voice and works just fine when turned on by itself.
But you notice that when both switches "1" and "2" are turned on at
the same time the speaker volume drops or disappears. Or you notice
another of the above trouble signs.
As mentioned previously, eccentric circuitry
can cause a crash. Battery supply interruption may be needed to reset
and safeguard the circuit. This is an important consideration; be sure
to install a RESET SWITCH as described toward the end of the EXPLORING
THE ART section, above, in any instrument prone to crash.
The reality is that the new wiring of
circuit-bending is compounded in many convoluted ways as the different
controls are combined with each other. This may cause trouble. Be aware
of such switching combinations; avoid them or modify the wiring behind
them (i.e., find another pair of points to wire one of the switches
On the other hand, this chaotic snowballing
of creative short-circuiting is at the essential and surreal heart of
this chance process. There is no way to experience all the switching
combinations as the wiring is being charted on the board, or while the
tests are being made to decide where the new wiring will go. It is not
until the instrument is complete that it can be fully explored by the
designer, since it is not until then that all discovered connections
and new controls are in place at once and can be combined. At that point
magic occurs. The alien instrument is explored, revealing itself in
ways never evident during the initial, one-effect-at-a-time, discovery
process. This is a wonderful moment.
But to the point: good circuit-bending
connections create unusual audio behavior without taxing the circuit,
without draining power and without any destructive effect upon the electronics
at all. Feeling the integrated circuits, resistors and other components
on the circuit board while bending is a very good idea.
If a connection is made that causes a component to become unusually
hot (some components will warm up a bit normally), avoiding that connection
might be a good idea!
It's best to avoid using AC adapters to
power circuit-bent instruments. This is because such power converters
are known to add noise to circuits as well as damage electronics due
to poor voltage regulation and inadequate surge suppression. Use high-quality
rechargeable batteries with back-ups.
Along the course of circuit-bending some
circuits will be destroyed. As a general rule, never try to circuit-bend
anything you can't live without. Experience, however, will lead to more
successes than failures, and in time a fascinating collection of instruments
will come about.