Tag Archives: kinetic art

LED Chaser Tube

LED Chaser TubeI saw this really cool thing in a video about early computers that used vacuum tubes to make calculations. One type of tube had a ring of lights inside the end of it that chased each other in a sequential circle giving the impression of rotation.

I’ve always been charmed by the look of glass vacuum tubes from an early age when much of the electronics in things like radios and televisions used them. If you took the back cover off while the device was on you’d see a little forest of small glass bulbs, glowing white/amber. These were accompanied by resisters, capacitors and coils, all arranged on a brown board with lots of wires going all over. There was a smell of something hot and sort of melting. The warmth from the tubes was seeping out right at you.

Back in the 1980’s I found some large vacuum tubes (used in radio transmitters) at a flea market in San Jose California that I made into decorative lamps, by mounting the tubes above the big 6 amp transformers needed to light up the plate inside them and make them glow. They used a huge amount of power, and got very hot, but they sure looked beautiful. I experimented with a way to try and make them look beautiful like that, but not draw so much power. Using a small torch I melted a tiny spot on the side of the glass tube. The vacuum inside the tube caused the glass to melt inwards until it eventually burst inwards with a hole just big enough to wiggle a tiny “grain-of-wheat” light bulb into.  These are the little lights you often find in model railroads that only need 6 volts and very little current. If you held the tube so the wires were behind it, it looked just like a normally powered-up tube, but didn’t get hot at all. An electronics engineer friend in the Silicon Valley saw one of these on a sculpture I was making and commented on how cool the vacuum tube looked. He started looking all a round for the big 6 amp transformer that should have been there to give the tube its power. “Now wait a minute…There’s no…(still nosing all around) wait, you can’t just…” “All right (resignedly) how did you get that tube to light up?” I clued him into my little secret. “Looks convincing, doesn’t it?” “Yes, it does!” he said laughing.

The tubes I saw with the chaser lights in the video about early computers must have had small lights in them too, possibly neon. I decide to make a similar object by using a decade counter chip run by another chip that provides a clock signal. In place of lights, I assembled a rig of bright red LEDs. I had to cut the tube away from its base and cut out the original electronics to fit the LED assembly in their place. I’m really happy with the result! You can see a video clip of this thing in action at my KARF website: https://karflab.wixsite.com/mysite/news

 

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Document Scroller and Optical Reader

Document Scroller

document scroller 72dpiKinetic forms have long been a staple of my sculpture. The stations in the KARF installation each will need a number of kinetic devices that indicate information in action like a computer screen munching data. I have built a box for Station 2 that has a motor driven loop of canvas with small documents stapled to it. When the motor runs it slowly drives the loop and draws the documents past an opening that is framed with an antique bronze frame. I made the documents from scraps of junk mail, old tax forms, defunct carbon copy receipts, all that I drew on with my crabby symbols, scratches of figures, smudged glyphs. Matching up distressed materials and quirky technology like this brings up this mood in me that I think other artists and inventors may have experienced. It’s a feeling of jubilation at overcoming crude materials to succeed at a sculpture that previously had only seeped around in my mind.  Here it is mounted to Station 2. Wiring still to be connected that will run the motor and a small light that illuminates the document inside the opening.

Optical Reader

The optical reader is a component of the document scroller that is added to the front.  I wanted a slightly random device that would mechanically move a small lens back and forth, at varying intervals in front of the document scroller window.

OLYMPUS DIGITAL CAMERAI recently got to working with servo motors-the kind that hobbyists use to operate parts of remote controlled toys- and developed a circuit that would make the servomotor move the way I wanted. I like most of the motorized devices I make for my sculptures to have a bit of their own personality. Certain kinds of motors, like servomotors or gear motors and the custom driver circuitry I develop for them gives them the personality I’m after.  It can be a consuming challenge involving lots of tests and adjustments to make the motor move in a special way.

The main challenges are the mechanisms that the motors move and the timing of the motor’s operation. I start with some mechanical elements that I hope will give me the movement I want such as a linear slide, in the case of the optical reader. I long ago found some really nicely OLYMPUS DIGITAL CAMERAengineered slide parts in old computer disk drives.I scavenged one from a disk drive I’d stuffed away in a box, welded the chrome shaft to a small mounting plate, screwed that to a chunk of wood and mounted the servomotor to the opposite side. Then I joined a bit of stiff wire between the motor’s rotation linkage and the carriage that slides along the chrome shaft. Three circuit boards provide timings to the servomotor telling it to go left or right at various times and durations. Testing with various values of electronic resistors, knowing a basic range of what would give me the movements I wanted quickly gave me the results I wanted.

Optical Reader in left position

Optical Reader in left position

Optical Reader in right position

Optical Reader in right position

 

The carriage holds the antique lens and a little sculpture I named the ‘optical reader node’. Here’s a sketch I made as I was playing with the parts I thought might work on it.

sketch of opto reader node

sketch of opto reader node

You can see how the actual optical reader node evolved from the sketch.

Optical Reader Node

Optical Reader Node

 

 

 

 

 

 

More about the KARF installations:https://karflab.wixsite.com/mysite