Archive for November, 2009

OpenSCAD: A Love Story

Friday, November 27th, 2009

Ok, maybe that’s a bit strong, but I’d definitely say we’re dating. I heard about OpenSCAD from the Make Blog, and with a belly fully of thanksgiving turkey I tried it out. I agree with the Make post and the referenced Thingiverse post : In the right hands, designing the right parts, this is a game changer. I played around with it for maybe 3 hours, and was able to generate this:

burr plate

Insane. I’ve been toying with the idea of making a grist mill using burr plates. The main hurdle for me was visualizing all the different angles and how they would interact. I tried drawing one in SketchUp, but after many hours, I threw in the towel. Before OpenSCAD came along I was trying to build the mental momentum to draw the plate in Processing! Seriously. I was going to use their 3D libraries and a TON of math so I could play with a parametrized model.

burr plate code

Speaking of coding, I should also mention that the code to generate the model is TINY. I’ve spread it out and commented it here, but in rough-and-dirty form, the code is less than 10 lines. 10 LINES! I’m free to edit any of the parameters, re-render, and a new model pops right up. Great stuff.

So I’d say there’s a new tool in the tool-box. It’s by no means the only one I’ll use, but certain modeling tasks just got a heck of a lot easier.

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REALLY deconstructing a Doodle Pro

Wednesday, November 25th, 2009

I didn’t really “deconstruct” the doodle pro in the last post. I split the housing apart with a screwdriver, and I didn’t even show pictures! What a gyp. For those of you that are interested in a little more, here you go:

Doodle Pro - Layers Separated

I pulled apart the drawing panel. It looks like it’s made up of two sheets of plastic. One is embossed with a honeycomb, and the other is then fused over-top. I really had to yank to get these apart, so I’m guessing they used some heat to melt them together.

Inside there’s metal shavings and a PUTRID smelling liquid. You know how cherry, watermelon, orange, etc flavors don’t taste like the real thing? Imagine if the same people were asked to make something that smells like feet. That’s the best analogy I can think of: synthetic feet smell.

Oh man, if you could…

Now the million dollar question… could someone DIY one of these? Maybe using a clear plastic mesh and two thin sheets of the same plastic? I think the hardest part would be dealing with the liquid. It needs to be viscous enough to hold the shavings in place, it needs to be opaque, and the plastic layers need to be fused closed with the liquid in place.

If you could make one in the 3′ x 4′ range, the payoff would be huge. Even if you don’t do what I’m thinking with it, it would still make a kick-ass whiteboard replacement.

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Deconstructing a Doodle Pro (a.k.a Magna Doodle)

Wednesday, November 18th, 2009

I’ve been really intrigued by various Etch-A-Sketch automation projects out there (here’s a few.) I’m excited by the prospect of a large, diy, low energy display. I’d love to use one to make a web-synced wall calendar. I can see two major hurdles in the The Etch-A-Sketch route though: You can’t lift the pen, and you need to shake it (or redistribute the powder somehow,) to erase the drawing.

Doodle Pro

I went around and around in my head, trying to figure out how to overcome these issues, when my girlfriend says, “Why not use a Magna Doodle?” Why not indeed! The erasing process is just a swipe of a magnet, and there’s no aluminum dust to contend with. Much easier. (I should mention here that while I have always known this toy as “Magna Doodle,” that’s a discontinued name. Fisher Price bought it and renamed it “Doodle Pro.”)

There’s a wrinkle though. Unlike the Etch-A-Sketch, the Doodle Pro needs the pen to be on the viewer’s side of the screen. That would probably be ok, but ideally I’d like all the display hardware to be hidden from view. What to do, what to to?

Doodle Pro Test - FrontDoodle Pro Test - Back

Well, I got some cheap Doodle Pros today, and upon taking one apart, it looks like that may not be an issue. It turns out that when you draw something on one side, you get a decent negative on the other! So I’m going to try, at least at first, to create a display with the pen hidden from view. The user will see a black (gray, I guess) background with white lines. The lines are a little fatter than I’d like, but there may be some improvements that can be made to the pen that will fix that.

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