You Can Build A Lego Rubik’s Cube

Rubik’s cubes are a popular puzzle — one found exciting or infuriating depending on your personal bent. [PuzzLEGO] has designed a LEGO Rubik’s cube, with the latest revision improving on flimsy earlier designs.

The first step was to design a core that would allow the cube to rotate freely without being too loose. This involved a lot of trial and error until [PuzzLEGO] found just the right combination of parts to do the job. From there, it was a matter of introducing the edge pieces and corner pieces without jamming everything up.

It took some experimenting to get everything moving together smoothly, but the end result is pretty impressive. It’s certainly not a build you’d use for speedcubing; the fragility meant that it took 20 minutes to solve just one face. [PuzzLEGO] hopes to make further improvements to increase playability.

If you want to replicate the feat, you’ll need plenty of little Lego bits and pieces, but it’s definitely a replicable build.¬†Alternatively, consider using Lego to build a Rubik’s Solver, instead. Video after the break.

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New Part Day: Raspberry Pi LEGO HAT

The Raspberry Pi Foundation have been busy little bees for the last couple of years producing their own silicon, new boards and now in collaboration with the LEGO Education team a new HAT to connect to the LEGO SPIKE education platform. This new HAT board will work with every Raspberry Pi board with a 40-pin GPIO header.

Based on the RPI2040 microcontroller, it makes an interesting detour away from dumb slave boards, although it looks like the firmware is closed (for now) so you’ll have to make do with the pre-baked capabilities and talk to it with the supplied python library.

According to the documentation, the communication between the Pi and the RPI2040 nestled beneath the HAT PCB is plaintext-over-serial, freeing up the majority of the GPIO pins for other uses. The board uses a surface mount pass-through type header which allows pins from the Pi to protrude through the PCB, allowing stacking more HATs on top. Curiously they decided to mount the PCB with active parts facing down, giving a flat rear surface to park things on. We suspect that decision was made to improve access to the LPF2 connectors, especially if they were surface mount parts.

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Wild Lego-Bot Pronks About Your Patio

Legged robots span all sorts of shapes and sizes. From the paradigm-setting quadrupeds built from a pit-crew of grad students to the Kickstarter canines that are sure to entertain your junior hackers, the entry point is far and wide. Not one to simply watch from the sidelines, though, [Oracid] wanted to get in on the quadruped-building fun and take us all with him. The result is 5BQE2, a spry budget quadruped that can pronk around the patio at a proper 1 meter-per-second clip.

Without a tether, weight becomes a premium for getting such a creature to move around at a respectable rate. Part of what makes that possible is [Oracid’s] lightweight legs. Designing the legs around a five-bar linkage tucks the otherwise-heavy actuators out of the leg and into the body, resulting in a limb that’s capable of faster movement. What’s more, 5BQE2 is made from the LEGO plastic building bricks of our heydays. And with a full bill-of-materials, we’re just about ready to head over to our parents’ garage and dust off those parts for a second life.

For some action shots of 5BQE2, have a look at the video after the break. And since no set would be complete without the building instructions, stay tuned through the full video to walk through the assembly process step-by-step.

Here at Hackaday, we’re certainly no stranger to walking automatons, but not all robots use their legs for walking. For a trip down memory lane, have a look at [Carl Bugeja’s] buzzing Vibro-bots and UC Berkeley’s leaping Salto.

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Lego Submarine Gets Balloon Ballast System

Lego is a fun building block which vast numbers of the world’s children play with every day. However, the mechanical Technic line of Lego building blocks has long offered greater options to the budding engineer. [Brick Experiment Channel] is one such soul, working hard on their latest Lego submarine.

The sub is built inside of a glass food container, chosen for its removable plastic lid with a watertight seal. This keeps all the mechanics dry, as well as the custom electronics built to allow a 27MHz RC controller to send signals to the Lego electronics. This is key as higher frequency radios such as Bluetooth or WiFi can’t penetrate water nearly as well.

A magnetic coupling fitted to a Lego motor is used to drive the propeller in the water without the leaks common when trying to seal a rotating shaft. A second coupling on a Lego servo along with a creative steering arrangement allows the propeller to be turned to steer the craft.

