Domino Ring Machine Tips Tiles In A Never-ending Wave

Like to see dominoes fall? [JK Brickworks] has got what you need, in the form of a never-ending ring of falling and resetting tiles. LEGO pieces are the star in this assembly, which uses a circular track and moving ramp to reset tiles after they have fallen. Timed just right, it’s like watching a kinetic sculpture harmoniously generating a soliton wave as tiles fall only to be endlessly reset in time to fall again.

A Mindstorms IR sensor monitors a tile’s state for timing.

It’s true that these chunky tiles aren’t actually dominoes — not only are they made from LEGO pieces and hinged to their bases, they have a small peg to assist with the reset mechanism. [JK Brickworks] acknowledges that this does stretch the definition of “dominos”, but if you’re willing to look past that, it’s sure fun to see the whole assembly in action.

The central hub in particular is a thing of beauty. For speed control, an IR sensor monitors a single domino’s up/down state and a LEGO Mindstorms EV3 with two large motors takes care of automation.

The video does a great job of showing the whole design process, especially the refinements and tweaks, that demonstrate the truly fun part of prototyping. [JK Brickworks] suggests turning on subtitles for some added details and technical commentary, but if you’re in a hurry skip directly to 4:55 to see it in action.

Want to see more automated domino action? This domino-laying robot sets them up for you to knock down at your leisure, and this entirely different robot lays out big (and we do mean BIG) domino art displays.

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An image of a Modulex brick (left) next to a LEGO brick right. Both are 4x2 studs, but the Modulex brick is much smaller at 20x10x5 mm vs the LEGO's 32x16x9.6 mm.

Modulex Is LEGO’s Long Lost Cousin

We love LEGO here at Hackaday, but did you know that LEGO spun off a parallel product line made for architectural models called Modulex?

[Peter Dibble] takes us on a deep dive through the history of Modulex, starting with Godtfred Kirk Christiansen needing a better way to model actual buildings after trying to design a house in LEGO. The LEGO brick’s 5:5:6 ratio proved challenging for modeling full-sized projects, so Modulex was conceived around a 1:1:1 ratio 5 mm cube. This change means Modulex is not compatible with LEGO System bricks.

As architectural styles morphed through the mid-20th Century, designs based around blocky shapes became passe, and Modulex pivoted to targeting factory and city planning customers. Products later branched out to include wall charts and Plancopy photocopy-able planners along with reconfigurable signage. Modulex (now ASI) still goes on as one of the biggest signage companies in the world, but discontinued the bricks in 2004. An attempt was made to revive Modulex bricks in 2015, but LEGO Group bought the company that had the rights to the bricks and has no intention of producing Modulex.

For more LEGO hacks, checkout this machine learning LEGO sorter or these giant LEGO-like pieces.

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Model Train Delivers Fresh Coffee

Model trains are good fun, though few of them serve any purpose beyond amusement or authentic railway simulation. [ProjectAir] decided to put his model train to practical use by having it deliver fresh espresso, and faced plenty of difficult challenges along the way.

It sounds simple, but the practicalities of the task proved difficult. After all, even a slight wobble is enough to tip a coffee cup off a small train. Automating everything from the railway itself to the kitchen coffee machine was no mean feat either. Plus, the aim was to deliver coffee from a downstairs kitchen up to an upstairs office. This meant finding a way to get the train to climb a steep staircase and to carry the coffee over a 20-meter journey without losing the caffeinated beverage in the process. That required the construction of a fancy train elevator to do the job — an impressive accomplishment on its own.

The final system is a joy to watch. Having a train roll into the upstairs workshop with a fresh brew certainly beats having to go all the way downstairs for a cup. Just don’t think about the fact that moving the coffee machine upstairs might have been a quicker solution.

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Dad Builds Frickin’ Tank For His Son

We gotta love hacker Dads and Moms for being so awesome. Sooner or later, their kids get to play with some amazing toy that every other kid on the block is jealous of. [Meanwhile in the Garage aka MWiG] is one of those super hacker Dads who built a frickin’ Tank for his son (video, embedded below.). But it’s so much fun driving that beast around that we suspect Dad is going to be piloting it a lot more than the kid. The tank features metal tracks, differential steering, a rotating turret, periscopes and a functional paintball gun with camera targeting.

