Peter Nolan Posted January 8, 2017 Posted January 8, 2017 Hello! I'm a first time poster in the Technic forum, but thought that my inverted spirograph might be of interest. Rather than move the pen, I used a planetary gear setup to move the paper. Different gear combinations give different results, as does the pen position. The pen-holding frame is made up from a lot of 2 x 4 bricks, but the guts of the machine is a hard plastic wheel with internal gear teeth (I'm not sure of the correct name, but this is the part I used: http://www.bricklink.com/v2/catalog/catalogitem.page?id=83393&idColor=11#T=C&C=11). Sadly the spirograph has now been dismantled--my son needed the parts for a Chima vehicle... Enjoy! Quote
captainmib Posted January 8, 2017 Posted January 8, 2017 That is really cool. Love the idea. I think you need to brace the pen better, or apply some down pressure. It would make the drawing a bit better. Quote
Peter Nolan Posted January 8, 2017 Author Posted January 8, 2017 Thanks for the feedback--yes, the linework was quite wobbly! The pens were Lego brand (with a cross-section almost the same as a 2x1 brick) but unfortunately they were a little undersized, which resulted in some play in the pen holder. If I was building it again I'd probably include some kind of locking mechanism to hold the pen. Cheers, Peter Quote
Diamabolo Posted January 1, 2021 Posted January 1, 2021 Great Work, to use a planetary gear to spin the paper. Do you have any detail pictures? Her is my planetery spirograph Quote
iLego Posted January 2, 2021 Posted January 2, 2021 4 hours ago, Diamabolo said: Her is my planetery spirograph This one is really nice ! One additional level of gearing is adding a lot to the final images. They look awesome. Quote
Peter Nolan Posted January 14, 2021 Author Posted January 14, 2021 Hi Everyone, seeing these comments got me thinking about what the different gear ratios would do. I've put together a table of all the possible gear combinations and the resultant number of points in a spirograph pattern. I've treated the 14 tooth gear combinations separately, since these can only mesh with double bevel gears (as far as I know). The maximum number of points is 18, when you rotate a 36 tooth gear around a fixed 14 tooth gear. Apologies for low quality image--I had to resort to a low-res jpeg to get the filesize small enough. Quote
Peter Nolan Posted January 29, 2021 Author Posted January 29, 2021 (edited) Just worked out some more gear combos--haven't figured out how to post html though... Also haven't figured out how to delete comments--please ignore this one. Edited January 29, 2021 by Peter Nolan Tried to test code formatting, didn't work and couldn't delete comment. Quote
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