Linkdump: April 2014

The Decoregger

Decoregger 1

Hey look! It’s the fossilized remains of a possible evolutionary ancestor of the EggBot!

Decoregger 2

Okay, it’s pre-USB but technically it’s not a fossil. Like many of us, the decoregger dates from the mid-1970′s. It’s a simple function gadget that mounts an egg so that you can spin it, with arm second arm that holds tiny felt-tip pens.  Curiously, there are also some contemporary machines bearing the same name that lack the separate arm.

 

Decoregger 3 Decoregger 4
Decoregger 5 Decoregger 6

In the upper-left photo, you can see that the pen holder has a separate “paddle” that you hold, to manually move the pen in the arc across the egg surface.  Lacking the proper felt-tip pens, we found that a uni-ball micro pen was about the right diameter to fit in the holder.

One surprising thing: To model this thing, we used regular “large AA” (not extra large, and not jumbo) size eggs from the grocery store. And it was only barely possible to squeeze the egg into the holders. From the picture on the box, it looks like there’s plenty of room for even the largest egg.  Possible explanation #1: Plastic shrinks over time. Possible explanation #2: The egg pictured on the box is from the advertising land of freaky micro-children.

But in any case, the decoregger is a cute little machine, and it looks like it might be fun to play with.  The actual play is a matter of turning knob 1 and knob 2, so it feels a lot like an Etch-a-Sketch in spherical coordinates. Now if only there were some way to strap a couple of motors to it and perform a CNC conversion….

Decoregger 8

Speaking of which, it really is a lot smaller than the EggBot.  Heck, you could probably fit the whole thing inside the EggBot.

Decoregger 7

Wait — am I doing this right?

Special thanks to Michelle Hlubinka for finding this artifact and sending it to us!

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.

Cameo on CNN Explains 3D Printing

Our friend AnnMarie, who is an engineering professor, wrote to say,

I keep showing the short CNN explains 3D printing video in talks I have to give to students, and always love that you and Windell are walking through the MakerBot store in it!

We were highly amused as we had never seen the clip, which was published in 2013. The footage must have been shot just after the 2012 NY Maker Faire. Having been featured in Wired Magazine for our own 3D printer, it is perhaps appropriate that when the video cuts to us, the narrator says,

The people at the forefront of this movement, they say they want this to be as common in peoples homes as the toaster oven.

(We show up for about one second at 1:35.)

The Egg-Bot Electro-Kistka

Hardware 1
Pysanky eggs

We’re pleased to announce the availability of the Egg-Bot Electro-Kistka: An electric hot wax pen designed to be used with the EggBot. A kistka is the wax tool used in the traditional wax-resist and dye (batik) method to produce colorful eggs in the same fashion as Ukranian pysanky.

We would like to acknowledge that this is not by any means the first time that anyone has strapped a kistka to an EggBot— We wrote about Ann’s DIY version a few months ago, and we’ve seen other versions (both manually heated and electric) in YouTube videos dating back several years.

Hardware
 Hardware 2 Hardware 4

The Electro-Kistka consists of two main parts, connected by a cable: A heater assembly that gets mounted to the EggBot’s pen arm (in place of the usual pen holder), and a power control board that sits behind the EggBot.

The power control board is relatively simple: it accepts input from a plug-in power supply, and has an adjustment pot so that you can set the power level of the kistka.

The heater assembly has two parallel surfaces that you can see in the pictures.  The upper is a yellow circuit board with control electronics, and the lower red part is a machined aluminum heater block that holds the actual kistka tip.

Hardware 3 Hardware 6

The kistka tip (right) has a small wax reservoir at the top and a smaller-yet point on the bottom that feeds molten wax onto the egg surface through gravity and capillary action.

Designing a good kistka tip is an art unto itself, and we are using field-proven kistka tips, wax, and other accessories from Folk Impressions, manufacturers of the excellent “white handle” electric kistka.  The tips are interchangeable and a number of sizes are available. For all of the examples shown here, we’re using only the #2 (medium) tip that comes with the kit.

Process: two-tone

The basic wax resist process is as follows: Apply wax to the parts of the egg that should remain the present color, and then dye the entire egg a different color.

Twain 1 Twain 2
Twain 4 Twain 5

For a simple two-tone image — white on black — we started with Mark Twain, one of our example images from the StippleGen project.  From a user standpoint, drawing wax onto the egg works exactly the same way as using a felt tip marker in the EggBot — it’s just a different tool that does the drawing.  The wax itself is black-colored beeswax, which is nice because you can see it against the egg.

After the EggBot finishes, we dip the egg in dye for a couple of minutes, and leave it to dry on a grid of little nails.

Twain 7

Once the egg is dry, we remove the wax with a heat gun on the low setting (a glorified hair dryer…) and a tissue. With the black wax gone, the contrast is stunning. (If you are interested, here is how it looks before the wax is removed.)
Eggbot Logo 1 Eggbot Logo 2

Another example of a two-tone egg.  Alternately, you could dye the egg before the wax resist first goes on (say, yellow), and then dye it blue afterwards. The end result would be yellow lettering on a blue background.
Process: Multicolor

overkill 1 overkill 2
overkill 3 overkill 4

Making multicolor eggs uses the same process, but with added complexity.  For this example, we applied wax resist on a bare (white) background, and then dyed the egg yellow and allowed it to dry (upper right).  We then applied a second layer of wax, dyed the egg red and allowed it to dry.  Finally, we applied a third layer of wax (lower left), dyed the egg blue, and allowed it to dry.  The results after removing the wax (lower right) show the white, yellow, red, and blue areas — not bad!

A caveat: It is harder than it looks.  While two-tone eggs are straightforward, we have found it to be challenging to precisely reposition an egg after removing it for dying. Thus, it takes considerable patience and experience to produce multicolor eggs with good registration between subsequent color layers.  We’d be interested in exploring better ways to do this.

traditional 2
Still, maybe it’s worth the effort.

MoreEggs 4

The Egg-Bot Electro-Kistka begins shipping this week.

Robot Block Party

Silicon Valley Robot Block Party Banner

We’ll be at the Silicon Valley Robot Block Party on Wednesday, April 9 at WilmerHale in Palo Alto.

See the most advanced robotics research in Silicon Valley, the hottest robot startups, the coolest robot companies and all the just plain fun robots you can imagine.

The event is free and open to the public and runs from 1-4 pm. We hope to see you and your robots there!