Get bent!

An adventure in circuit bending

In 1979 when I was a grad student at Brandeis, I had a summer job in the university mail room. One day at work I found a copy of Popular Electronics magazine that had been delivered to campus after its rightful owner had fled for the season, and I absconded with it. My karmic come-uppance for that act of theft was swift and cruelly appropriate: I was transformed into a techno-zombie addicted to solder fumes and electronics surplus. Over the next quarter-century I built lots of gizmos, some of them marginally useful, although practicality was never the point of my hobby; for me, the thrill of assembling circuits resided in the magic of bringing inert copper and silicon to life, flashing, beeping, buzzing, and talking robot-talk. While many of my projects were designed with real-world tasks in mind (e.g. music synthesis and audio processing), some were intentionally useless and/or willfully annoying: a plastic bust of Beethoven fitted with red LED eyeballs and an electro-mechanical buzzer; a pointlessly, painfully loud solid-state siren; and an FM radio signal-jammer designed for covert use at the beach or by the pool (a device of arguably practical, if ethically questionable, application). When I moved to New York I put the hobby aside, reasoning that I could not afford to squander cash, time, and mental focus in a hostile urban environment. But no person can repress his or her inner sociopath forever, and eventually I drifted back to pimply geekdom via "circuit bending," i.e. the black art of mutilating commercial electronic devices in order to generate nasty and unpredictable noise. Toys such as discarded electronic games, defective music keyboards, and offensively cute stuffed animals equipped with speech circuits are a favorite target of circuit benders. Most bending projects I've seen and heard are executed with exquisite finesse, the modified or "bent" electronic guts either transplanted into shiny new housings, or the hacked circuit kept in its original housing, repurposing the toy's original raison d'etre as child-targeted commodity (Hear Furby squawk and screech. Furby is having a mental breakdown. Furby wants to die, and Furby intends to take you and everything you love with him.).

While it's possible to expend significant amounts of cash on a bending project by purchasing new components, it's economically and aesthetically appealing to go lo-tech, incorporating recycled electronic and mechanical detritus. The concept of elegance, of deriving maximum effect from minimum design complexity, is also highly valued. I was able to realize both of these ideals in my first (and so far, only) completed circuit bend, a mutated speech circuit extracted from a Mighty Morphin Power Rangers doll that belonged to one of my kids eons ago.

The box resided in the belly of the stuffed superhero, and when you squeezed his squishy pupik, he'd bellow, in sequence, one of three pre-programmed phrases: "Ah! Ooh! Ooh-ah!; C'mon guys, it's Morphin time; Tyrannosaurus!"

Examining the circuit board, I realized that I couldn't do anything too radical to alter the speech output. The three spoken phrases are permanently encoded in a chip mounted on the board, and reprogramming the device to say something different would be impossible. But I figured that it might be possible to change the speed and pitch of the speech output; designs like this use what's called a clock circuit to pump out speech data, and I started fiddling with the board to figure out which components set clock speed.

"Fiddling" is the operative concept in circuit bending wherein lies its democratic appeal. No mastery of electronics theory is required, you just pick up a wire, start probing, and observe what happens. (It should be emphasized that this approach is restricted to low-voltage, battery-operated devices; the worst that can happen in such a situation is that delicate circuit components gets zapped, with no harm to the experimenter. Lethal encounters with 120VAC-operated devices are highly discouraged.) Not only is mastery of theory not required, theoretical prowess might actually inhibit creativity. The grungy, random audio sputterings prized by circuit benders are precisely the effects that engineers do their professional best to avoid. By way of example, one popular bending technique is voltage-starvation, i.e. feeding a circuit with a supply voltage less than that for which it is optimally designed, forcing components into erratic behavior. From the standpoint of orthodox circuit design this is suicidal behavior, but the bender's approach challenges us to acknowledge that what's considered "useful" is an arbitrary slice from a continuum of physical possibility: the characteristics of semiconductors vary over changing voltage and temperature conditions, and although ICs and transistors are manufactured to operate predictably within a specified range, operating them out of spec isn't a violation of their nature, it is an expression of that nature. (There's a metaphor in there about human behavior, but I don't feel like parsing it out right now.)

I digress. I quickly discovered that a 1 mega-ohm resistor on the circuit board set the clock speed, so my initial plan was to replace that fixed resistor with a variable resistor (a.k.a potentiometer, commonly referred to as a "volume control") so I could make the box talk crazy by fiddling with a knob. Then I accidentally discovered that my fingers alone made a perfectly functional variable resistor (see Wikipedia, Galvanic Skin Response), which made the replacement component unnecessary. Talk about design elegance: I was able to vary the response of the circuit in complex fashion with zero hardware investment. I de-soldered the 1 mega-ohm resistor from the circuit board, soldered wires to the two vacated lead holes in the board, and attached the ends of those wires to metal screws mounted on the plastic housing of the device. By squeezing the heads of the screws while pushing the play button, I transformed Bandai America Inc.'s exploitation of delusional power fantasies in children into a banal yet grotesque adult amusement. The design elegance of the circuit is enhanced by the fact that there are no moving parts, the variable resistance of the screw contacts being dependent upon how tightly they are squeezed. Man and machine, at One in the space-time continuum. Very cool.