Adjustable Spirograph

[Blakbird]

Thanks for the efforts Philo and Alasdair. I have been compiling the updates into a "master" file so we have the most current version. I will keep over-writing my posted file with the latest.

Alasdair, you only posted arm3.ldr, but it uses arm1 and arm2 which were not posted. If you can also post the plotter table, I'll add them to the file.

[Lakop]

That's why I love lego!

H

[legolijntje]

Nice work everyone!

[Alasdair Ryan]

File downloads for arm file1 file 2 file 2b.

Here is base file, in current stepping state. I am somewhat stuck, I can't find a good building sequence for the last element I stepped (see comment in file for location). Any Idea?

I think you will need to make sub models,also ideally you should have dashed lines to show the alinement of certain parts, that is certainly what I would have done.

Alasdair, you only posted arm3.ldr, but it uses arm1 and arm2 which were not posted. If you can also post the plotter table, I'll add them to the file.

Its a pleasure to help.

I have posted links to the sub models of the arm above, there will be sub models of the plotter too so once that has been done I will post the links.

Edited November 1, 2013 by Alasdair Ryan

[Philo]

I think you will need to make sub models,also ideally you should have dashed lines to show the alinement of certain parts, that is certainly what I would have done.

What I am looking for is a buildable sequence, not the way to display it... Can't figure out how to build this part without bending things!

[Alasdair Ryan]

What I am looking for is a buildable sequence, not the way to display it... Can't figure out how to build this part without bending things!

Oh,actually in the table module it uses 4 s long axles instead of axle pins.

[Blakbird]

What I am looking for is a buildable sequence, not the way to display it... Can't figure out how to build this part without bending things!

Yes, there is a difference between adding building steps and creating instructions. At this point I'm just looking for the building steps. I'm pretty sure I can already build it using the file as it stands now, but it would involve a lot of thought in certain places to get the order worked out. That's what we're trying to accomplish in advance. Alasdair has taken it one step further and added arrows and other instruction details.

[JM1971]

I did have a bit of a daft idea once, video yourself taking it apart and then reverse the video, might help lol?

[Blakbird]

I did have a bit of a daft idea once, video yourself taking it apart and then reverse the video, might help lol?

A lot of photo instructions are done that way. It works very well.

[Alasdair Ryan]

I have sorted through the plotter table,you can find the files below.

I did not add any buffer commands to any of the files,but did step the main file.

I will not get any more time until the end of next week to look at doing another one,so feel free to carry on with out me.

plotter 1

plotter 2

plotter 3

plotter 4

plotter 5

[DrJB]

I built it and made some changes to the frame to make it 'kid-proof' ... Somehow a 12T gear broke. Went ahead and 'stiffened' the frame and replaced few parts. Sturdier design now. All New/Replaced parts are in WHITE. Broken gear is in yellow. http://www.brickshel...ry.cgi?f=535841 EDIT: Corrected some of my original wording.

Edited November 4, 2013 by DrJB

[Lego Otaku]

Which 12t gear? single bevel is pretty thin and usually breaks under high torque. The larger double bevel is usually hard to break unless the gear had a defect like crack or bad mold.

[legolijntje]

Actually, I don't see any reason why something would break in this model. There aren't any high torques or am I wrong?

[PG52]

No, there is no high torque anywhere... Mine ran hours long, and three days long at Fana'briques without any gear broken.

Your 12t should have been cracked before...

Thanks to all for your work, I'd be unable to make all this, it's fantastic !

[JM1971]

Any stress would show in the drawing I would think, bumps and such, but in the video its very smooth.

I just thought, there are not many mocs that create something, I think this is why people are so eager to build it.

[DrJB]

Agreed, there is no high torque, but possibly some parts were not 'assembled' correctly. That is why I added some 'bracing' to stiffen the frame at some key locations. Also, I used a 'new' 12T gear on a 5.5 axle and it slipped. Possibly, when it did that it locked one of the transmission paths and the gear broke. In the LXF file posted above, the gear that broke is in yellow, and all new 'bracing' is in white. My kids are having a blast trying all sorts of combination. We found 2 more variables we can 'play' with, the radii at which the two suspension parts are attached, and the tilt angle of the pen (how it is attached). The latter can yield very different patterns. Fantastic MOC PG52 ... Thank you for sharing.

