Making Spirographs With LEGO And Math

June 29, 2017 by John Baichtal 11 Comments

Master LEGO builder [Yoshihito Isogawa] has been on a roll lately, cranking out a number of robots that make drawings reminiscent of the classic Spirograph toy. For instance, he built an elegant drawbot out of LEGO elements, seen above. At first glance the monicker “spirograph” seems wrong, because where are the gears? However, [Yoshihito] has them stashed underneath the sheet of paper, with magnets controlling the pens.

His drawbot consists of a platform (cleverly, an inverted LEGO plate) upon which a sheet of paper is laid. One or two pen holders, each with a pair of magnets underneath, rest on the sheet of paper. Beneath the plate, two pairs of spinning magnets rotate around a double layer of 11×11 curved racks, which then play the role of the classic spirograph rings. An EV3-controlled motor powers the whole thing.

He also makes use of an obscure part–the 14-tooth bevel gear, last manufactured by LEGO in 2002 and even then it was mostly sold in part assortments intended for the education market. It’s so obscure LEGO doesn’t even provide the gear in their online building program LEGO Digital Designer, though (of course) the LDraw folks re-created it — it’s brick 4143 in the library, seen below.

Spirograph Gear Math

This gear becomes important in spirograph-style projects because tooth count is everything. There really aren’t that many spirograph designs that can be made with LEGO, because there are a limited number of gears and they mostly have the same tooth counts–the smaller ones sport 8, 12, or 16 teeth, medium-sized ones 20 or 24 teeth, and larger ones 36 or 40 — see a pattern? Such predictability may be great for a building set, but it doesn’t engender a lot of spirograph diversity.

When you compute the number of vertices in a spirograph shape, you take the least common multiple of the two gears (or sets of gears) and divide by the small gear. So a 60-tooth turntable turning a pair of 14-tooth gears has an LCM of 420, and you divide by 28 to get the number of vertices: 15. Remove one of those smaller gears and the vertices increase to 30. The challenge in creating new shapes with a LEGO spirograph lays in swapping in new gears, just like the original toy, and having more ways to come up with unusual gear ratios makes for more interesting drawings.

Another that makes the 14-tooth gear so alluring to [Yoshihito] is that it’s one of the few LEGO gears with a number of teeth not divisible by 4. Among other things this means the gear meshes with an identical gear at 90 degrees. Usually the gears have the same number for each quarter of the circumference and meshing becomes a matter of jogging one gear a scosh. This can be a problem because LEGO axles have a “plus” shaped profile, and you may not want everything on that axle tilted as well — having a 90-degree solution makes a lot of sense.

[Yoshihito] designs LEGO robots out of Isogawa Studio and has written several books on advanced LEGO techniques, published by No Starch. He specializes in small and elegant mechanisms — finding the perfect set of elements that work together effortlessly. You can see an example in the gear assembly to the right — a pair of the aforementioned 14-tooth bevel gears, turned into a normal gear with the help of that golden spacer, none other than a One Ring from LEGO’s Lord of the Rings product line. You can find videos of his projects on YouTube.

[Yoshihito] has released a number of variants of the spirographing drawbot. What’s next? Maybe a harmonograph?

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Teaching STEAM With Fidget Spinners

June 23, 2017 by Brian Benchoff 72 Comments

A huge focus of the maker revolution has been a focus on STEAM education, or rather an education in science, technology, engineering, art, and mathematics. We’ve seen innumerable kits and tools designed to introduce children to STEAM apps, ranging from electronic Lego blocks to robotics kits built around interlocking plastic bricks. These are just a passing fad, but finally, we have what looks like a winner: a STEAM education fidget spinner.

Fidget spinners have spun into our hearts like a shuriken over the last few months, and [MakerStorage]’s latest project taps into the popularity of fidget spinners to put an educational — wait for it — spin on the usual STEAM education toolkit. This is exactly what the maker revolution needs.

On board this educational fidget spinner are a few RGB LEDs and an Arduino-compatible microcontroller development board. A coin cell battery powers everything, and in an interesting advancement of fidget spinner science, [MakerStorage] seems to be using a flanged bearing with a PCB. We’re seeing the march of technology right before our eyes, people. Right now there are two versions of the educational fidget spinner, one with an Arduino Pro Micro soldered to the board, and another with an ATMega-derived custom circuit on the board along with a PCB USB connector.

Haven’t gotten enough fidget spinner news? OH BOY does Hackaday have you covered. Here’s the Internet of Fidget Spinners, a fidget spinner with an embedded WiFi microcontroller and a bunch of blinky LEDs. Those LEDs form a Persistence of Vision display. It’s amazing, astonishing, and it’s in fidget spinner format. Bored with your oscilloscope? Turn it into a fidget spinner tachometer. There’s literally nothing that can’t be applied to the world of fidget spinners.

Internet Of Hungry Hungry Things

June 15, 2017 by Brian Benchoff 14 Comments

The Hippopotamus is the most dangerous large animal in Africa. The Internet of Things will kill us all. What do you get when you combine the two? Hungry hungry. [Mike] took the classic game Hungry Hungry Hippos and turned it into an amazing and amusing Internet of Things device with voice recognition and machine vision.

