How a Pinball Wizard Can Help You Repair an Exhibit

The series continues as Michael describes more of his time at the Exploratorium.  Be sure to catch up on his other posts.

The problem for this week is a set of buzzers that the kids activate by pushing buttons as part of a storytelling exhibit. The buzzers keep going bad. After a little testing I found that the low quality transformer is providing way too high a voltage. I reduce that with a lower voltage switching power supply.  With some further poking around I conclude that there is still a lot of arcing at the contacts of the buzzers so I added a crossover Zener and a blowback diode to dissipate inductive current from the coils.  This has solved the arcing problems but there is still the matter of failure due to fatigue.  What to do…what to do…what to do…? When you need inspiration at the Exploratorium you wander around with a cup of coffee and look at other peoples projects and fish for suggestions and this time I landed a good one.

After a few phone calls to arrange a meeting, I am off to Alameda to meet with Michael Schiess, the Executive Director of the Pacific Pinball Museum, because if there is one place that will have buzzers and bells that can take a beating its going to be pinball machines. What a great place. It ranges from the very old purely mechanical type machines and slowly works its way up to the most modern machines with monitors in the back and very complex interaction with the player. Michael is a fountain of knowledge on the subject and very enthusiastic, the kind of enthusiasm that is easy to get caught up in.  Since these machines reflect the popular culture of the time in which they were made, walking through the museum is like a trip through the popular culture of the U.S. for the last 80 years. While I ultimately got a lot of good information to help me replace the low quality frames, solenoids, and clappers of the old system with high quality industrial ones, what I really got was an education on how we as Americans see ourselves  through our entertainment.

Component Choices and the Ghosts of Physicists Past

The series continues as Michael describes more of his time at the Exploratorium.  Be sure to catch up on his other posts.

Within the fabrication staff at the Exploratorium there are two basic schools of thought on electronics. On one side there is the view that the older electro-mechanical solutions, involving much more physical switches, rheostats, variacs, etc. are the way to go. On the other side are fabricators eager to make use of current developments in microelectronics, such as the Arduinos that I had been installing as part of my project to upgrade the exhibits this summer. I find that I see benefits to both. I was talking to one of the engineers about this difference and his reply was simple but very thought provoking. He said that we respect each other’s opinions here, even when they differ, and that any fabricator’s idea that can’t hold up to the questioning of another  fabricator probably isn’t a good idea. Because of that, he said, these differences of opinion  and constant debate about such things are vital to the success of the projects and as a result, the Exploratorium.  That’s not a new concept to me, but seeing it manifested in actual practice on a daily basis is a very interesting thing.

As an intern, this gave me an opportunity to see the pros and cons of multiple methods demonstrated at once. In this case, it was whether to use a variac or a micro-controller to control a motor that was ultimately operated by the visitors. Here the electro mechanical controls won out because the motor needed to lose speed quickly and the low-impedance nature of the variac was quicker to respond.  I should point out that the founder of the Exploratorium, Dr. Frank Oppenheimer, didn’t like computers because he didn’t trust them. I find that quite amusing. Dr. Oppenheimer still plays a very active role in things here. I often hear his preferences invoked as an explanation of why or why not something should be done. His cane hangs on the wall above my desk. If you believe in ghosts…

Note: Frank Oppenheimer passed away February 3, 1985

Heady Days at the Exploratorium.

Michael’s saga continues at the Exploratorium.  Click here to read his previous posts.

A group of five professionals, when confronted with a problem, will inevitably come up with five firmly held opinions on how to solve that problem.

