kellbot

Nov 302011
 

This time of year our laser gets pretty busy, so we’ve opened up an additional laser night on Wednesdays.¬†Tonight through December 21st, come by on Monday or Wednesday from 7:30-10:30 to fire the laser!

 

And another thing…

Because it’s such a popular time of year for lasing, we ask that you prepare your cut files so they can be broken up into smaller batches. That way instead of one person monopolizing the machine for hours, we can rotate through. So if you have an army of 100 Christmas ornaments to make, prepare your file so they can be cut in 2 sessions of 50 or 3 sessions of 33.3333.

 

Nov 222011
 

We’ve had a few knitting machines rattling around the space over the years, but when fellow gadget lover Josh dropped off the lace carriage for our Toyota K747 knitting machine, I figured it was time to take it past basic stockinette stitch and explore the machine’s punch card mechanism.

Like most decades-old machines, a layer of dried oily gunk coated many of the moving parts. There are also a few broken/missing pieces. I’m in the process of cleaning / fixing the machine, and trying my best to document it as I go along. I got a hold of the K747 Service Manual, and started diving in. It’s oiled up now, and the next steps are to repair the broken needle selector and write up a program to generate punch cards for the laser.

Busted

¬†The picture above shows the offending broken lever. These 12 little blue levers tell the machine which needles to push out for the patterning, but lever #3 is broken so it never engages. Getting in to replace it is a bit daunting, in fact just getting to that lever in the first place was a bit of an event, I’m going to attempt to fix it with Sugru first. If that doesn’t work, then I’ll be makerbotting a replacement and praying I can get it all back together after dismantling it.

Since the machine is loud and takes up space I generally only work on it during the day when there’s more room, but if there’s sufficient interest I’d be happy to demo it at an upcoming craft night.

You can see more shots of the inside of the machine over on my blog: Knitting Machine Teardown Part 1 and Part 2.

May 162011
 

I’m Kellbot! I’m a member of NYCR, and I love gaming.

My friend Katherine and I have been working like crazy on a game project for the last few months, and we’re thrilled with what we’ve accomplished so far. Now, we’re trying to bring it to an open beta while making it as fantastic as possible. We’ve started a Kickstarter campaign to get us there.

City of Epic is an RPG based around real-world exercise. Rather than get all TL;DR, I’ll let this “high quality” video explain it:

If you like some combination of gaming, fitness, and awesomeness, please consider donating!

Sep 172010
 

It's hard to imagine that 15 years have passed since Hackers came out. It seems like only yesterday we were grimacing through the bad acting and worse "technology" references that Hackers brought to life.

Whether you love or hate the movie, everyone can agree that the 15th Anniversary Party is the perfect excuse to dress up in ridiculous looking retro clothing and drink with a bunch of other wannabe cyberpunks. In other words, it will be a typical night in Williamsburg.

More information on the party Kickstarter Page

Jun 202010
 

Meta Lego

In need of a better storage/organization scheme for my Lego collection, I made these meta legos: boxes that look and function like legos which hold my legos. The full details are available on Kellbot! but, long story short, I used OpenSCAD to create plans for boxes in any brick dimensions I like.

If you haven’t used OpenSCAD, it’s super handy for generating .dxfs for laser cutting, and is great for designing parts to be MakerBot’d as well. I’m teaching an Intro to OpenSCAD class next weekend, it’s only $25 and no prior programming experience is required!

Plans and more details can be found at [Kellbot!]

Jun 172010
 

Want to learn to create 3D models, but find the user interface for most 3D modeling programs too infuriating? OpenSCAD may be for you! And we're teaching a class on how to use it on Sunday, June 27!

OpenSCAD is "The Programmers Solid 3D CAD Modeler." Rather than learn tricky user interfaces and navigate seemingly endless obscure menus, OpenSCAD uses a simple scripting language to generate 3D models from either existing or new 2D drawings. We'll start in 2D (great for creating designs for the laser cutter) and move into 3D modeling (perfect for MakerBot!).

A basic understanding of computer programming is helpful but not required. Sign up at EventBrite today!

May 302010
 

It was only after hours of searching that I finally came up with what I was looking for: a way to take a polygon mesh (OBJ or similar) and convert it into a blueprint for building LEGO sculptures.

Don't get me wrong, there are tons of tools out there for LEGO CAD. But strangely none of them mention being able to go from a mesh to a LEGO layout. It's surprising, since it seems like such a natural fit. The rise of 3D printers has rejuvinated interest in voxels, voulmetric pixels, and as evidenced by all the LEGO sculpture artists we seem to be in a golden age of LEGO. 

Armed with Blender and a giant LEGO collection, I set out to get the computer to do the hard work for me. I used Blender, graph paper, a pencil, and of course lots of LEGOs.

Step 1: Voxelizing a Utah teapot

Let me preface this by saying that the Blender UI is not for the faint of heart. I took classes on Rhino and 3DSMax in college, and thought to myself "how different could it be?" The answer: very. If you're new to blender, don't fear the manual. You're going to need it, particularly the parts on installing/using python scripts.

To voxelize the teapot I used a script called Add Cells which covers the surface of any object with any other object. First I imported the teapot, and scaled it up a bit. Then I created my "fundamental unit" of LEGO. LEGOs have an aspect ratio of 6:5, so I created a 1×1 LEGO, a 0.6×0.5×0.5 rectangular prism in Blender.