Hungry Hungry Hippos is a child’s (board?) game designed to teach children the virtue of gluttony. The board is surrounded by four lever-actuated plastic hippopotami, and the object of the game is to mash a lever and collect marbles in the mouths of these piggish pachyderms. [Mike] automated this game with four servos connected to these levers, with each servo controlled by a W65C265SXB single board computer. Yes, this project has code written in 6502 assembly.

Taking this a step further, [Mike] is using a Playstation 3 camera connected to a netbook for image processing. When the camera detects a marble in front of a particular hippo, that hippo becomes hungry hungry. Autoplaying Hungry Hungry Hippos. What a fantastic time to be alive.

The Internet of things connectivity? [Mike] also made these hippos controllable via Amazon’s Alexa with the help of an Electric Imp. To activate the blue hippo, all [Mike] needs to say is, “Alexa, tell game that blue hippo needs to eat.” It’s an Internet of Things computer vision AI hippopotamus. We all knew technology was eating us alive, but we never thought technology was hungry hungry.

You can check out [Mike]’s demo videos below.

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And The Grandfather Of The Year Award Goes To…

June 1, 2017 by Dan Maloney 11 Comments

Hacker dads often have great plans for all the fun projects they’ll build for their kids. Reality often intrudes, though, creating opportunities for hacker grandfathers who might have more time and resources to tackle the truly epic kid hacks. Take, for instance, [rwreagan] and the quarter-scale model railroad he built for his granddaughter.

Taking inspiration from a 1965 issue of Popular Mechanics, grandpa hit this one out of the park. Attention to detail and craftsmanship are evident from the cowcatcher to the rear coupler of this 4-2-0 steam engine replica, and everywhere along the 275 feet of wooden track — that’s almost a quarter-mile at scale. The locomotive runs on composite wood and metal flanged wheels powered by pair of 350-watt motors and some 12-volt batteries; alas, no steam. The loco winds around [rwreagan]’s yard through a right-of-way cut into the woods and into a custom-built engine house that’ll make a great playhouse. And there are even Arduino-controlled crossbucks at the grade crossing he uses for his tractor on lawn mowing days.

The only question here is: will his granddaughter have as much fun using it as he had building it? We’ll guess yes because it looks like a blast all around. Other awesome dad builds we’ve covered include this backyard roller coaster and a rocketship treehouse.

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LEGO Train Explores A World Of Sparkling Light

May 17, 2017 by John Baichtal 14 Comments

[bananenbuurman] converted his studio apartment into a glorious four-minute LEGO train course equipped with lights, motorized effects, and creative displays.

The train car sports a 360-degree camera, giving us a minifigure’s view of the whole course: a series of themed “rooms”—one papered in what appear too be Euro notes, while others have laptops, power supplies, motherboards, and other pieces of old hardware. You’re reminded of the train’s small size when it passes by various LEGO-scale elements like minifigures, looming as if they were six feet tall.

There are lights everywhere, from the LED indicators from various pieces of equipment, to holiday lights and an an impressive collection of novelty lighting. It’s almost like a Katamari Damacy level in terms of detail—the gate made of floppy drives is killer.

You can see more of [bananenbuurman]’s projects at Banana Neighbor.

[Thanks, MarkoeZ!]

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Sorting Two Tonnes Of Lego

May 7, 2017 by Jenny List 28 Comments

Have you ever taken an interest in something, and then found it’s got a little out of hand as your acquisitions spiral into a tidal wave of bags and boxes? [Jacques Mattheij] found himself in just that position with Lego. His online purchases had run away with him, and he had a garage packed with “two metric tonnes” of the little coloured bricks.

Disposing of Lego is fairly straightforward, there is a lively second-hand market. But to maximise the return it is important to be in control of what you have, to avoid packaging up fake, discoloured, damaged, or dirty parts. This can become a huge job if you do it by hand, so he built a Lego sorting machine to do the job for him.

The machine starts with a hopper for the loose Lego, with a slow belt that tips individual parts down a chute to a faster belt derived from a running trainer. On that they run past a camera whose images are analysed through a neural net, and based on its identification the parts are directed into appropriate bins with carefully timed jets of compressed air.

The result is a surprisingly fast way to sort large amounts of bricks without human intervention. He’s posted some videos, one of which we’ve placed below the break, so you can see for yourselves.

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Electromechanical Lunar Lander

May 3, 2017 by Jenny List 24 Comments

One of the smash hits of the 1970s arcade was Atari’s Lunar Lander. A landing craft in orbit around a moon would descend slowly towards the surface, and through attitude and thrust controls the player had the aim of bringing it safely in to land. Many a quarter would have been poured into the slot by eager gamers wanting to demonstrate their suitability for astronaut service.

It was to this game that [Chris Fenton] turned when he was looking for inspiration for the 2016 NYCResistor Interactive show, and the result was a Lunar Lander game with a difference, one in which the gameplay was enacted through a physical lander and lunar surface. In this case the moon in question is a papier-mâché-covered inflatable ball, and the lander is a 3D-printed model on the end of a lead screw. Control is provided by an Arduino, with a rough facsimile of the original control panel and a set of microswitches on the model to detect a crash or a safe landing.

The result is a surprisingly playable game, as can be seen from the video below the break.

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