Category Archives: Physical Computing

DIY 3D printer

I was researching parts to build a stepper controlled coil winder and came across an interesting listing on eBay:

StepStick Stepper motor driver A4988 A4983 3D Printer driver module Reprap Prus

StepStick Stepper motor driver A4988 A4983 3D Printer driver module Reprap Prus
A little more research and I came across the site for a DIY 3D printer.  Don’t know if it will work or how well it will work.  From the photograph, it certainly looks good.  But then again I have also seen photos of aliens on the internet and videos of politicians promising things would be different.


The video looks great. Especially the part about being able to print electrically conductive material. I’m a sucker: The dispersion of this technology represents change I can believe in.  Especially if it can be scaled up and use materials which have or have not yet been invented.

Printed Circuit Boards: 1903 – 2013

A quick on-line search and I found out that the ubiquitous circuit board had its start in 1903 thanks to German inventor, Albert Hanson.

It looks as though a hundred and ten years later the technology might be catching up with our desktops:
Screen Shot 2013-11-17 at 9.55.28 AM

The process uses an inkjet printer whose hacked cartridges lay out an ink of conductive silver (for the time being).  As a side note, a recent field trip to NYU’s Advanced Media Services revealed that one of the rapid prototyping machines uses HP inkjet cartridges to print rock-hard objects using what may have been gypsum as the binder.

In the same way that the hand-drafting of printable wiring diagrams was replaced by CAD, this printable technology would be welcomed by anyone who has ever had to figure out how to best dispose of the toxic sludge which always results from the chemical milling of copper-clad circuit boards.

Like using whale oil for lighting, some technologies should be retired.

There is a kickstarter for a promising project… heck, I want one too.Screen Shot 2013-11-17 at 1.26.36 PM

Peter Terezakis
ITP Master’s Candidate
Tisch School of the Arts

The Uncertain Destiny of Nature, Humanity, and Technology.

My final project for PCom will revisit a theme from a previous work. The project will consist of an aquatic environment with lights controlled via an Arduino through users on the web. The environment is a fish tank: It’s a fish reality show.This is a team project which will be built with artist Vitor Freire (Vitor’s ITP blog).

Glass Beads

Hollow and solid glass microspheres and beads have been used in consumer and industrial products for decades.

My first purchases of glass spheres  was from Golden West Manufacturing during the mid-1980s.  In those days something called “Thomas Register” was the Google go-to for manufacturing research.  It was also where I looked for an inert material to use as an extender-filler in silicon mold making.  I later used glass beads when manufacturing luminous jewelry.   Goldenwest still sells glass beads:
Screen Shot 2013-10-31 at 9.51.18 AM HG3000 FILLER  HEAVY SOLID GLASS MICROSPHERES  PURPOSE: For use as a very high quality filler for R1 FAST CAST®  to strengthen the finished casting, increase the density, minimize shrinkage (less than 1/32" in 12", 50/50 volume blend), create a glass smooth cell structure and make unlimited thickness in one pour without cracking with FAST CAST® 709. The HG3000 FILLER is manufactured under rigid QC methods and has such a low moisture content that it will not cause resin problems as do other similar fillers. Again, this is where good quality control saves through less rejects. We have tested many brands and types of fillers and we only accept the best. USES: Blended 50/50 by volume with our #709 resin to make our Machineable Plastic R1/HG3000 composite tools, patterns, reference fixtures, vacuum forming and plug assist tools and industrial castings. 1 Quart Container, 1 Gallon Container, 5 Gallon Pail, Bulk ContainerDuring a 1994 studio visit with Dennis Oppenheim I suggested that he use glass beads as an additive to polyester castings for his Rabbit Factory series.

Clicking on the Goldenwest images above or those below will open links to purchasing glass beads.

Solid Glass Beads

“Properties of polymers are often modified by quasi-spherical mineral fillers such as calcium carbonate or by highly anisotropic glass fibres for an efficient reinforcement or by foaming to reduce their density. Solid or hollow glass beads partly combine the advantages and also the drawbacks of those techniques allowing to modify mechanical, optical and thermal properties, density and cost of nearly all the polymers. Their adhesion to the polymer matrix can be optimized by sizing with coupling agents. Moreover, glass beads have unique optical properties and can be modified by surface treatments to obtain electrical conductivity. Consequently their application field covers a broad domain comprising polymer enhancement or lightening with hollow glass beads having a low density, syntactic foams used for buoyancy, reflective products for signs and marking, electrical conductivity for metal coated glass beads used in electronics. Solid glass beads have a density of 2.5 g/cc, a high crush strength and a Moh hardness of approximately 6.” SpecialChem, 2006


Expensive – because they are worth the money.

The entire family of Pomona banana jacks and plugs are engineered works of beauty – and function.  They are reliable, robust, and were designed by engineers for engineers.  If you know what you are looking for, you can find them for less money than what they are currently selling for on eBay.  Click here for the Pomona Electronics data sheet.

