learning the ropes

Idea:“Grass Grows from the Middle” is a musical field which imitates the feeling of moving through stalks of wheat. As the user moves through the field, different music samples are played.

Description:
The first iteration of “Grass Grows…” is a 3′ x 3′ prototype containing 10 5′ high stalks. Each stalk is programmed to play a different starting point in the first movement of Stravinsky’s “Rite of Spring.”

Team:
Michael Chladil
Shlomit Lehavi

Exhibitions:
ITP Audio Art Show (April 30, 2007)

Process

Description
“Musical Spinning Tops” is a kinetic sculptural curtain which incorporates salvaged parts from hard disk drives to highlight the theme of reuse and the cycle of products from raw material to designed object and back to raw material.

Spinning toys such as tops and gyroscopes transform from one shape into another. No matter the starting shape of a top, once it rotates it forms the shape of a circle. In recycling, a similar process occurs. The designed shape of an object, after its operating lifecycle is complete, is transformed back into raw material and then back into a new designed object. The rotation of elements in the sculpture refer to this process.

Team:
- Michael Chladil
- Greg Stringer

Process

I made Spanish Omelettes for breakfast at “makeBreakfast” (or “Alice’s Restaurant” as I’ve been calling it) on April 25. Shinyoung was my guest.

Images from the latest building session.

I made a solid wooden frame to hold one of the aluminum pulleys. There’s a problem, though. The shaft exhibits a fair degree of wobble when the gyroscope is spun. During critique on Thursday, it was suggested that there should be a piece of metal in the hole so the bottom of the shaft will turn more smoothly. It would be even better to use bearings… which I’ve now tried.

I salvaged bearings from the read/write heads of two hard disk drives. Mounting the bearings was tricky, though, because they must be precisely aligned. This is even more difficult for me as my bearings aren’t the same size. You can see this in my pictures of the PVC pipe gyroscope.

I think I would like to make a gyroscope frame out of metal pipe next.

The following is a record of an electronic surgery performed on 4/18/2007 in the Physical Computing Laboratory at ITP, wherein the patient “Dust” was brought to “life” in the manner of Frankenstein.

We added more details to the state machine which defines Dust’s behavior and started writing code to implement it.

We want to be able to sense how far people are pushing the poles in our installation. I thought we could do this by measuring how much force the PVC poles are exerting on the ring they’re sitting in.

Since force sensing resistors from Interlink Electronics are expensive ($5-6/each) and also because I couldn’t see how the fragile FSRs would fit into the holes we planned to use, I wanted to find a better solution.

I discovered it was possible to create FSRs out of wire and plastic wrap. Others have used conductive foam and wire mesh. Reading about linear position sensors also gave some insights.

I took 22 gauge wire from the physcomp lab, stripped it, and bent it back and forth to mimic the “fingers” on the FSRs I purchased from Interlink. After making two wire finger pieces, I wrapped one in seven layers of plastic wrap. I place the second set of wire fingers on the outside of the package and wrapped it into the existing package. My first few tests seemed very promising. When no pressure was applied to the package, the resistance was infinite. When I squashed the package, the resistance dropped down to about 10K.

The next trick was to try to duplicate this behavior on the end of a PVC pipe. We first tried applying the plastic wrap/wire packages around the end of the PVC pipe. The results were less encouraging than my initial experiments.

The homemade sensors were unreliable: either the sensor package was too tightly squashed between the PVC and the surrounding hole (and gave no resistance) or it was too loose and no amoung of bending the pole caused a reading.

This reminds me of the story of the gingerbread man — you know, he ran as fast as he could… but still ended up in the oven.

We started out with two halves joined together, but then realized that our presentation model should incorporate some of the circuitry. We cut out a door in the back to hold the speaker, LEDS, and vibrating motor.

Polymer clay (in this case SculpeyPremo) bakes for 25 minutes at 275° (or close to it).

After baking, the surface looks more matte.