Printing the NASA 3D Models

October 23rd, 2012 (trackback)
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Update: Thinking about it for just a moment, I realized the print quality would likely be higher if I printed in “launch position”. Doing so would greatly improve the wing quality while also, hopefully, improving tail quality in that there would be fewer really small layers (that cause the print head to slow way down, causing blobbing). The disadvantage would be a lot more support material, especially around the engines, and, thus, a potentially difficult, if not destructive, post print cleanup.

And it worked! I only lost one control jet off the back during cleanup, even!

There are more photos of the final printed piece and of the print in progress in my Flickr feed (link goes to a photo in the middle of the set).


I remember watching the first Shuttle launch way back in 1981. If you’d told me then that I’d be casually printing a small copy of the Shuttle on my own personal 3D printer 32 years later, I might have thought you were crazy. Or, at 11 years old, I probably would have have asked, “Why so long from now?”


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NASA has kindly dumped a treasure trove of 3D models available for free download.

Obviously, these beg to be printed. Doing so is a matter of jumping through a couple of file conversion hoops. The files start out as Autodesk 3DS files.

Meshlab can be used to import said files and then export them to STL. You might need to do some mixup after. Using netFabb, I found several errors in the model’s geometry and fixed it. I believe Meshlab can do the same, but I’m not familiar enough with the tool

Slicing for printing is tricky. The models give zero consideration, no surprise, for 3D printing. In fact, they are entirely sub-optimal for printing. For example, the shuttle’s cargo bay is empty, leading to a bit of a support mess, and it would print much better if the wings sat flat on the print bed. Thus, even the simple Space Shuttle model has a curved bottom. You’ll probably want to enable support when slicing. Some of the models, like the lunar landers, are unlikely to be able to be printed using an extruded plastic printer without support material that can be dissolved away afterwords (i.e print in PLA or ABS with PVA support material.

As a first print, I sliced using Cura with 20% infill, 0.2mm layer height, and support material turned on. It actually turned out better than expected!



Posted in 3D Printer, Technology | 1 Comment »

80/50 Yogurt

September 9th, 2012 (trackback)
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When I became sous vide enabled (controlled water bath, anyway, a proper vacuum chamber is on the to-buy list), it immediately dawned on me that a tightly temperature controlled water bath would be perfect for purposefully growing microorganisms as much as for preventing the growth while achieving perfectly done foods.

Roger has long been a fan of yogurt and yogurt is nothing more than milk fermented by a lactose consuming bacteria of, most commonly, the Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus varieties.

And, yes, it has proven incredibly easy, cost effective, and exceptionally delicious to cultivate these bacteria in the milk of your choice using a sous vide rig. Note that you really don’t need a water bath; a cooler, some hot bottles and towels can work well enough.

However, you do need the precision of a water bath to achieve consistent results of the highest quality!

The Recipe

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1. Divide a gallon of milk amongst 5 1-quart Bell canning jars (which aren’t actually 1 quart in many cases — go figure — just divide the milk evenly between them). Lids on loosely!

We use generic organic whole milk, but low-fat works, too. It cannot be ultra-pasteurized (as ultra-pasteurization breaks down the proteins to the point that the bacteria can’t survive. The implications on the healthiness of said milk are quite bad). Raw milk works beautifully, but is expensive. I’ve been meaning to try a mix of sheep and/or goat with the cow’s milk.

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2. Place in an 80℃ water bath for ~2 hours (long enough to heat the milk thoroughly to 80℃ for at least an hour).
3. Cool milk to 50℃. I find it easiest to scoop out the hot water and replace with cold water to bring the temperature down rapidly.

I usually set the target temp of the water bath to 48℃. By doing this, the residual heat from the milk will leach out into the water bath and you can tell when it is stable when it holds steady. You can inoculate and bring the temperature back to 50℃ simultaneously (48 would be a fine temperature to incubate the cultures). The key is to make sure the milk is solidly below 55℃ before inoculation, otherwise you’ll run the risk of killing off the live cultures!


