Dr. Nim

Our friend Brian (the designer of the EBB driver board which is used in the Eggbot) recently posted this picture on twitter, with the following caption:

Kids found 1966 ‘computer’ ‘game’ in the closet and LOVE it. Dr. Nim always wins. Our future may be OK.

Dr. NIM was designed by the same engineer, John Godfrey, who designed the Digi-Comp II, and it was manufactured in the mid-1960’s by the same company, E.S.R. Inc. It is even described in the same patent as the Digi-Comp II and works in the same manner, using mechanical flip-flops triggered by marbles. Only, to play the ancient game of Nim instead of doing binary calculations. We were very curious about how Brian came by one, and asked for more information. He wrote what follows:

We were on a week long vacation in Michigan. We rented a large house on the shore of Lake Michigan near Traverse City. The house looked like an extreme example of 1960’s decorating—nothing has been updated since. (Large tables with built-in ash trays, shag carpet, an old radio that had a “magic eye” that lit up when your FM radio station was ‘in hi-fi stereo’, etc.) And, in the closet with the games, was one called Dr. Nim. Us adults never gave it a second glance until one of the older kids noticed that it said “computer” on it, and pulled it out to see if she could get on Facebook with it. My ears perked up, and when I saw the front cover, I couldn’t stop playing with it. Which is not surprising considering my background as an embedded systems engineer. But what I couldn’t believe is that the kids loved it too! We were on vacation with 2 other families, each of which had 3 kids (like ours) of various ages. Very quickly, the 10 year old figured out how to beat Dr. Nim. Of course that made all the other kids want to try. Even the 4 year old learned to play. And then some of the other adults (even non-engineers) tried it for themselves, asking how it could possibly know how many marbles to take each turn so that it would (almost) always win. “How can pieces of plastic be a computer?” they asked. So we had a nice chat about where the term ‘computer’ comes from.

The thing that got me most excited was not that (modern) kids picked it up and were fascinated by it, nor that other adults were intrigued, but the thought that, in 1968 when it was available for sale to the general public, enough normal Americans bought it that it ended up in people’s game closets along with decks of cards and Monopoly. I suppose the thought of owning a ‘computer’ when such things were all the rage, was so new that spending a few dollars on a plastic mechanical game computer was something a lot of people did just out of curiosity.

And the instruction manual! I should have scanned it in. It has a mini-course in binary logic and boolean equations, ending with a discussion on how the game works, and how you can set it up in several different ways to play different games. And then it went on with “does this mean Dr. Nim can think?” and the open ended questions of machine thinking.

Too bad somebody doesn’t make something like that today . . . .  <grin>

After Brian wrote back to us, we found the manual for Dr. Nim through the Friends of Digi-Comp group. (Dr. Nim games frequently come up on eBay as well, if you’re interested in playing with one.)

The manual is truly incredible, with in-depth discussions about not just the mechanism of the game, but commentary on the effect of computing on culture in the long run. We’ll leave you with a thought from the manual, c. 1965:

The strides that man has made in the last 15 years in developing machines that extend and supplement his thinking are truly astounding. Who can say what enormous strides will take place in the next 15 to 30 years?

Followup: Solder Expiration

Solder 3
When we recently asked the question, “Does solder expire?” you gave us some excellent answers. Many commenters had a story similar to haineux’s (sometimes replacing 1960’s with 70’s, 80’s or 90’s):

Just recently used up a spool of my father’s early-1960?s-era solder from Lafayette Radio Electronics, and now I’m working on a later-60?s spool labeled “Archer” (a Radio Shack house brand).

There might be some reason new solder is better for something, but I’ve not had any troubles doing standard PCB and parts soldering.

Steve had a great story about learning to solder with a roll of 1/8? flux core solder:

The last time it had been used (~20 years previous) it hadn’t been sealed — the flux core was open to the air. About a foot of it had dried up and evaporated. I didn’t know what I was doing so I didn’t notice at the time, but kept cursing because the solder wouldn’t stick to anything. Eventually I used the roll down to where the good solder lived and it started to flow properly, but it was a frustrating way to learn to solder. The outside of the solder was pretty corroded, a fuzzy matte gray, but it heated and flowed like anything else with fresher rosin.

To this day, whenever I solder with larger gauge solder I make sure the tip of the solder tube is closed before putting it away. I figure it will be good for another 20+ years that way.

Brad had a slightly different perspective:

Old solder might be perfectly “usable,” but try using a 10 year old spool and a brand new spool one after the other on a small-pitch SMD part, and tell me that there isn’t a big difference!

After noticing this for the first time, I never buy more solder than I can use in a couple years.

Paul reflected on different applications having different requirements:

At work we are required to throw out “expired” solder and solder paste. It is a liability problem, the FAA hates to find expired chemicals and uncalibrated equipment on their inspections.

At home I have used twenty year old rolls. My stuff at home is just for my use and no ones life is at risk.

So the general consensus seems to be that rosin core solder will work nearly indefinitely so long as the rosin isn’t affected by storage conditions. Even then, as long as the bad section is removed, the rest will work fine. A few connoisseurs prefer newer solder (especially for small parts), and industrial applications may require strict adherence to expiration dates, but many of the rest of us will continue to use our (long) expired solder until it’s gone.

