LEGO Strain Wave Gear is Easy on the Eyes

We are continually amazed by the things people do with LEGO and Technics, especially those that require incredible engineering skill. There’s an entire community based around building Great Ball Contraptions, which are LEGO Rube Goldberg machines that move tiny basketballs and soccer balls from one place to another. Except for a few rules about the input and output, the GBC horizons are boundless.

Famed GBC creator [Akiyuki] recently built a GBC module that’s designed to show the movement of strain wave gear systems. These types of gear systems are used in industrial applications where precision is vital. Strain wave gears are capable of reducing gear ratios in a small footprint.

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Laser Cut LEGO in MDF

It’s hard not to be a fan of LEGO. The humble plastic bricks from Denmark enabled many a young engineer to bring their architectural and mechanical fantasies to life. But one limitation was that you were stuck using the bricks LEGO designed. Thankfully, [John Sokol] has come up with a way to laser cut his own LEGO-compatible bricks, and provided the tools so you can do the same.

After hacking an OpenSCAD script to generate just the top pins of the block, [John] exported an SVG into Inkscape so that he could scale the pins properly before exporting a final PNG for the lasercutter. Using RDWorks, [John] was able to find an engraving setting that worked well with dry-erase whiteboard MDF — an unusual material for a brick, but functional nonetheless. The key here is that the engraving setting takes away just enough material to create a raised pin on the part, without cutting all the way through the MDF or burning the surface.

Despite some damage when removing the work piece from the laser cutter, the part mates up well with the official LEGO brand parts. We’d be interested to see how the MDF cut parts hold up over time compared to real LEGO bricks made in ABS, which seem to last forever.

This isn’t the first make-your-own-LEGO hack we’ve seen – maybe you’d like to 3D print your own bricks on a printer made of LEGO?

Crypto Features: They’re Not For Girls

If you have worked in an office that contained a typewriter, the chances are you’ve been in the workplace for several decades. Such has been the inexorable advance of workplace computing. It’s a surprise then to discover that one of the desirable toys from many decades ago, the Barbie Typewriter, is still available. Are hipster parents buying toy versions of vintage office machinery for their children to use in an ironic fashion?

Gone though are the plastic versions of mechanical typewriters that would have been the property of a 1970s child. The modern Barbie typist has an electronic typewriter at her fingertips, with a daisy-wheel printer. We’re treated to a teardown of the recent models courtesy of Crypto Museum, who reveal a hidden feature, Barbie’s typewriter can encrypt and decrypt messages.

Now the fact that a child’s toy boasts a set of simple substitution cyphers is hardly the kind of thing that will set the pulses of Hackaday readers racing, after all simple letter frequency analysis is hardly new. But of course, the Crypto Museum angle is only part of this story.

This toy is made in a suitably eye-watering shade of pink, and sold by Mattel with Barbie branding. But it didn’t start life as a Barbie product, instead it’s licensed from the Slovenian manufacturer Mehano. The original toy makes no secret of the crypto functions, but though they persist in the software on the Barbie version they are mysteriously absent from the documentation. The achievements of American women are such that they have given us high-level languages and compilers, or their software has placed men on the Moon, yet it seems when they are young a brush with elementary cryptology is beyond them in the way that it isn’t for their Slovenian sisters. This is no way to nurture a future Grace Hopper or Margaret Hamilton, though sadly if your daughter is a Lisa Simpson this is just one of many dumbed-down products she’ll be offered.

If you see a Barbie electronic typewriter in a yard sale or similar, and you can pick it up for a few dollars, buy it. It’s got a simple daisywheel printer mechanism that looks eminently hackable. Just don’t buy it for your daughter without also printing out the Crypto Museum page for her as the missing manual.

When the Martian lander running her code has touched down safely, you’ll be glad you did.

Via Adafruit.

Power Wheels Rescued, Restored and Enhanced

It seems power wheels are like LEGO — they’re handed down from generation to generation.  [Nicolas] received his brand-new Peg-Perego Montana power wheels in 1997 as a Christmas present. After sitting in a barn for a decade, and even being involved in a flood, it was time to give it to his godchildren, though not without some restoration and added features. His webpages have a very good write-up, just shy of including schematics, but you’ll find an abbreviated version below.

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Alexa Brings Back Singing Fish, This Time It’s A Good Thing

Remember Big Mouth Billy Bass? That’s the singing fish with which you could torture family members by having it endlessly perform a rendition of either “Take Me to the River” or “Don’t Worry Be Happy”.

Now [Brian Kane], a teacher at the Rhode Island School of Design, has connected Amazon’s Alexa to the fish. Speak the “wake word”, “Alexa”, and the fish’s head turns to face you. Then ask it any question you’d normally ask Alexa and Alexa’s voice answers while the fish opens and closes its mouth in time to the words. Want to know the weather? Ask the fish, which you can see [Brian] do in the video below.

[Brian] hasn’t given details on how he’s done it but he’s likely made use of the Alexa Skills Kit, an SDK from Amazon that let’s you use the Alexa voice recognition and speech service with your own hardware (wetware, aquaware?), just as Amazon does with their home assistant, Echo .

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Turning Broken Toy Into Laser Target Practice

[Mathieu] wrote in with his laser target practice game. It’s not the most amazing hack in the history of hackery, but it’s an excellent example of the type of simple and fun things you can do with just a little bit of microcontrollering.

Flasergun8irst off, the gun is a broken toy gun that used to shoot something other than red collimated light beams. The Arduino knockoff inside reacts to a trigger pull and fires the laser for around 200 milliseconds. The gun also has a “gas gauge” that fills up with repeated shots and cools down over time. And therein lies the game — a simple race to ten, where each player only has a fixed number of shots over time.

The targets are simply a light sensor, scorekeeping LED display, and a buzzer that builds tension by beeping at you as the countdown timer ticks down. The bodies are made out of 3D-printed corners that connect some of [Mathieu]’s excess wooden goat-cheese lids.

All the code is up on GitHub so you can make your own with stuff that you’ve got lying around the house. The “gun” can be anything that you can embed a laser in that makes it aimable. Good clean fun!

When LEGO Flies

Building your own drone is a common enough pursuit among Hackaday readers. There are quite a few LEGO enthusiasts around, too. A company named Flybrix wants to marry those two pursuits and is offering a kit that allows you to build your drone out of LEGO bricks.

The company isn’t affiliated with LEGO. The kits look like they have some pretty common motors and control hardware. There are a few custom pieces, but the real key appears to be a LEGO compatible mount for the motors. You can see a video about the kit, below.

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