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4. Stir in one tablespoon of the plain flavor of your favorite brand of yogurt into each jar. Place lids back onto jar loosely.

You can use previous batches to inoculate new batches, but it is generally recommended that you refresh with new yogurt every few batches. Honestly, I’m not sure how much this matters. It’d seem that as long as you store your live culture yogurt properly, you shouldn’t have any more of an issue than one might with, say, a sour dough starter. Mostly, I end up “starting over” with store bought plain yogurt simply because we eat the previous batch so quickly and we forget to preserve enough to start the next batch!
5. Leave in the water bath for at least 12 hours and up to 24 hours (maybe even longer). The longer they are in the bath, the more greek-like sourness to the yogurt. I usually target 18 hours, maybe 22, and everyone in the family eats the stuff like crazy.

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6. Tighten the lid and submerge in ice water to stop the bacteria from continuing reproduction as the temperature falls (more below). You should hear a “pop” as each jar seals itself.

7. Refrigerate. Keeps for at least three weeks.

You’ll get a bit of whey on some jars, some more than others, I typically collect the whey and use it in bread making.

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Posted in Food, Sous Vide | 1 Comment »

Whoah! Arduino goes ARM on the cheap & Arduino AVR Gets Really Tiny (on the cheap)!

September 5th, 2012 (trackback)
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For the Teensy Blaster, I used a Teensy v2.0 board from PJRC. It is a tiny board containing a not-so-limited AVR chip (32K of flash, >2K RAM, 1K of EEPROM, and a slew of I/O pins) and a mini-USB port with the ability to be USB bus powered. Tiny. Versatile. And cheap at $16/board! $24 nearly gets you nearly 4x the memory and nearly doubles the I/O ports.

Today, I ran across Teensy v3.0 on Kickstarter. In pretty much the same sized package, the Teensy v3.0 features a 32bit ARM Cortex-M4 board with 128K of Flash(!!), 16K of RAM(!!), 2K of EEPROM, and a slew of I/O options. If that weren’t enough, it includes support for IR, a high quality audio interface, an optional real time clock, 4 DMA channels, and support for touch sensor inputs. And more. Much more. Holy cow! Truly, a nutty amount of computing power in a 1.4″ x 0.7″ package!

And it can be used from both Arduino and C.

So, yeah, funded. No brainer.

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Then, at the thank you for funding this project page, there is a thing you might be interested link that leads to the Digispark.

Wait. What? A board barely bigger than a USB connector that features an Arduino compatible CPU with multiple I/O pins, 8K of flash, PWM on 3 pins, ADC on 4 pins and many many different shields?!

For $8-$10 / board?!

Sign me up! (And I did!)



Posted in Make, Technology | No Comments »

Arduino on Mountain Lion

August 21st, 2012 (trackback)

In my “spare” time (hah!), I hack on Arduino a bit. Mostly because there are tons and tons of 3rd party libraries that make hacking up a hardware solution mostly a bit of soldering followed by gluing together some pre-made software bits. The Arduino IDE is Java based and… well… not terribly awesome (to be fair — it isn’t awful, just quite lacking beyond the basics).

With the release of Mountain Lion, most Arduino installations were broken. Fortunately, this can be fixed by grabbing the latest bits from here and there.

  • Grab the latest Arduino.app for Mac OS X
  • Run it and it’ll insist on installing the latest Java VM. Do so.
  • If you use Teensyduino, grab the latest installer and install it. If Mac OS X (rightly) complains that the software is from an unidentified source and can’t be opened, you can ctrl-click on the installer, select “open” and it will present the option to bypass the security check. Do so, but not without a bit of misgivings.
  • Install the latest FTDI driver.
  • If all went well, you should see the device show up in /dev/ as something like /dev/tty.usbmodem12341.


    Posted in Mac OS X, Make, Software | 4 Comments »

    Amazon: Playing with an iPad

    August 4th, 2012 (trackback)
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    We spent a week at the end of June on the Amazon River in Peru with International Expeditions. Fantastic trip, more on that in a later post.

