[jacquesm]

Sorting large volumes of Lego ... call me crazy :) (several metric tons worth)

[mrgoldenbrown]

I was hoping it was Lego sorting! Every kid's dream machine. I got to talk with Nathan Sawaya at an event where he brought boxes of mixed Lego for us to play with. (including some of the giant Lego boulder from the Mythbusters episode) He said paying his assistants to sort bulk used Lego was more expensive than ordering new bricks en masse. (In the context of his sculpture projects at least)

[jacquesm]

> He said paying his assistants to sort bulk used Lego was more expensive than ordering new bricks en masse.

That's roughly the economics of it. There is a cottage industry where people will sort lego in bulk by hand, effectively it's probably better to flip burgers on a $/hr base.

[detaro]

I thought it was Lego at first, but 39000 shapes seemed a bit much. I thought there were only 8-10k shapes?

[jacquesm]

  mysql> select count(*) from parts;
  +----------+
  | count(*) |
  +----------+
  |    38516 |
  +----------+
  1 row in set (0.00 sec)

Though I'm sure there is some overlap it's definitely not 70%.

[detaro]

That's really shapes and not counting colors/prints multiple times? (Not that it really matters to the scope of the problem ;))

[jacquesm]

No, if you multiply by colors it gets much worse. 100's of thousands of possibilities...

Of course not all parts exist in all colors so that helps (a bit), but it is quite an interesting problem to work on. Every assumption you make will be challenged.

Prints and stickers are counted separately but that's not a really huge number and they should be correctly identified (so the surface decoration matters as well in the classification).

[Aissen]

Do you also plan to detect counterfeit pieces ?

[jacquesm]

That's a really hard problem. In many cases there are subtle hints (color, the writing on the studs).

Spectrography might give a hint here due to the different formulation of the plastics but some of the knock-offs are now so good it can be very hard to tell them from the real thing.

I'm not really sure if 'counterfeit' is the right term, the companies selling these are not making pieces labeled 'lego', and in fact the Lego brand started out by copying an English product.

https://en.wikipedia.org/wiki/Kiddicraft

Damaged pieces and discolored pieces are also of interest and a very hard category to detect.

[zaf]

Nice project idea. After you do that have a go at sorting out the Lego Mindstorms bits and pieces!

[jacquesm]

Already part of it. It's all lego pieces, not just the bricks, basically any part lego ever produced (hence the approximately 39k shapes).

The problem is anything but trivial but I'm making good headway, proof of concept took a few months and for the last year or so I've been slowly making progress with a more robust and capable version.

It's a superficially trivial idea, any toddler could do it but to have a machine that does this with any degree of reliability is fairly complex.

If anybody is ever going to try something like this I'd give you just one piece of advice: control your inputs.

Anything you have to deal with in software can eat up capacity very fast so by conditioning your inputs the software can get simpler in ways that really matter.

[hipjiveguy]

cool! So why are you doing this? to sell them? and where did you get metric tons of lego?

[jacquesm]

> So why are you doing this?

Excellent question :) Because I'm mad ;)

> and where did you get metric tons of lego?

Auctions.