feedback mobile

so, after many different tries and much sweat and electrocution i have constructed this monstrosity of a mobile. somewhere in the greater philadelphia area, calder's corpse is shrugging its shoulders and claiming non-involvement. this has been a lesson in fabrication. the theory behind it is cool too, but the majority of the heartache came from trying various ideas out and having each one end in abject failure. i have learned the following:

1.) do not expect wood that you cut against the grain to be nearly as strong, or look nearly as good as a piece you cut with the grain. this is especially true for smal strips of basswood.
2.) always have a duplicate, breadboarded copy of the circuit you are trying to solder onto perfboard. unless you like confusion.

3.) it never looks the way it does in your brain. ever.

4.) touching a bare, live piezo disc across the crystal side will electrocute you. if it is buzzing softly and running straight off of a dc circuit this is fine, but if it is heavily amplified with several gain stages and uses an inverted power transformer to do so, this is exceptionally painful.

5.) it never sounds the way it does in your brain. ever.

6.) you won't leave enough room for the wires.

7.) the fewer constraints you put on something, the fewer chances you have to screw up.

8.) steel wire will break if it gets too gnarly.

9.) hot glue is hot. so is molten solder.

10.) if your piezo disc is not making sound and has just shocked you (see no. 4), NEVER put your ear up to it just to make sure it is malfunctioning.

i assure you, i'm ok. nothing was plugged into the wall. nor will it ever be, at the rate i'm going. i would much rather pay for batteries than go out smelling like a poorly cooked hamburger.

it's a mobile, consisting of 7 rectangular basswood strips centered around a single 30 gauge steel wire. at the bottom hangs an open box with the custom electronics inside. off of each of the wood strips, minus the lowest one, hang two steel wire "whiskers." the electronics consist of a home-made distortion circuit and a driver circuit for two piezo discs, one which acts as the microphone, the other as a speaker. these discs also have whiskers soldered onto them; three whiskers each. the microphone's whiskers are the longest, and hang down with the aid of washers affixed to the ends. the speaker disc is affixed to the bottom of the components box, and amplified to the point where the entire sculpture vibrates and acts as the source of sound. the microphone is affixed to the central wire that holds the structure up. as a result it is incredibly sensitive to the microscopic movements of the system. as you might imagine, feedback ensues through the system, creating patterns of tones and creaks even while the sculpture might appear to be completely still. this concept was adapted from an earlier idea to use photocells and analogue pulse oscillators to sonify the balancing system. the photocells were scrapped because i became unsure if light was the best attribute for the system to respond to. i may eventually add some kind of motor based agitator to the system if there is time before thursday.

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