Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning

iStock // Ekaterina Minaeva
iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

Twitter Bug Accidentally Alerted Users When Someone Unfollowed Them

iStock/bigtunaonline
iStock/bigtunaonline

Social media networks may notify you every time your former high school classmate has a birthday, but there's one piece of information most sites choose not to share with users. When someone unfriends or unfollows you, platforms like Facebook and Instagram will save you the pain of knowing about it. This is normally the standard on Twitter, but thanks to a new bug, some Twitter users have received notifications when people unfollowed them, Vice reports.

For several days in June, many Twitter users reported receiving push notifications on their phones every time one their followers removed them from their feed. The notifications didn't clearly reference the awkward situation: The bug told users that someone had “followed them back” when they had actually hit the unfollow button. People eventually caught on to what was really happening.

The bug apparently didn't affect all users, so if you unfollowed someone on Twitter in the past week or so, there's a chance they didn't notice. Though if they really wanted to know, there are third-party apps that show Twitter users who unfollowed them.

According to Fast Company, Twitter has resolved the issue and users no longer risk getting their feelings hurt every time they check their notifications. So feel free to continuing curating the list of people you follow in privacy.

[h/t Vice]

This Amazingly Simple Google Docs Hack Is a Game-Changer

iStock/ardaguldogan
iStock/ardaguldogan

The seconds it takes to manually open a Google Doc, Sheet, or Slide on your computer are short compared to the time you spend working in them. But if you're already feeling stressed or tempted to procrastinate, the process of going to Google Drive, selecting New, and opening a blank document can be annoying enough to disrupt your workflow. For people looking to maximize as much of their time as possible, Google introduced a hack late last year that creates a new Doc, Sheet, or Slide in seconds.

According to TechCrunch, you can launch a blank Google Doc in less time than it takes to type out a full web address. If you're already signed into your Google account, simply go to your web browser, type in doc.new (no www. required) and hit Enter to go to your fresh, new document. For Google Slides, do the same for slide.new, and for Sheets, use sheet.new. It doesn't matter if you pluralize the name of the app: Typing doc.new or docs.new will bring you to the same place.

Google owns the .new web domain, which allowed it to create these convenient hacks for its users. If you're a frequent user of Google's applications, you can bookmark the addresses so they pop up in your browser suggestions with just a couple keystrokes.

The new document shortcut is pretty straightforward, but there are several more Google Docs features that make life more convenient for users in unexpected ways, including features for automatically transcribing audio and outlining documents.

[h/t TechCrunch]

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