The Exploratorium is very much about decision by committee. This works very well for them. They highly value the results of collaborative problem solving, and it’s not surprising, considering how much intellectual talent they have.  Since they control the schedule of their projects they often (but not always) are able to involve a great deal of time to the intellectual consideration of many different angles and possibilities for each project. There is, to me, a very interesting contrast  between the much more speed driven, hierarchical, and often individual decision making that takes place in much of the rest of the fabrication industry.  Each approach comes with its own pluses and minuses. Groups can, in the right environment, come up with fantastic and creative solutions and products but it can be difficult to move forward when everyone must move together. The individual/hierarchical system can make quick decisions to move fast towards completion,  but that speed means sometimes great ideas get missed.  Each of these methods certainly has its place.

I am continually amazed at the collective knowledge found at the Exploratoruim. It seems that around every corner there is another person (usually in a cramped little office) with expertise in some area of science, engineering, education, fabrication, etc. The depth, and breadth, of this knowledge base is what makes this educational  machine work (although it does sometimes humorously seem like a Rube Goldberg sort of machine). I am sure that many times in the future I will think back and wish I had these resources available again.

Working at the Exploratorium

One of our fabricators, Michael Hall, is doing an internship this summer at the Exploratorium.  If you’ve missed some of his previous posts, catch up here.

For the amount of work they do at the Exploratorium, the shop is very small.  There are literally rooms and rooms of little bits and pieces of equipment and materials. The shop is fully exposed to the visitors, except the woodworking and welding areas, which are contained for obvious reasons. This is an important aspect of the Exploratorium and comes from the philosophy of its founder, Frank Oppenheimer. He wanted the visitors to be able to see not just the results of the exhibits, but the working guts as well. To that end, most of the exhibits’ workings are exposed, or at least visible, to the viewer. This applies to the shop as well. Let the visitors see how all this is made. For many visitors more education happens watching the workings of the exhibits than watching the finished product.

One of the things that struck me at first is how many women are in the shop, and at the Exploratorium in general. Having worked in technical fabrication most of my career, I have become used to the absence of women in the shop. In this shop, it’s probably a 50/50 ratio; it’s a very interesting change.  Overall, at the Exploratorium, I am certain that women outnumber men by a considerable percentage, but that just demonstrates the Exploratorium’s emphasis in promoting greater involvement of women in scientific/technical work and education.

The artists (Exhibit Techs as they are called) are very much like Taylor folks in temperament but with greater skill emphasis in interactive prototyping and almost nothing in areas like sculpture, painting, and other traditional “art” areas. The whole focus of the exhibits here is to make a cool scientific lessons demonstrated physically in a way that will teach the point and allow experimentation.  Also, it has to survive a gazillion hyper 5th graders.  To that end, everything is made of metal, lots of heavy metal. All the Exhibit Techs regularly use the old (1940s) metal mills and lathes that the shop has. That’s how everything is built. They also don’t coat any of the metal, they just let it patina from use because they found that coatings just chipped and peeled. There isn’t a spray booth and no paint department.  Nothing spray-applied is even allowed and nothing toxic at all (we are exposed to the visitors after all). They don’t even use Masonite or MDF.

A funny thing that results from the exposure to the visitors is that 700 kids at any given time is LOUD. Most of the exhibit techs wear noise cancelling hearing protection 90% of the time because its louder than a factory floor in here.

Most of the techs are kids at heart and love to rip things apart and see how they tick and how they could use those things to make something else.  One summer here is just going to allow me to scratch the surface of the collective knowledge. One of the guys I work with regularly has a PhD in Neuroscience (specializing in color perception), three have BSs in Electrical Engineering, one has a Masters in Mechanical Engineering, etc etc etc…..

I am going to spend a great deal of my time upgrading old exhibits. Mostly replacing old and inefficient motors, controls, and lighting with newer more efficient components.  LEDs are replacing all the old standard bulbs and most of the halogen lights.  The big, clunky, hot controllers and transformers are being replaced by micro-controllers. The micro-controller of choice here is the Adruino. It is very similar to the Parallax micro-controllers we used at school, but are a bit more professionally oriented. These will probably see a lot of application at Taylor.

So much to learn, my head is swimming.  It’s going to be a great summer.