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Rotary Encoding

Rotary Encoding

For an upcoming project we want to use rotary encoding with optical sensors, so I did a bit of hacking testing today…

I’m using two photo interrupters mounted on breakout boards with 220 ohm resistors.

For an encoding disk I searched for a suitable SVG file and found this blog post, which just happened to have a link to a perl script (of course!) to generate encoding disks. A little Inkscape magic and I printed out a disk to test with.

I should note that my original plan was to use the Silhouette Cameo to cut the slots in the disk, but the paper version actually worked fine for testing. In the final piece we’ll probably use a piece of laser-cut acrylic.

With my encoding disk ready I hot glued it to a bolt and chucked it in the drill. This gave me an easy way to vary the speed and direction.

Rotary Encoding

I grabbed the Encoder_Polling library and used the counter example and that was about it. I could now see if the disk was spinning and in which direction (by looking at the numbers increase or decrease.)

I really thought I’d need to mount the photo interrupters more precisely, but I pretty much left them hanging in mid-air supported by wires on a breadboard and it worked fine. (Maybe I just got lucky?) There’s a lot more code to write, but this was a good start.

Oh, if you want to learn way too much about reading rotary encoders with an Arduino, visit the Reading Rotary Encoders page and set aside a few hours…

Note: I also found an online encoder wheel generator.

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Digital Wonderments

Mounting Plate

It seems that when I ordered parts from Inventables, I forgot one thing! Seems I didn’t have this Motor Sub Plate that I needed.

Mounting Plate Plans

Luckily Inventables provides technical drawings and CAD files, so I grabbed the PDF file and opened it in Inkscape…

Mounting Plate 2D

I had to delete a lot of the measurements on the drawing, but when I was done I had a file that I could easily laser cut. But alas! I have no laser cutter at home… No worries, a bit more work on the file (changing all the curves into segmented lines, connecting all the disconnected lines) and I was able to save a DXF file…

Mounting Plate STL

And the DXF file was easy to import into OpenSCAD and extruder as a 3D (well, 2.5D) file and get an STL file, which can be printed on a 3D printer, which is what will be happening in a few minutes…

Digital Fabrication… it’s a thing.

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3D Printing with Wax

Wax Ring

The folks from Solidscape dropped by the DCRL at UWM to talk about their 3D printers that can print with wax. These are typically used in the jewelry industry for lost wax casting, but also used in the medical, dental and engineering fields.

Wax Ring

The resolution of the prints was simply amazing. They’ve also got some unique things that their printers do, like milling the build plate flat before each print.

Wax Ring

Their machines are not cheap, starting at $25,000 and going up to $55,000, but the quality is pretty amazing, and depending on your needs, that price may be cheap.

Wax Turbine

Obviously lost wax casting in metal is a prime use of these pieces, but there were a lot of other applications mentioned, including multiple methods of creating silicone molds.

Wax Turbine

The details was pretty amazing, and not even in the same ballpark as what I’ve seem from any FDM printer. If you get a chance to see the output from a Solidscape printer, do it. It’s pretty impressive!

Wax Head

Wax Head

Wax Tire

Wax Tire

Note: Frankie has better photos and more info!

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Grace Choi: Hacker

Grace Choi

Grace Choi is pretty awesome. She’s come up with a way to print makeup using a hacked inkjet printer. Yeah, what? You can check out this HOW TO, or just check out how she plans to disrupt a huge and extremely profitable industry.

I found her demo to be a bit unpolished from the software end, but she seems to know that there’s a great opportunity for developers to fill that gap.

I’m not really into makeup, but I am into 3D printing, and disrupting entire industries is definitely an interesting proposition. Here’s a bit of what Grace had to say that really illustrates the kind of person she is.

“One person alone can’t disrupt this entire beauty market,” Choi says. “Together, as a community, we can disrupt it. I’m willing to take a hit financially because my number one motivation is for change. This is a very important social mission for me. I think of Mink as an educational tool for kids, and one that can get girls interested in technology. I don’t need to be on some billionaires list. I’m aggressive and I’m going to make this happen. Before I die, this [beauty revolution] will happen.”

And if that’s not enough, there’s also this one:

“The makeup industry makes a whole lot of money on a whole lot of bullshit. They charge a huge premium on something that tech provides for free. That one thing is color.”

Definitely one to watch…

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A Better World

Earth

Yesterday I was talking to Caitlin (a fellow Grad Student at UWM) when two Undergrads approached us, and asked if they could ask us a question, and that question was “What gift would you give to the next generation?” I tried to answer something along the lines of “A better world” but I wasn’t very articulate. I thought about it a bit more, and here’s my answer.

I want to give the next generation a better world. A world with more understanding, and more knowledge. Not just information, but real knowledge. Useful data that can be used to make informed decisions. A world with less problems. Solutions to existing problems so that the future generation doesn’t have to worry about them.

I was thinking about the idea that you should leave your campground better than you found it, and stumbled upon The Boy Scout Rule (applied to software in this case, but it doesn’t matter.)

The Boy Scouts have a rule: “Always leave the campground cleaner than you found it.” If you find a mess on the ground, you clean it up regardless of who might have made the mess. You intentionally improve the environment for the next group of campers. Actually the original form of that rule, written by Robert Stephenson Smyth Baden-Powell, the father of scouting, was “Try and leave this world a little better than you found it.”

I’d highlight “leave this world a little better than you found it.” (And yes, I marked the “try and” in the above quote as deleted because I’m trying to leave this bit of wisdom better than I found it. :)

That’s it. It should be that simple: Leave this world a little better than you found it.