The Printr Egg Boogie Board Bot

Printer Egg Boogie Board Bot

Over at Thingiverse, user gkrangan posted this wacky contraption: A machine to write with a stylus on a Boogie Board e-writer, built from PrintrBot Simple frame components, along with EggBot electronics and the pen-holder.  It’s driven through the EggBot extensions for Inkscape.

I was initially taping an index card onto the print platform for testing purposes, but when I saw this Boogie Board at a toy store, it seemed like a perfect choice to be used as the writing surface. One can draw/write anything on it, and erase with a press of a button. Of course, it can still be removed and any other suitable surface can be taped or mounted on the print platform, as necessary.

Printer Egg Boogie Board Bot @ Thingiverse

From the Mailbag: Understanding the Homopolar Motor

Wes wrote in to say:

I am an Electrical Engineer (graduated May ’72, Texas Tech U), but I never saw or even heard of a homopolar motor until last week, when I saw an electric motor made from four parts on National Geographic’s program, “None of the Above“. When I first saw it, I figured it must be a hoax. A DC motor had to have a commutator and two magnets.

Only when I was browsing around in Wikipedia did I find an article on the motor. I happened to have everything I needed, so I built one, not really expecting it to work. To my great surprise, it spun up to a few thousand RPMs in seconds. I read Wikipedia’s theory of operation, but it didn’t make sense. Today, I came across your wonderfully clear and simple explanation, and now I understand the motor perfectly.

I simply cannot thank you enough for your drawing and explanation.

Thanks for writing in— we’re glad to hear you enjoyed learning something new! The instructions for making the motor and the discussion of how it works are in our articles:

Simple Relay Shield v 2.0

relay shield

A minor bump for one of our little open source Arduino add-ons. The Simple Relay Shield is an easy to use single-relay board that does one thing, and does it well: It adds a beefy little mechanical relay to an Arduino, which you control through pin Digital 4.

relay shield

Version 2.0 adds the ability — by popular request — to control it from a pin other than D4. Solder the jumper in the normal way (in location JP), and it works on pin D4. Hook it up to any other digital pin, say to D7, and now you have a relay on that pin. The Simple Relay Shield is available as a complete soldering kit or as a bare PCB, and you can find documentation on our wiki.

A Vintage Bliley Crystal

Bliley Crystal 1
Bliley Crystal 2 Bliley Crystal 4
Bliley Crystal 7 Bliley Crystal 6

They don’t make — or package — them like they used to. This is a vintage radio crystal from the Bliley Electric Company.  Bliley is still around, making modern oscillators and even space flight hardware, but this vintage unit is a beauty.

Introduced in the 1930′s, the Bliley LD2 was a popular frequency standard for amateur radio operators. A 1935 advertisement in QST magazine claimed efficiency and extremely low drift (<8 ppm/°C), guaranteed operation, an improved holder, and a cost of only $4.80, or $82.79 in 2014 dollars.  This particular unit is calibrated at 3.9895 MHz (“3989.5 KC”), for a radio wavelength of about 75.2 m.
Bliley Crystal 9

 

Unlike most modern crystals, this type comes apart easily. Inside, two rectangular steel plates sandwich a thin slice of quartz crystal, all held pressed together with a simple spring.

If you’re interested to learn more, there’s a wealth of additional information about vintage crystals and the Bliley company available online, here.

Interactive art at Helix

Romy Randev of Looma is installing his latest piece, Penumbra at the Helix museum in Los Altos.

Penumbra is an interactive installation that responds to movement in its environment. Without any human interaction, Penumbra is disguised as a decorative glass wall. However, each colored glass tile illuminates individually as sensors that respond to movements control LEDs behind the glass.

Penumbra makes use of our Octolively modules, and we’ll be at Helix with Romy on Saturday March 29th, starting at 2:00 PM to talk about the art and tech behind Penumbra. Event information is available from Helix.

Three Fives in IEEE Spectrum

IMG_6354

Our Three Fives Kit was featured in this month’s IEEE Spectrum. From the article:

Just as DNA models, star maps, and periodic tables serve as reminders of fundamentals that can get obscured by day-to-day minutiae, so too the Three Fives kit is a reminder that even the most complex digital processor is still at its heart just a collection of very simple components.

You can read the full article and see pictures of it in use in a sample circuit over at IEEE Spectrum.

Basics: AVR Target Boards and Arduino Compatibility

Diavolino
Gary writes:

I have fallen in love with your Diavolinos – thank you!
My question: does the “Simple target board” allow for the 6-pin FTDI Friend hookup to upload sketches? This is quick and easy with the Diavolino. I’m new to reading circuits and stuff, and I cannot tell looking at the target board. It says to use in-system programmer, but I prefer to not buy another interface. Thanks!

Excellent question! It is certainly possible, but not as quick and easy.  Both the Diavolino and our ATmegaXX8 target boards boards use the same chip, usually the ATmega328P.  But, one might say that our ATmegaXX8 board is a simple AVR target board optimized for use with an AVR ISP programmer (like the USBtinyISP), whereas the Diavolino is a simple target board optimized for use with the FTDI interface.

XX8 Target Board

Versus a “bare” target board (with just the chip and power), there are four things that you would normally add, in order to use the FTDI interface to upload a sketch from within the Arduino environment:

Continue reading

Cool Wearable Electronics

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Mascot costumes are often hot and sweaty, and mascots are expected to enthusiastically energize their teams. At FIRST robotics competitions, there are also traditions of dance parties during delays caused by technical difficulties, leading to even more activity in a warm, heavy costume than would normally be expected.

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Cardinalbotics, an FRC team from San Francisco, made a mascot costume using an application of wearable electronics I had not considered before: cooling fans. The cardinal head was made of fabric sewn over shaped foam, with fans on the sides to keep everything cool inside.

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The fans were wired up to an on/off switch and adjustment pot which were hidden in a velcro compartment in the back of the head.