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Turntable Drawing Machine

Sketches

As previously mentioned, I’m working on a new drawing machine, and it’s based on a turntable. I’ve included some of the sketches here, as I continue to explore a few ideas.

Sketches

There’s a number of aesthetic choices to make in the design of this thing, including the material. Right now I’m focusing on wood for the majority of the build, but may also include some acrylic (which may allow for some LED lighting) and metal. I’d consider Alupanel, as that stuff is pretty nice, but it’s also a bit pricey, especially since I’d need a piece that is 19″ x 15″.

Sketches

There’s also the mechanical build to deal with. I’ve got a good idea of how that will work, and I should be prototyping the spinning platter mechanism this week. I have semi-working Arduino code already, but I’m still contemplating direct drive versus a belt system. (I have all the parts, just need to start experimenting.)

Turntable

I stopped by Bliffert Lumber last week to grab some 1/4″ Baltic Birch plywood, and I cut the top panel and turntable. These may just serve as test pieces and not final pieces, but it’s something to start working with. I used a 90 watt laser cutter as it’s quick and easy. I do have a 1/4″ end mill coming in this week, so I can cut 3/4″ wood on the big CNC router if needed. It’ll all depend on material and time. (This needs to be completed in about a month.)

Hopefully I can start working on the arm mechanism by next week, as there’s a few tricky bits involved there. I’m not sure if I will use limit switches, a servo, or make the pen placement a manual process. Hopefully a prototype will come together soon and answer some of those questions.

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Laser. Cut. Files. (Part IV)

It’s been a few years since I’ve posted about laser cut files, and by that I mean, the files I prepare to be used for laser cutting, so I thought I’d do an update.

Right now I typically use a few different laser cutters in the Milwaukee area. At Milwaukee Makerspace there’s a 60 watt ULS and 50 watt ULS, but using a Windows PC with CorelDraw for control, and at Brown Dog Gadgets there’s a 90 watt Chinese laser cutter using CorelDraw (and LaserCut 5.3) though it seems to be a much newer version than used at the Makerspace. I also use a 40 watt Epilog Zing at UWM’s DCRL. The Zing uses Rhino instead of CorelDraw, which may sound weird, but it works.

I’ve got a file workflow that can work with all of these machines… which I’ll explain below.

Panel Mount

Here’s what my vector art looks like in Inkscape. You’ll notice that the inside lines are blue, and the outside lines are black. This is so we can set a manual cut order for machines that don’t automatically cut inside lines first. (Some software is smart, and always makes inside cuts first, other software… is not.)

lcfiles02

I should note that while doing the design work I may end up with multiple layers. Often I’ll use layers to hold pieces or revisions of a design. For our final file though, we want a single layer.

Let’s pretend my design file is named “Panel Mount.svg”, and it has more than one layer. When I’m happy with my work, and have all the things that will be cut on one layer, I’ll save that file, duplicate it, renaming the dupe to “Panel Mount LC.svg” and then open that file. My original design file (Panel Mount.svg) is now safe and sound, but my new file (Panel Mount LC.svg) is about to get altered.

Files

I usually set all the objects to have no fill. This may not be required for all workflows, but I like to be consistent. (Oh, one more thing… you may need to “convert objects to paths” to get things to work like you expect them to in LaserCut 5.3)

Files

For the stroke I’ll set the outside lines to black… (This may be different depending on your laser cutter software.)

Files

And I’ll set the inside lines to blue. Again, this may depend on the laser cutter software & driver you use. Some allow you to set the order of colors, and some may not. If I need more colors I can use red, green, etc. (Also, if you’re working with a laser cutter operator who is colorblind, ask them what colors they prefer.)

If you want to selectively cut things and only have one color, you can use this trick: Load the file into the laser cutter software (CorelDraw, or whatever) and delete the parts you don’t want to cut, then cut. Then “undo” until all parts are back on the screen, then delete other parts, cut again, and repeat. Not the cleanest method, but it totally works. Don’t move any parts, though you may have to ungroup them, and obviously do not move the thing you are cutting.)

Stroke 0.03mm

Once I’ve applied all the colors, you can select everything and set the stroke. I set it to 0.03mm. This should set it to “hairline” when you import it into CorelDraw. Rhino also seems to do the right thing. If your stroke is too thick it can cause issues. (Always check for the lines to be set to “hairline” after you import your PDF.)

View

After you change the stroke the lines may appear very faint. If you can barely see them switch the Display Mode to “outline” which makes every stroke appear a black and sort of beefs up the lines.

At this point I run down the checklist…

  1. The file has one layer (If it had more, I duped the file and then adjusted the dupe to have just one layer.)
  2. The file has all objects set to no fill.
  3. The file has all objects set to 0.03mm stroke.
  4. The file has different colors for inside and outside cut lines.

Obviously you can do all the file prep stuff (line colors, stroke, etc.) in your master file, and then dupe that one and delete any extra layers. The order isn’t the most important thing here.

