[circuit-bending]  greenarrow.gif (132 bytes)
a bender's guide

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[circuit bending]
[exploring the art]
[how it works]
[direct wiring]
[photo resistors]
[solar cells]
[humidity sensors]
[reset switch]
[line outputs]
[other techniques]
[closing words]

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 up

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, in many cases, 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 areas further away in the circuit for fear of overloading them 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.
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'll notice that when both switches "1" and "2" are turned on at the same time the speaker volume drops or disappears. Or you'll 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 by finding another pair of points to wire one of the switches to. Re-test.

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 new wiring is being charted on the board. 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 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 is a good idea!

It's best to also 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, don't 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.

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