Screen Shot 2013-10-05 at 10.21.00 AM Screen Shot 2013-10-05 at 10.21.09 AM Screen Shot 2013-10-05 at 10.21.27 AM Screen Shot 2013-10-05 at 10.21.54 AM

Universal Unlimited Command & Control Console

Universal Unlimited Command & Control Interface, part 1.

Dreams are meant to be channeled here.  Creative thought engendered through haptic, auditory, and visual feedback of a polyutilitarian assemblage of electronic and mechanical components.

Here is version 1 after laser cutting and bonding of acrylic:


A friend remarked that it was difficult to see.  I tried to explain the transparency of function aesthetic and was met with a blank look.  The image below should make the interface easier to see.


If you still have difficulty, here it is on its own.  Unfortunately, I have run out of nuts to fasten the binding posts and banana plugs in place.  This is a giant bummer.  I have containers of them at my studio in San Diego.  Looks like time to break out the hot glue.

I’ll start soldering tomorrow after I install the rest of the contacts.





ITP challenge?


So this has been done.     Greg Gage’s Ted Talk is interesting.

I wonder if there is anyone at ITP interested who will consider upping the ante from insect to experimenting with a small mammal (cat or a dog)?   I see this as not only a possible road of exploration post-ITP, but as an inevitable milestone on the way toward a future where society will be able to use those deemed as marginally functional human beings as remotely operated droids.

Like evolution, corruption is a gradual process.   It is ironic that the “youthful blasphemy” of H.G. Wells’s nineteenth-century Dr. Moreau, created the possibility for the twentieth century’s otherwise unimaginable Dr. Mengele.    In the second decade of the twenty-first century, what has now become commonplace and taken for granted was once considered horrific, monstrous, and/or obscene.   I’m sure you can think of  a few examples without my citations.

What was once in the realm of science-fiction fantasy or horror is an inevitability.

Remember what Jean-Luc said… [sc_embed_player fileurl=”″]

Bits, bytes, parts, pieces, and (sigh) not a spark in sight.

This post is a compilation of a series of Physical Computing exercises. I confess to having allowed them to build up (mea culpa, Professor).

The first image is from an exercise where we read varying resistance into one pin of the Arduino.


In the image above you can see that I have a Light Emitting Diode (LED) on my board which isn’t the wiring diagram for the project.  I often use LEDs to make certain that what I am working on is powered.

The image of the board below shows the convention of wiring as I read: left to right. To the left, red is high. To the right green is ground. Rotating the test fixture a quarter turn puts the Arduino at the top, ground at the bottom. Pretty similar to printed wiring diagrams/schematics.


Going slightly off-tangent, I believe in the power of hot glue, which is actually not a glue at all.  Hot glue is a relatively low-melt plastic which is used as an adhesive. I have to make a separate post about hot glue and its use/misuse in the studio.

Great tool if you use it right. It will take your skin off if you do not. As with every tool, you must pay attention to what you are doing.

In this image below you can see that I put a generous dollop on the back of an 8 ohm speaker to hold a power connector in place. Yes, this is waste of a connector. But since I am powering the Arduinio via the USB cable, I had a perfectly good connector available to use on the board. I also didn’t have any self-adhesive velcro which I use from time to time.

BTW – once in a while (more often than not, really) things don’t go quite as you think they should. I’ll leave you to cite your own examples. But this uncertainty is part of building anything.


After running the PWM code for the circuit under test, I kept getting inconsistent results. No longer able to afford pulling one single hair out of my head out of frustration, I was able to call on Professor Feddersen. Jeff came over, took a look around the board, asked a couple of questions, and somehow we looked at the connections to the speaker. Turned out that one of the connections had ALMOST broken loose and was held in place only by a tiny bit of PVC insulation. This was the cause for the intermittent and eventual total failure of the speaker’s operation.

After thanking my professor, I resoldered both connections AND – as you might have guessed – hit them with another generous helping of hot glue. Here the hot glue not only acts as an electrical insulator. It also acts what is called a “strain relief.” The stranded speaker wires are allowed to flex within their length as they are moved about – not at the solder joint which could (did) easily break free.

The image below shows a terrible use of a male-male header strip, hacked into submission to become an electrical connector. The cool thing about header strips is that the pins (these are square for wire wrapping) are plated to not only prevent oxidation, but also to be easy to solder (yay!). The pins are also on .10″ centers – just like the holes on the experimenter board.


Yes, I feel guilty about the profligate waste of space and material. Usually I am much more frugal with materials. But – there was a bin of them and they looked so… available!

This means the header can be pressed into the experimenter board with relative ease. Bad thing about the headers is that they are not designed to be used the way that I am using them. This means that they will easily snap (they are actually designed to do that!). You probably know what that means? Yes. More hot glue to the rescue. Again the molten plastic will keep the wires from flexing at the solder joints and, as a bonus, the plastic will help to prevent the strip from breaking apart.

Hot glued header

You can see from the photo that I used several pins for each of the four connections which I needed. I could have done with a lot less wasted space. But there weren’t a lot connections in the project and I wanted to have more mass and material to work with than less – especially given how delicate the part was.

