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.
Our Sconic Sections post was highlighted in an article in the science section of today’s New York Times. The article covered several science and engineering topics in addition to geometric food (including George Hart’s Möbius bagel).
Previously: Edible Googly Eyes in the New York TImes.
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.
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.
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!
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.
Another project that captured the kids’ attention was a Keepon by BeatBots. Other demonstrations included a quadcopter and a hacked hexabot.
We got to have lunch in the bright sun in the courtyard with Avary Kent, who was demonstrating the PuzzleBox, a brain-controlled helicopter.
Sylvia got to give the PuzzleBox a try, triggering it to fly as soon as she concentrated hard enough.
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.
Apparently the poor Pleo on this bench needed some repair.
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.
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.
Thanks to Paul and Atmel for inviting us to visit!
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.
Peter wrote in about his experience with the Digi-Comp II:
I just wanted you and the entire Evil Mad Scientist team to know that the Digi-Comp II was a big success. I used it to explain digital computers to a group of second graders and fifth graders. In an age of iPads and smartphones, it’s surprisingly hard to demonstrate the beauty and magic of digital computer. The Digi-Comp II was perfect, looked great, and worked flawlessly. Thanks!
The folks at BoldPort have created PCBmodE, free open source software for designing printed circuit boards, but with an artistic perspective. Traditional EDA tools are designed from an engineering perspective, whereas PCBmodE treats the PCB as a creative palette. They aim to give you freedom to express your design with all the tools of the medium.
We wanted to create circuit boards that have curvey traces, meandering paths, and multiple soldermask layers, so we developed PCBmodE (say “PCB mode”), an open source Python software that unshackle us from the constraints imposed by traditional PCB design tools. We use the power of Inkscape — the leading open source vector graphics editor — to achieve any shape imaginable. Together with our powerful back-end tools, we can manufacturable beautifully functional boards.
They’ve posted about several of their example boards including pieceof (pictured above), a Raspberry Pi daughterboard called shimmy, and a tribute board dedicated to Bob Pease. This is a really neat approach to building circuit boards, and it looks like it has a lot of potential.
The conic sections are the four classic geometric curves that can occur at the intersection between a cone and a plane: the circle, ellipse, parabola, and hyperbola.
The scone is a classic single-serving quick bread that is often served with breakfast or tea.
And, at the intersection of the two, we present something entirely new, delightfully educational, and remarkably tasty: Sconic Sections.
In what follows, we’ll show you how to bake cone-shaped scones, to slice them into plane geometric curves, and to highlight those curves by selective application of toppings. We’ll also discuss some of the methods that didn’t work so well, as we refined our methods for making these.
Onwards, towards parabolic preserves and hyperbolic Nutella!
Continue reading Play with your food: How to Make Sconic Sections
When we recently wrote about looking at solder paste up close, we happened to mention that it has a shelf life— something that you might expect to be uncontroversial considering that there is an expiration date, printed right there on the jar.
But, our reader Trav commented
Very nice pics. What happens to solder paste when it expires? does it taste funny? Do the balls go flat?
I assume the paste rather gets runny and doesn’t hold the solder in place or it gets thick and won’t spread evenly.
I’ve heard of it expiring, but never knew how. I’ve had a tube of flux for 20 years now. When it gets too thick, I put in a couple drops of alcohol and it seems to work good as new.
We like the “balls go flat” theory! But seriously, we presume that they wouldn’t label paste with a short shelf life— typically 4-12 months, when kept refrigerated, depending on the type of paste —unless there were a reason (and hopefully, a good reason) to do so.
A blog post on the Indium Corporation web site offers a little insight. It turns out that the “activator” chemicals within the flux, which serve to clean oxides off of the surfaces that will be soldered, also interact with the microscopic solder balls, gradually scouring off their surface oxides. When the solder particles are clean enough, they can actually cold-weld together, resulting in increased effective grain size and viscosity. As Trav notes, adding a little alcohol can reduce the viscosity of flux, but we can see how increased grain size and other factors (such as having used up some of the activators) could affect performance in other ways.
But in any case, it sounds like there are a range of experiences out there, and we would like to open the question for discussion: What has your experience been with out-of-date solder paste? Has it worked just fine? And if not, what was the failure mode?
Separately, what about (flux-cored) solder wire?
Kester has this to say, in their policy about shelf life:
Flux cored solder wire has a limited shelf life determined by the alloy used in the wire. For alloys containing more than 70% lead, the shelf life is two years from date of manufacture. Other alloys have a shelf life of three years from date of manufacture.
So, our spool of lead-free solder pictured above, with date of manufacture 3/16/05 expired five years ago in 2008. Presumably one reason for a stated expiration date is that the flux becomes less active over time as it interacts with the solder metal.
But in our personal experience, this kind of solder seems to generally work just fine, even many years past its nominal shelf life.
Many others seem to have had a similar experience with solder wire.
When we wrote about assembling a vintage Heathkit, we mentioned that it came with solder. It actually came with two little packets of solder, specifically 60/40 rosin-core, cheerfully labeled “Made Expressly For Heathkit by Alpha Metals, Inc.”
Seeing as (1) the kit and solder date back nearly 40 years, (2) Alpha Metals also uses the three-year figure for shelf life, and (3) we already had a fresh, open spool of Alpha Metals 60/40 rosin-core solder in the lab, we opted to use the fresh spool and save the vintage solder packets for a rainy day. Were we wrong to do so? Certainly, some of our readers thought so:
Solder shelf life? Are you sure about that? Solder paste has a shelf life but I’ve never heard of a shelf life for a real coil of 60/40 rosin core solder. I’ve used some pretty old stuff myself, a quick Google search for solder shelf life found me a discussion where a guy is talking about using solder from the 60s with no problem on the first click!
So what has your experience been? Have you used “old” solder, and if so, how well did it work?
You may already be familiar with Super Awesome Sylvia, who has been working hard with us on the WaterColorBot toward our planned launch in July. Sylvia was just featured in the June 24 issue of People Magazine. Way to go, Sylvia!
Previously: White House Science Fair Roundup