A round up of our “Basics” articles

  SolarCircuits - 06
Soft Circuit Merit Badge01  g22023

Over the course of the past few years, we’ve been writing occasional “Basics” articles, about introductory topics in electronics and microcontrollers.  In the spirit of making things easy to find, we’ve now tagged them so that you can find them with this link, and we’re collecting them together in this index that will be updated from time to time.

Our “Basics” articles about electronics in general:

Additional “Basics” articles about working with AVR microcontrollers:

DIY Hatbox Stamps

Matthew Borgatti recently put up an excellent post about the process of creating a hat box stamp for Pork Pie Hatters:

A professional looking tool made from a few simple digital fabrication techniques and some easy hand finishing. I really love when a process can be this straightforward and precise and take the hand crafting out of the equation. Laser cutting allows me to put the time and labor and love in the conception step and not on the execution.

He walks through the details of the aesthetics, design, fabrication and finishing.

Time Lapse Fog over San Francisco

Adrift is a beautiful short film by Simon Christen chronicling the fog of the San Francisco bay.

I spent many mornings hiking in the dark to only find that the fog was too high, too low, or already gone by the time I got there. Luckily, once in a while the conditions would be perfect and I was able to capture something really special. Adrift is a collection of my favorite shots from these excursions into the ridges of the Marin Headlands.

Via @drwave.

Bullet Time Fireworks with a GoPro and a Ceiling Fan

fireworksfireworks

Just in time for the Fourth of July, Jeremiah Warren created an incredible relatively low-budget “bullet time” rig— with a 240 fps GoPro camera mounted to a ceiling fan —to photograph fireworks. He posted a full writeup showing how to build it on his web site.

fireworks

fireworks

The clever hack about using the GoPro on the ceiling fan is thanks to Mark Rober, who showed how to do it back in May, mostly with smaller-scale subjects.  But Jeremiah has taken the idea and run with it, adapting it for larger-scale photography.

And as you can see, the results are simply fantastic.You can find more videos and the full how-to on Jeremiah’s site.

Field Trips: Atmel Headquarters

Sylvia

Super Awesome Sylvia and I were invited to attend Bring Your Kids to Work Day at Atmel recently. (Atmel, of course, is the company that makes the microcontrollers found inside Arduino products and in many of our own projects and kits.) We were there to help provide tangible, interesting, and playful examples of how Atmel chips can be used. And of course, we weren’t going to miss an opportunity to visit Atmel headquarters!

Photo courtesy of Atmel

The biggest hit with the kids were the Octolively interactive LED modules (sporting the Atmel ATmega164P). When the kids waved their hands over them, the LEDs would light up and ripple. Some of the kids would start out by poking and grabbing at the LEDs until they lit up, but as soon as I told them it would work “even without touching it” their eyes would get big, and they’d wave their hands over the top, enthralled.

Some of the other things we brought were our handheld game, the Meggy Jr RGB (with the ATmega328P); a Bulbdial Clock (Atmega328P again), which points rings of LEDs at different heights down at a central point to create shadow hands of different lengths; our giant Alpha Clock Five (ATMega644A); and the Larson Scanner (ATtiny2313A), which lights up nine red LEDs to make a scanning robot eye.

Photo courtesy of Atmel

Another project that captured the kids’ attention was a Keepon by BeatBots. Other demonstrations included a quadcopter and a hacked hexabot.

Photo courtesy of Atmel

We got to have lunch in the bright sun in the courtyard with Avary Kent, who was demonstrating the PuzzleBox, a brain-controlled helicopter.

Photo courtesy of Atmel

Sylvia got to give the PuzzleBox a try, triggering it to fly as soon as she concentrated hard enough.

Workbench

After lunch, we got to tour of a couple of labs. This workbench was well stocked with a Metcal soldering iron (our favorite) and lots of tools and supplies.

Workbench

Apparently the poor Pleo on this bench needed some repair.

Chip testing machine

This machine is for inspecting and testing chips after they have been removed from their housing.

We got to go into the RF anechoic chamber, and watch as our cell phones stopped receiving any signals.

Horsing around

We also had some time to hang out and horse around with friends new and old. Our friend Paul Rako seemed to be having as much fun as the kids.

Photo courtesy of Atmel

Thanks to Paul and Atmel for inviting us to visit!

How Printed Circuit Boards are Designed (1960 Edition)

We found this gem in A Manual of Engineering Drawing for Students and Draftsmen, 9th Ed., by French & Vierck,1960, p. 487.

Printed Circuits allow miniaturization and the elimination of circuit errors—advantages that cannot be obtained by other methods. Once a pattern or suitable design is established, preparation of a black and white drawing can start. Scales for reduction, for example, 4 to 1, 3 to 1, or 2 to 1, are used. To insure sufficient bonding area of the metal laminate during soldering operations, lines should not be less than 1/32 inch in width when reduced. Line separation should never be closer than 1/32 inch on the final circuit. Figure 19.24 illustrates the drawing of printed circuits.