    One afternoon, we visited a village — Nueva York — along the Amazon. We spent some time with the children of the village, learning a bit of spanish and teaching them a bit of english (Head! Shoulders! Knees and Toes! Knees And Toes!).

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    One of our guides asked me to show the kids my iPad as they had never seen anything like it before. It took a moment, but they were enthralled. The big hits were Photo Booth and a simple finger painting app.

    It was quite gratifying to see the kids take to the iPad and start using the apps so naturally. They quite quickly learned how to change and control the effects in Photo Booth. Including taking their own pictures, as seen at the right.

    Of this wonderful experience — the kids were fantastically good natured and the adults were warm / welcoming — there were two standout events that I shall relay, one purely cultural and the other just flat out cute.

    When I first launched Photo Booth and showed it to one child, I was a bit surprised by the reaction. It was sort of, “Well, that’s neat.. but.. meh, weird pictures of a person isn’t that interesting”. When I turned the iPad so his friend could see, the second kid’s reaction was the same, but the first child completely lit up with laughter as soon as the second kid’s face was on screen! Then the same happened when I rotated back to the first child.

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    As it turns out, there are pretty much no mirrors anywhere outside of, maybe, a hand mirror or two. Children really don’t see themselves on a regular basis save for on the back of a digital camera in the hands of a tourist (we were encouraged to always show them any pictures we took). Thus, seeing “self” just wasn’t very interesting at all.

    Once I suspected this was the case, I saw this same behavior with pretty much every child who saw Photo Booth for the first time!

    The really cute event happened when I was showing a little girl — maybe 6 or 7 years old — the finger painting application. It took her a second, but she got into it and had quite a bit of fun making a smily face. I showed her that the color could change and then left the color picker (a little grid of color swaths) on the screen for her to pick.

    She thought about it for a moment.

    Then carefully tapped light blue.

    Then looked at the tip of her finger to make sure the color was picked up.

    Disappointed that her finger wasn’t blue, she tried again with yellow. Same thing.

    Then I showed her that the color really did change and she was happily drawing away again. Still, every new color required a finger tip inspection…

    Neat folks. I hope to visit again.







    Posted in Life, Travel | 3 Comments »

    Aerogarden 2nd Run; With Custom Built Pieces

    May 14th, 2012 (trackback)

    After nearly 5 months, the first run of herbs in the Aerogarden were finally tired to the point of no longer useful (I started with AeroGarden Gourmet Herb Seed Kit (6-7-Pod)spacer and it worked really well — way more than $18 worth of fresh, tasty, results).

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    One of my goals with the Aerogarden is to gradually replace all the pieces until I’ve effectively created a homebrew Aero-Hydro solution that will eventually integrate with our atrium’s pond (fish poo fertilizer FTW!), use LED lighting, and, hopefully, be an interesting conversation piece.

    The next obvious step was to replace the seed pods and baskets. The seed pods/baskets are the one piece that needs to be replaced with each planting. The baskets — white plastic things that fit in the holes on top of the Aerogarden — can be mostly reused, but the original design is obviously optimized for cost, not effectiveness (they don’t actually fit correctly in some of the holes!). The seed pods, themselves, are little bundles of seeds in growing medium; Aero’s are good quality, but relatively expensive and the seeds are of unknown variety (i.e. generic curly parsley and not some particular strain).

    At left is the current phase; seed pods and growing medium replaced with Basil sprouts showing some signs that it is working!

    Read the rest of this entry »


    Posted in Gardening, Technology | 3 Comments »

    3D Printing: Oh, The Tuning We Shall Do.

    March 25th, 2012 (trackback)

    After a while with the Ultimaker, a series of notes on the various things one can do to tune the 3D printing experience.

    Some of this is specific to the Ultimaker, but most of it is not. Much of this is personal preference and, frankly, there is probably some stuff in here that is wildly sub-optimal. But, hey, it has worked for me and it worked better than it did when I started.

    I.e. feedback and corrections are quite welcome!

    First, a note on consumables. I have stuck with PLA (polylactic acid) exclusively. It is a plant derived material that requires a lower tempera

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