Selecting both the teapot and my 1×1 lego I ran the Add Cells script (go to the Scripts menu –> Add -> Cells). I chose the Teapot for my object to be voxelized and the 1×1 LEGO as my voxel model.

Tada! A blocky teapot!

Step 2: Graphing each layer on paper

In order to make the build process easier, I went through layer by layer and drew a map of each layer on graph paper. This way when building with LEGOs I could shade in with a pencil each voxel I'd built. It sounds redundant, but when things all start looking the same after a few minutes and something isn't lining up, it's very helpful.

To see one layer at a time in Blender I went into Sculpture Mode, side view, and used ctrl+shift+right mouse to select and hide all but the layer I wanted to see. Then I switched to Top view and copied the layer onto my graph paper. By the end I had a sheet of paper full of wobbly circular outlines.

Step 3: Building it with LEGOs!

The completed model uses 244 LEGOs, many of which are tiny 1×1 and 1×2 bricks. The model is hollow, but the walls need to be fairly thick to be able to support the top. As it is I probably should have made things a little thicker; putting the last two layers on was a delicate operation.

I built each layer sequentially. There were a few overhang pieces near the bottom which I had to append to the layer above them, since they couldn't anchor to anything below.

Overall the project took about 4 hours, with a break in the middle for breakfast, church, etc.

Total LEGO count for the project was 244 individual bricks, distributed thusly:

  • 44 2×3 Bricks
  • 46 2×2 Bricks
  • 58 2×4 Bricks
  • 27 1×2 Bricks
  • 17 1×3 Bricks
  • 8 1×4 Bricks
  • 8 2×2 L shaped Bricks
  • 33 1×1 Bricks
  • 1 2×8 Brick
  • 1 2×6 Brick
  • 1 1×8 Brick
     
May 132010
 

I ordered a miCoach, which is the Adidas version of the Nike+. When it gets here I plan on opening it up to play with the data, but in the mean time I started with some better-travelled exercise bits and bytes: WiiFit body test data. Starting with Jansen Price’s excellent blog post on the subject, I slowly worked through the data and wrote a python script to interpret the binaries and save them to a CSV. I was able to generate the nice graph above. There was a lot of trial and error, but here’s an overview of the process:

  1. Copy Wii save game data to the SD card. This is done from Wii Options > Data Management > Save Data > Wii
  2. Find the save game data on the card. It’s in something like ‘private/wii/title/RFPE’, although different regions may have slightly different codes. RFPE is the code for WiiFit Plus. Copy the WiiFit data.bin file from the SD card to your local machine.
  3. Decrypt data.bin. This is explained pretty well here. To create the keys I ended up creating text files with the hex string for each and then using “xxd -r -p sd_iv_hex sd_iv” et al to save a binary version. If you’re getting “MD5 mismatch” errors, you probably saved the keys incorrectly. If you aren’t sure, check the file size. They should be 16 bytes each.
  4. Run the decrypted RPHealth.dat through a parser (I wrote one in Python for this)
  5. Run the CSV through your favorite graph generation library. I use flot because Google Charts don’t handle dates very well.

More details, including the source for the Python script can be found over on my blog: Kellbot!

Apr 132010
 

I spent a decent portion of yesterday on the laser, prototyping a tiny embroidery hoop for (duh) tiny embroidery. I'm pretty happy with the results. So much in fact that I've decided to start offering tiny embroidery kits along side my tiny dinosaur kits.

The embroidery hoop is made from laser cut acrylic, and the rubber band provides tension to keep everything in place. The whole thing measures 1.5" across, a standard sewing machine bobbin is show for scale in the picture above. I actually neglected to save the cut file (oops) but it's pretty simple: two concentric rings (0.2" wide), with the outside diameter of the smaller ring being 0.05" smaller than the inside diameter of the larger ring. The large ring has a "nub" on the side for the rubber band, and is split down the middle on that side.

There's about a 1" diameter working area. I used 28 count aida fabric, which gave me approximately 28 "pixels" across to work with. Chris helped me design a cupcake chart for counted cross stitch. It uses 7 colors: white, red, light pink, dark pink, pink, grey, and light grey. It's a nice portable project because it fits in your pocket. I've listed a kit for sale on Etsy and may bring a few down to Spring BadaBing in Richmond, VA this weekend.

Here's the chart for your cross-stitch pleasure:

Mar 132010
 

Since everyone else appears to be at SXSW, I suppose I’ll have to step up for today’s March Madness. I bring you: a screen scraper for retail products on ecommerce sites.

While I’m hardly the first person to write such a tool, finding useful examples or libraries among the hundreds of pages of screen scraper spam has proven difficult. I ended up writing one from scratch in PHP using the DomDocument object.

The goal of the scraper is to come up with the product title, price, and 3 most likely product photos from any given product URL. In order to make it a bit faster (it’s pretty painfully slow), I attempt to filter out images which are obviously not product photos (those which are very long/tall, those which are not displayed in the browser). Then for a bit of extra fun, it sorts the image array by it’s “likeliness” to be a product photo. Obviously it needs some refining to actually be useful.

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