Edited November 4, 2013 by DrJB

[CP5670]

This is a fantastic model, especially the nonlinear but smooth motions of the drawing arm. I would like to build it too.

I just thought, there are not many mocs that create something, I think this is why people are so eager to build it.

It's probably also the fact that the model is not too big and needs only a moderate number of pieces, all fairly common ones. Most of the MOCs that people make instructions for are very expensive to get all the pieces for.

[PG52]

Thank you all for the compliments, i'm glad you find it fantastic !

I saw too in my family and friends that they are much more interested when the MOC isn't the final goal, as spirographs or GBCs for example. When they can consider the LEGO bricks as a building material and not as the central point of the MOC.

And when it creates something, it's even better. Some people who didn't care of LEGO cars or trucks, or detachable gondola (sic) make round eyes when they see a spirograph running.

The BS folder isn't public yet, I'm curious to see what problems you found and how you solved them DrJB !

And now... The 5.2th one.

And the kind of drawing it makes :

And the video :

(I don't know if it will work...)

EDIT : it works :)

Edited November 3, 2013 by PG52

[legolijntje]

Nice work. As you said, it looks a bit less good as the previous one, but it has a lot more options. I can count 11 driving rings in total, am I right?

I hope I have some time in the next weeks to try to make an LDraw file (do you have more pictures or an lxf?) and build it myself to try it

[JM1971]

Have you put this on cuusoo?

I think you should :)

[PG52]

Thanks.

You're right, 11 driving rings, but the 6th will have at least 15...

I will make an lxf file when I find time, probably on the next WE :)

I haven't put it on Cuusoo, you really think I should ? Maybe with a better design... Maybe the 6th version :)

[JM1971]

If you can improve it more then I would also say wait until then.

[Lego Otaku]

It may be too complex for cuusoo? Multiple levers that changes how it draws, the building, and if my math is correct with your current 11 drive model, 121 possible combinations for many unique drawing is possible. What then when someone uses all possible combinations? Turn it into 2000-pieces spare part fodder?

Here's one possible idea: what if you separated the left and right arm from the main motor, used 2 motors connected to IR receiver and used a remote controller to get 7 different speeds + forward/reverse capability (on top of multiple drive rings for more speed options)? One IR receiver can handle 2 different motors on 2 channels so both could run independently of each other.

[DrJB]

The BS folder isn't public yet, I'm curious to see what problems you found and how you solved them DrJB !

I corrected my post. I did not mean to say it was a weak design, not at all ... but some (recent) gears have a smaller clamping force and thus a tendency to slip off their axle. Such is the case for the 12T gear on the 5.5 axle under the gearbox on the left. Also, the bracing I added is to make the design robust enough for kids to play with. All-in-all, a very good/clean design/layout.

Trying a math approach here: In the original version (one used to start this thread), there are 3 gearboxes with 4 positions each, and two direction controls for the left/right gears. For any given position of the pen, this MOC can create 4x4x4x2x2= 256 different shapes. To this, we may need to add combinations where none of the gears are engaged, or variation in the pen's position (how it is attached/tilted). Running all 256 possible drawings will for sure take some time ... though it would be fun entertaining kids at some day-long event. I'm thinking a possible mathematical model to draw such shapes ... Stay tuned.

Thinking a bit more about this ... all motions must be controlled by the SAME motor, otherwise the path never closes. This explains the intricacy of such beautiful designs.

Edited November 4, 2013 by DrJB

[legolijntje]

It may be too complex for cuusoo? Multiple levers that changes how it draws, the building, and if my math is correct with your current 11 drive model, 121 possible combinations for many unique drawing is possible. What then when someone uses all possible combinations? Turn it into 2000-pieces spare part fodder?

Here's one possible idea: what if you separated the left and right arm from the main motor, used 2 motors connected to IR receiver and used a remote controller to get 7 different speeds + forward/reverse capability (on top of multiple drive rings for more speed options)? One IR receiver can handle 2 different motors on 2 channels so both could run independently of each other.

No, please don't use receivers and remotes. The beauty of this model is its technical simplicity (but at the same time it's very complex). And, extra PF parts would make it cost more.