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History of the U.S.: The Not-so-microwave

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The same year that saw the invention of the atomic bomb also gave the world another hot device: the microwave oven. The principle behind microwave cooking was discovered by Percy Spencer, an engineer who worked for defense contractor Raytheon. After noticing a chocolate bar melted after accidentally being placed in front of a new “magnetron” vacuum tube, Spencer experimented with other foods, including popcorn (yes!) and an egg (not exactly). After these experiments, Spencer deduced that the food was being heated by low-density microwave energy that could penetrate solid objects. By October of 1946, Raytheon had filed a patent for a microwave based on Spencer’s idea.

The first oven intended for commercial sale in 1947 was almost six feet tall, tipped the scale at 750 pounds and cost $5,000 in 1947 dollars. The second version, produced in 1954, was better but still needed work: it gobbled electricity and cost $2,000– $3,000, at a time when the average cost of a new car was about $1,700. Figuring a home appliance manufacturer might have better luck than a defense contractor, Raytheon licensed the design to the Tappan Stove Company in 1952, but at $1,295, Tappan’s 1955 model still fell flatter than a microwave soufflé.

The food service industry was quicker on the uptake. Microwaves allowed the new generation of fast-food restaurants to thaw, cook, and sell large amounts of perishable food quickly, without violating health codes. Before long, manufacturers were employing microwaves to roast coffee beans, nuts, and potato chips. Factories even started using the ovens to treat non-food items like leather, tobacco, and cotton cloth. Regular households didn't care much about microwaves until 1967, when a relatively low-energy model costing just $500 came out.

Looking for more fabulous content like this? You’re in luck - The Mental Floss History of the United States hits bookshelves near you on October 5th! If you pre-order, you’ll get three free issues of mental_floss magazine. Get all of the details over here.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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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!

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Name the Author Based on the Character
May 23, 2017
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