PDF Export

Once we’ve made all the changes, we can save our “LC” version of the file. After that, it’s time to use the File menu’s Save a Copy… command to save it as a PDF file. Note that “Convert texts to paths” is selected. This should create a PDF that does not rely on any fonts being installed. If you used text in your file, this is helpful. It does however mean that you cannot edit any text when you import the PDF into other software, as it will have been converted to lines.

PDF

Oh, one more thing! Some older versions of CorelDraw seem to have issues importing PDF files created in Inkscape. On Mac OS X, I just open the PDF that Inkscape created, and export it. It somehow fixes the PDF so CorelDraw likes it. Whatever… it works, so I do it!

Simple Dual Axis Solar Tracker

(BTW, the piece I used an as example was for the Simple Dual Axis Solar Tracker from Brown Dog Gadgets.)

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More Rotary Encoding

When last we discussed rotary encoding, it was all experimental. Since the project (which will eventually be revealed) is complete, I figured I should share a bit more about the exploration and final solution.

Encoding Disk

I moved from printed paper disks to laser-cut disks. I cut some 3mm Baltic Birch plywood at Milwaukee Makerspace. They worked well, but since I was hoping to get more steps/resolution I continued with the paper prototypes as well.

Encoding Disk

The one in the photo above was a bit too fine… too many steps. The more steps the more precise the alignment has to be, and the more chance of errors.

Gap

We had some concerns about a disk spinning between a U-shaped sensor with just a few millimeters on each side, so rather than just go with the GP1A57HRJ00F Photo Interrupter, I started experimenting with the QRD1114 Optical Detector / Phototransistor as an alternative.

Sensors

The idea would be to use a wider disk and instead of it spinning between two pieces, it would have the encoding stripe on the edge, and the sensors would be on the outside of the disk. Back to the breadboard! The QRD1114s require a pair of resistors to work properly, so I wired it up and did a few tests and things seemed to work.

Encoding Strips

My first tests just involved sliding a piece of striped paper across the sensors, but I needed a real disk. I used the laser cutter at Brown Dog Gadgets to cut some disks from 1″ pink foam, and also from 1/4″ foamcore board. The pink foam actually ended up with concave sides due to the melting power of the laser, so I used the foamcore board pieces stacked up.

Stripes

Math time! How long of a strip do we need to wrap around the disk? Well, you can determine the circumference of a circle if you know the radius or diameter. Hooray for math! Above is a letter size file that I could print on a laser printer to produce the stripes I needed. The thin line on the right side was used for alignment since I had to use multiple stripes to wrap around the disk.

Encoder

Here’s a sneak peek of what the final disk looks like. There’s a few more steps before we got this far though, so I’ll continue the story next time.

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I like to sketch!

Sketch

Graduate reviews are done, and I got feedback from faculty on my current work. I was a great opportunity to gain insight into how others view the work I do. Typically these sort of things help reveal ideas that you don’t think about while making the work, or bring up new questions in regards to why you make specific choices.

One of the interesting takeaways from today was when a few of my pieces were called “sketches”. If you think about a sketch, it’s defined as “a rough or unfinished drawing or painting, often made to assist in making a more finished picture.” Many of the pieces I created are experiments, or explorations of ideas. They’re often not highly crafted pieces. I appreciate craft and people who are skilled at creating beautiful objects, but I often think I don’t have it in me to do that sort of thing.

I thought more about sketches, and the fact that in the Processing and Arduino worlds, the programs are called “sketches”. As I understand it, this was done specifically to appeal to artists and creative people who didn’t have a background in computers. Tell an artist they are going to write a computer program, and that’s a frightening proposition, but tell the same artist they are going to create a sketch and that’s an achievable goal.

I sketch with physical things…

That’s today’s revelation. Many of the things I make are real-world sketches. The physical manifestation of an idea. Often there’s an immediacy to the creating of the thing, but not always. I tend to work in two ways. The first is a reactionary mode, where I have an idea and act on it immediately. I start building without too much thought, and see what the process and the piece reveal. The second method involves thinking, designing, and prototyping as an iterative process. The pieces created from the second method are often more polished, but both methods produce valid work, and the reaction to each kind of work may be equal (meaning, people don’t always gravitate to the work that had more initial thought or took more time.)

Oh, I also want to drop the other definition of sketch here, “a short humorous play or performance, consisting typically of one scene in a comedy program.” This also relates to some of my work, but I’m going to leave that exploration to a future post.

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A Brief History of Drawing Machines

Pablo Garcia

Machine Drawing

I stumbled upon this project titled Machine Drawing Drawing Machines by Pablo Garcia a while ago, and then I found this great video of a talk he did at MIT about the history of drawing machines.

Pablo Garcia

Technology and art have always come together in some way…

It is a long video, and it was an hour into it before I realized Pablo was the guy behind the NeoLucida Kickstarter. I’m not as much a fan of drawing aids as I am machines, but there’s a ton of great info in the video.

There’s also a DrawingMachines twitter account worth checking out, as well as Pablo’s account, and his web site at pablogarcia.org

The video revealed a lot about machines and drawing that I’ll be thinking about for a while, especially in relation to my own work and views on these things. Good stuff!