Building these homework projects was a little frustrating. I didn’t have all the correct resistor values in my NY studio.  Unless you are fortunate to have walking access to unlimited proto-typing resources (you should have seen what they had available at Bell Laboratories!!) challenges will present themselves when converting an idea into a physical object  whether you are in your studio or on location far from home.

When you start building you need to be able to use everything around you to get the job done (before the opening!)  and not go running to Radio Shack (or crying to  your mom).

Factoid #3,456: Improvisation is one of the keys to successful hardware hacking.

Resistors are about the easiest thing to work with. They are inexpensive when you buy them in bags/boxes of 100 – 1000 pieces.  I use a lot of 1/4 1% metal film resistors.  There are other flavors (carbon, wire-wound, non-inductive, etc) but for most of my applications, this is what works for me.


At the bottom of the image above is an example of how resistors in series will add their value – put twelve 220 ohm resistors together and you will measure 2640 ohms (2.64 k).

In parallel (like in the image below) their value goes down by 1/2 and their current dissipating ability is doubled. In other words, two 1/4 watt one thousand (1K) ohm resistors in parallel will have a new value of 500 ohms and be able to dissipate 1/2 watt of energy before bursting into flames! (Just kidding, they rarely burst into flames. But they can get hot enough to burn you if you do something wrong.)


Other experiments included generating tone(s) using the PWM command – which is a powerful tool. I might use this command to control a stud welder I recently purchased from Craigslist.    For class we used this command to sound some tones.  With Classmates Justin and Corey, we worked on making a light-sensitive musical instrument.   The hardware was simple.  The code was also simple for reading one input.  We had trouble getting three to work at the same time.






Hmmmmm….. now don’t these amazing things look interesting???


(to be continued…)

“Academics get paid for being clever, not for being right.” – Don Norman 2011

We had some reading to do for class. It wasn’t only that I took exception to dated text. I  get persnickety when it comes to presenting ideas regarding art, design, history, politics, and technology to artists.   Then again some say I am persnickety in general.  Anyway, the first reading was Don Norman...

Don Norman -- Human Centered Design Professor Emeritus Departments of Cognitive Science and Psychology, UCSD  "People Propose, Science Studies, Technology Conforms" My person-centered motto for the 21st century.  (Also the epilog of "Things that make us smart." Addison-Wesley, 1993.)

I was bored to tears by the insipid, clever, whining of Don Norman about design.  Reading Norman was reminiscent of someone attempting to divert accountability for keyboard entry errors (due to a lack of understanding) by referring to anomalous events as computer “glitches.”   His tone is not dissimilar from the individuals  who detonated ALL of the fireworks at once for the 2012 Fourth of July display in San Diego (call it a case of premature detonation) and blamed it on a “glitch.”

“Glitches” went out as an excuse for failure by all except the most non-technical illiterati after the release of MS-DOS 2.0 right after the, “dog ate my homework.”  Though a case might be made for persistent glitches in Windows operating systems right up to XP service pack 2.

As usual, I Googled the writer.   On his UCSD teaching site Professor Norman had this to say:  “Today’s technology, especially that of the Personal Computer, is too complex.  But the potential is enormous. ”   You would have thought that an MIT EE & Computer Science graduate would have been a bit more forward thinking.  Professor Norman was certainly correct about the potential of the PC, even if he failed to grasp what was so unique about the protean nature of  microprocessors.

Creating the mantle of cognitive scientist, he was able to focus on exploiting the insecurities of others of his generation – and his seniors.  He made a career out of being a whiner: inventing problems was a realized necessity for his job:

“Academics get paid for being clever, not for being right.”   –  Don Norman, 2011

Professor Norman’s quote is a good lead in to what I thought while reading Bret Victor’s, “Brief Rant on the Future.”    Yes, I agree with a possible interface of the hand with accompanying gestures.

Let us bourree beyond our cro-Magnon ancestry, beyond Bret Victor and his hammer.  What of speech as an interface?  I talk to the machine, it talks back to me (ideally telling me that it did what I asked).  If Apple quit being so Microsoft these days, maybe they would fix Siri and we would be one step closer to a better interface for everyday uses.

Or how about multiple manners of human-machine interface?  Why must there be an exclusive interface?  What ever happened to choice?   In my studio I have eleven hammers, each one for a different job.  I cannot use a sledge hammer to drive a tack (accurately, anyway), any more than I can use a ball peen hammer to drive a wedge to split a log: match the tool to the task.

While the future is never what anyone says its going to be, the seeds for tomorrow are  around us now.  Engineers and designers will continue to experiment and innovate.  Today’s machines will evolve in order to successfully compete in the global marketplace.  Ultimately it will be the customer who will determine the evolutionary paths of products.

About a year ago I was complaining to an Apple technician about not having control over the system font size on the iPhone.  He patronizingly told me that Apple was planning on making smaller devices, not larger, and that I should look to another vendor for a phone.   Now Apple is planning on rolling out four and six inch phones in response to the pounding they are taking from Samsung and others.

Bummer that Apple has become so much like Microsoft.  But this is the fast moving near-present; not the future.