The ballast system is simple. A balloon is filled by a Lego motor running an air pump, capable of 3.0 mL a second and capable of creating a maximum pressure of 2.0 bar. When the balloon is inflated, the buoyancy goes up and the sub rises. Run the motor the other way and the balloon is emptied by a clever clutch and valve arrangement, reducing buoyancy and causing the sub to sink.

The sub isn’t perfect. Maintaining a set depth underwater can be difficult with the rudimentary ballast system, perhaps as the balloon changes shape with varying water pressure. Sometimes, Lego axles slip out of their gears, too, and the radio only works for a few meters under water.

However, simply building a Lego sub of any sort is a remarkable feat. It’s interesting to see the variances in the design compared to earlier projects from [Brick Experiment Channel], too, as we’ve featured their earlier subs before. Video after the break.

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Working LEGO Space Computers Are A Chip Off The Old Block

We all have our favorite classic LEGO bricks, and wouldn’t be surprised if one or more of the various space computers showed up on pretty much everyone’s list. [dyoramic] loves them so much that they built two different working versions that do different things.

The first one is about six times the size of the original brick. Inside the 3D printed case is an ESP32 and a 1.5″ OLED display. [dyoramic] wired up the top six buttons as inputs and the rest are just for looks. The screen defaults to the classic white cross on green that just sits there looking legit. But start pushing buttons and you’ll find other modes — the cross becomes a radar screen in one, the computer spits out space facts in another, there’s a falling bricks game, and finally, a time and date screen.

The second LEGO space computer build is even bigger — both were designed around the size of their screens. It has a Raspi 4 and shows a dashboard with the weather, time, date, latest xkcd, and a few cryptocurrency prices. [dyoramic] has an even bigger version in the works that will use a 720 x 720 screen and a handful of brown key switches as inputs. We can’t wait to see that one! For now, check out the build and demo of the first two after the break.

What can’t you do with LEGO? It feels like we’ve seen it all, from cameras to microscopes to continuously variable transmissions. Wouldn’t you love to drive one of those around the block?

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LEGO Pole Climbers Are Great Study In What It Takes To Go Vertically Upwards

Climbing a pole with a robot might sound complicated and hard, but it doesn’t have to be. This video from [Brick Experiment Channel] demonstrates multiple methods of doing the job while keeping things simple from a mechanical perspective. (Video, embedded below.)

The first method uses a gravity locking design, where the weight of the battery pack is placed on a lever arm to increase the normal force on the wheels gripping the pole. Increasing the length of the lever arm, reducing the angle of the crawler, or adding grippier tyres can all be used to increase the grip with this design. The final design of this type is able to climb most of the way up an 8 meter flagpole without too much trouble.

The next version uses rubber bands to help add tension to grip the pole. This too works well and makes it to the top of the flagpole. The final build is a circulating design that looks truly wild in action, and winds its way to the top of the flagpole as well.

It’s great to see the experimental method of designing these Lego creations, as well as seeing how they do in the wild. [Brick Experiment Channel] has been featured here before, too.

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A Simple LEGO Automatic Transmission

The automatic transmission in your average automobile can be a complicated, hydraulic-y thing full of spooky fluids and many spinning parts. However, simpler designs for “automatic” gearboxes exist, like this Lego design from [FUNTastyX].

The build is based around a simple open differential but configured in a unique way. A motor drives what would typically be one of the output shafts as an input. The same motor is also geared what would normally be the main differential input shaft as well. In these conditions, this double-drive arrangement would sum the speed input and lead to a faster rotational speed at the other shaft, which becomes the output.

However, the trick in this build is that the drive going to what would be the usual differential input is done through a Lego slipper clutch. This part, as explained by [TechnicBricks], allows the outer teeth of the gear to slip relative to the shaft once torque demand is exceeded. What this functionally does is that when the output of the “automatic gearbox” is loaded down, the extra torque demand causes the clutch to slip. This then leads to only one input to the differential doing any work, changing the gear ratio automatically.

It’s likely not a particularly efficient gearbox, as there are significant losses through the very simple clutch, we suspect. However, it does technically work, and we’d love to see its performance rated directly against other simple Lego gearbox designs.

It’s a little confusing to explain in text, but the video from [FUNTastyX] does a great job at explaining the principle in just a few minutes. We’ve seen plenty of crazy Lego gearboxes over the years, and we doubt this will be the last. Video after the break.

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