Mindstorms Morse Key Writes to Drawbot

[Jason Allemann] built a Mindstorms Telegraph Machine that packs so many cool details that HaD is about to have a fit.

First off, It’s a drawbot able to write letters, a difficult feat given a lack of native stepper motors and the limited gear options for Mindstorms.  Trying to draw letters with servos typically makes for some ugly letters. And how does the drawbot know what to write? You code them in with Morse code. The second video after the break shows [Jason]’s setup. He has a Mindstorms touch sensor with a LEGO Morse key attached to it. He simply taps on the key and the EV3 Intelligent Brick interprets his dots and dashes and translates them into letters.

Next off, [Jason]’s printer is built using one EV3 set. It’s one thing to build a cool Mindstorms robot with whatever you have in your parts bin, but the gold standard is to make a project that can be built with only one EV3 set. That way, anyone with the set can build the project. Precious few really cool projects can be built with just one set–[David Gilday]’s MindCub3r Rubik’s cube solver comes to mind. Dude, this is another one.

Last off, [Jason] breaks down how to build it, providing full LDraw building steps and EV3 code on his site. Even better, he shows how to supersize the project by adding a second EV3 brick, which can connect to the drawbot’s EV3 brick via bluetooth and serve as a standalone CW key. He shows off this part in the second video.

Icing on the cake, [Jason] even built a Morse reference book, done appropriately in 100% LEGO.

Hackaday loves innovative LEGO projects, like this game-playing robot and this LEGO exoskeleton.

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We Dig This LEGO Excavator Conversion

[Frank] was lucky enough to score a bucket wheel excavator LEGO set as a birthday present, and we won’t lie – we’re jealous. However, out of the box, the kit is somewhat limited; there is only one motor to animate the entire machine and it can’t be fully remote controlled. But don’t worry — [Frank] set out to change that (Google Translation).

The first part of the build was to add motors to control the different functions of the excavator. One motor was added for each of the two tracks to allow the machine to drive forwards, backwards, and turn. Two more motors were added to raise and lower the digging buckets, and spin the tower. Finally, the original motor was left in place to turn the conveyor.

With that done, [Frank] then used a Raspberry Pi 3 to control all the hardware, being sure to house the new electronics in LEGO for an original look. The Raspberry Pi might be a lot of muscle to simply control a few motors, but it made it quick and easy for [Frank] to implement a Wiimote as a controller over Bluetooth. You can check out a couple demo videos in his most recent update.

It’s a great project, and we’d love to see the Raspberry Pi put to good use by allowing control over the Internet so we can dig in the sand over lunch breaks. We’ve seen some great LEGO hacks before, like this method of modifying cheap gear motors to work with LEGO parts.

Making Spirographs with LEGO and Math

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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EV3DEV Lego Linux Updated

The ev3dev Linux distribution got an update this month. The distribution targets the Lego EV3 which is a CPU Lego provides to drive their Mindstorm robots. The new release includes the most recent kernel and updates from Debian 8.8. It also contains tools needed for some Wi-Fi dongles and other updates.

If you haven’t seen ev3dev before, it is quite simply Linux that boots on the EV3 hardware using an SD card. You don’t have to reflash the computer and if you want to return to stock, just take out the SD card. You can also use ev3dev on a Raspberry Pi or BeagleBone, if you like. There’s a driver framework included for handling sensors, motors, and other items using the file system.

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Converting a Robotic Motor For Lego Blocks

The Internet has brought a lot of advantage to life, not the least of which is access to really cheap electronic parts. [KarelK166] was buying cheap geared motors for projects, but they didn’t easily work with Lego blocks. He found an easy way to adapt them and–lucky for us–decided to share.

The process is pretty simple. The gearbox has two screws and an elastic band holding it together. Once the gears are exposed, you can drill a hole in two of them with a 4.8mm drill bit. This might take a little practice since the gear needs to hold still, but you also don’t want to crush the plastic teeth. You also need to enlarge a hole in the casing, but that’s easier to clamp down in a vise.

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Chocolate Factory Simulation Makes Bars with LEGO

[Michael Brandl] got to visit the Milka chocolate factory in Bludenz, Austria and was inspired to build this simulation of the production process for the LEGO world 2017 event in Copenhagen.

The process begins with the empty mold riding on a double row of tank treads. Subsequent modules seem to fill the mold with LEGO ingredients, cool the bars, and remove them from the mold. The last two steps rock: [Michael] built a dispenser that drops a tiny cardboard box onto the line, sized to hold 3 LEGO bars. The box rolls to the end of the line and is picked up by a pneumatic gripper that picks up the box and places it on a pallet.

While more whimsical than the LEGO liquid handler we featured recently, there are a lot of interesting robotic techniques to be learned here. On the reverse angle video you can see more of what’s going on with the wiring of the various motors and sensors. There are six EV3 bricks scattered along the length of the assembly line. The bricks control 15 small motors, 2 large motors, 7 touch sensors, and 3 light sensors. [Michael] added some nice touches, like the combo of two color sensors, seen around 1:45 of the reverse angle video, possibly used to keep the factory operations synced.

Check out [Michael’s] Mindstorms sendup of [Anouk Wipprecht’s] drink bot dress. The LEGO version was built for Robotexotica. In addition, he has a lot of projects featured on his site.

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LEGO Train Explores a World of Sparkling Light

[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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