Building a tank, even if it’s a mini replica, needs an engine with a decent amount of torque. [MWiG] first tried reviving an old ATV engine, but it did nothing more than sputter and die. It went to the scrap heap after donating its rear transmission and axle. [MWiG] managed to get an old Piaggio scooter with a 250cc / 22 hp engine. The scooter gave up its engine, electricals and the instrument cluster before being scrapped. Looking at the final build, and the amount of metal used, we are left wondering how the puny 22 hp engine manages to drive the tank. We guess it’s the right amount of gearing for the win.

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I’ve Been Printing On The Dragon Railroad…

We know many people who put much effort into building model train setups. But [Rambros] has an entire set 3D printed, and the files are open source, so you can print your own or modify it to suit you. When we first read “complete open source ecosystem,” we thought it might have been a bit of hyperbole, but it isn’t. The S-scale set includes two locomotives, a tanker, a box car, a hopper car, and a gondola car. There are different sections of track, customizable with Fusion 360. The “Dragon Railway” takes a few mechanical parts and electronics, of course. You can see one of several videos about the system below.

You can control the whole system using Bluetooth and a smartphone. The electronics are pretty simple, consisting of an ESP32 board, some motor drivers, N20 motors, and a few miscellaneous parts. We expect it would be compatible with other off-the-shelf S scale tracks and cars, but we don’t know that for sure.

Although you’ll need Fusion 360 to customize, there are plenty of ready-made STL files if you want to get started quickly. Some of the track items, like the crossing and turnout are not customizable, anyway. One particularly  impressive item is a printed auto-coupler; while a small item, getting that to work reliably with printed parts seems like it may be the most difficult part of the whole thing.

Maybe an OLED display would be the next thing? We’ve seen other printed trains, but this seems like a real labor of love.

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RC Car Gets F1-Style DRS Rear Wing

DRS, or the Drag Reduction System, has become a key part of Formula 1 in the past decade. [Engineering After Hours] decided to implement the same system on an RC car instead.

The DRS system was implemented in Formula 1 to increase passing in the series. By moving a flap in the rear wing of the race cars, drag could be reduced, allowing a car to attain a higher top speed on the straights. The racing series limited the activation of the DRS wing to only cars following closely behind another. This artificially enabled them to gain a speed boost over the car in front to aid passing.

[Engineering After Hours] wanted to see if a tiny wing on a small RC car could work the same way. It would fundamentally come down to whether moving a tiny wing element would appreciably change the car’s drag or not. Naturally, on such a small scale, attaining high speeds would be necessary to detect much difference. At lower speeds, the difference in drag would likely be too negligible to notice.

The RC-scale DRS system fundamentally does work. With DRS engaged, flattening out the rear wing elements noticably reduced downforce at the rear. With the DRS not engaged, though, the rear wing on the car was creating so much downforce that the car was squatting at the rear and occasionally flipping end over end. [Engineering After Hours] didn’t get any top speed measurements, but estimated that the wing could potentially increase top speed by up to 7 mph with the DRS enabled.

We’ve seen [Engineering After Hours] bring other fun motorsport tech to RC cars before, too, like this amazing fan car build.

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CUTTING CABLES CURES TANGLED CORD CHAOS

The Toniebox is a toy that plays stories and songs for kids to listen to. Audio content can be changed by placing different NFC enabled characters that magnetically attach to the top of the toy. It can play audio via its built-in speaker or through a wired headphone connected to the 3.5 mm stereo jack. Using the built in speaker could sometimes be quite an irritant, especially if the parents are in “work from home” mode. And wired headphones are not a robust alternative, specially if the kid likes to wander around or dance while listening to the toy. We guess the manufacturers didn’t get the memo that toddlers and cables don’t mix well together. Surprisingly, the toy does not support Bluetooth output, so [g3gg0] hacked his kids Toniebox to add Bluetooth audio output.

[g3gg0] first played with the idea of transmitting audio via an ESP32 connected to the I²S interface, running a readily available A2DP library. While elegant, it is a slightly complex and time consuming solution. Using the ESP32 would also have affected the battery life, given the ESP32’s power hungry nature. Continue reading “CUTTING CABLES CURES TANGLED CORD CHAOS”