Spirograph generator

posted Jul 23rd 2010 12:39pm by Mike Szczys
filed under: misc hacks

The Agnewgraph I can turn out a pretty nice Spirograph drawing. Instead of relying on meticulously acurate CNC hardware, it uses a Spirograph stencil similiar to that business card we’re so fond of. The key to the [Mpark's] design is an analog joystick which is attached to the pen. As the pen follows the plastic guide around, a Propeller microcontroller calculates the angle of travel based on that joystick. These measurements are used to decide how to move the two stepper motors that provide horizontal and vertical motion to the frame. We’ve attached a video after the break just in case our rough description didn’t do it for you.

Comments [8]

tagged: propeller, spirograph, stepper

8 Responses to Spirograph generator

compukidmike says:

July 23, 2010 at 1:33 pm

Nice work, even if it is excruciatingly slow! I have to wonder if the control algorithm can be sped up, or if it’s a limitation of the motors chosen, or if it has a tendency to make mistakes if it goes faster. Regardless, it’s a very unique control method which seems to work well. Now to figure out what else to use it in…

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Concino says:

July 23, 2010 at 1:41 pm

There is gotta be an easier way to do this. How about a bot with 4 unidirectional wheels standing on top of the Spirograph generator with same pen holding mechanism?
I don’t know why but it seems so overly complicated to me at first look.

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AP says:

July 23, 2010 at 1:43 pm

That’s extremely clever.

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Colin says:

July 23, 2010 at 2:25 pm

I agree, way too complicated for it’s purpose. Think of how you used to draw them as a kid, you sorta just made a circle with your hand and let the pen go where it wanted (following the “gear”) so why wouldn’t a robot just copy the same thing?

All in all, though, cool nonetheless.

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Andy says:

July 23, 2010 at 2:42 pm

This is really ghetto with the string and rubber-bands, but still, nice work!

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mpark says:

July 23, 2010 at 5:49 pm

“you sorta just made a circle with your hand and let the pen go where it wanted”—well, that’s pretty much what Agnewgraph does. But you have to be able to follow the pen and adjust your circle. It’s a little harder than I think you think it is.

Can’t argue with the “ghetto” comment though :) Hey, it’s a hack.

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Maya Posch says:

July 25, 2010 at 5:26 am

I have the feeling that this robot may be better at Spiro than I was in the past. I still have nightmares of slipping out of the proper drawing pattern and having my figure screwed up :(

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Peter says:

July 26, 2010 at 11:21 pm

Nice. But does it have to resign from the office of vice-president due to bribes and tax evasion, only to have the rest of the administration crumble under an unrelated scandal a year later?

Should be a feature in the next release, I think.

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