Lego Guitar Is Really An Ultrasonically-Controlled Synth

January 26, 2023 by Lewin Day 4 Comments

The phrase “Lego Guitar” can be a stressful one to hear. You might imagine the idea of strings under tension and a subsequently exploding cloud of plastic shrapnel. This build from the [Brick Experiment Channel] eschews all that, thankfully, and is instead a digital synth that only emulates a guitar in its rough form factor.

The heart of the build is a Lego Mindstorms EV3 controller. It’s acts as the “body” of the guitar, and is fitted with a Lego “fretboard” of sorts. A slide is moved up and down the fretboard by the player. The EV3 controller detects the position of the slide via an ultrasonic sensor, and uses this to determine the fret the user is trying to play. The button the user presses on the controller then determines which of five “strings” the user is playing, and the selected note is sounded out from the EV3’s internal speaker. It’s strictly a monophonic instrument, but three different sounds are available: a bass guitar, a rock guitar, and a solo guitar, with all the fidelity and timbre of a 90s Casio keyboard.

It’s a fun and silly instrument, and also kind of difficult to play. The slide mechanism doesn’t offer much feedback, nor are the EV3 buttons intended for dynamic musical performance. Regardless, the player belts out some basic tunes to demonstrate the concept. We doubt you’d ever be able to play Through The Fire and Flames on such a limited instrument, but [Brick Experiment Channel] used their editing skills to explore what that might sound like regardless.

We’ve seen some other great synth guitars before, too. Modern microcontrollers and electronics give makers all kinds of creative ways to build electronic instruments with unique and compelling interfaces. Some are more successful than others, but they’re all fun to explore. Video after the break.

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A Simple Air Suspension Demo With Lego Technic

January 25, 2023 by Lewin Day 18 Comments

The most common suspension systems on automobiles rely on simple metal springs. Leaf spring and coil spring designs both have their pros and cons, but fundamentally it’s all about flexing metal doing the work. Air suspension works altogether differently, employing gas as a spring, as demonstrated by this simple Lego build from [JBRIX].

The suspension system is employed on a Lego Technic car, with a relatively unsophisticated design. The car has no real form of propusion, and serves solely to demonstrate the air suspension design. They may look like dampers, but the system is actually using Lego pneumatic pistons as springs for each wheel. The pistons are connected to the upper control arm of a double wishbone suspension setup. Each piston is pneumatically connected to a main reservoir. With the reservoir, and thus the pistons, pressurized, the suspension system can support the weight of the car. If a bump perturbs a wheel, the piston compresses the air in the system, which then returns the piston to its original position, thus serving as a spring. If the reservoir is vented, the suspension collapses. Air springs on real, full-sized automobiles work in basically the same way. However, they usually have a separate reservoir per corner, keeping each wheel’s suspension independent.

Overall, if you’re working on some kind of Lego rambler, you might find this suspension concept useful. Alternatively, you might simply find it good as a learning aid. If you want to learn more about oddball suspension systems, we can help there too. Video after the break.

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3D Printing Giant LEGO-Like Blocks To Build Big Toys

January 18, 2023 by Lewin Day 21 Comments

[Ivan Miranda] is all about big 3D prints. He’s now set about printing giant blocks in the vein of LEGO Technic to build himself a full-sized rideable go kart. The project is still in progress, but [Ivan] has made great progress with his design.

The benefit of 3D printing giant blocks like this is that they open up the possibilities for rapid prototyping of big projects. It’s already easy to snap together a little LEGO tank, boat, or car at the small scale. Bigger blocks would make that possible for larger builds, too. Plus, once you’ve got plenty of blocks, there’s no need to wait for the 3D printer to churn out parts. You can just play with your toolbox of existing components.

[Ivan]’s design has faced some teething problems along the way. He struggled to solve various coupling problems for joining the blocks in various orientations, and made iterative changes to solve the issue. Eventually, he realized if he just eliminated an offset between the top and side holes of his beam design, everything would neatly work out. Plus, he learned that he could print a tiny scale version of his big blocks in order to test out designs without using as much plastic.

We love the idea of having a garage full of adult-sized LEGO-style blocks for big projects. The only caveat is that you really need a giant printer like [Ivan’s] to make them. Continue reading “3D Printing Giant LEGO-Like Blocks To Build Big Toys” →

A Christmas-themed LEGO train engine and coal car

ESPHome Powers Festive Lego Train Set

December 27, 2022 by Robin Kearey 5 Comments

While the basic concept of LEGO bricks might have changed little since the mid-20th century, some components such as motors and sensors are still affected by technological progress and end up obsolete and unsupported. [Travis] ran into this problem when he was building a festive train setup and realized he didn’t have the speed controller to match his train engine. Without that part, the engine would only run at full speed and derail as soon as it hit a curve. The official speed controller had been discontinued and was hard to find, so [Travis] had to resort to building his own.

The basic components needed were an H-bridge driver to operate the motor and an ESP8266 to generate PWM signals. In order to keep the bricky appearance of the train engine intact, [Travis] hollowed out a few cheap imitation LEGO bricks to house the electronics. He also cut out slots for JST connectors, which are far more convenient to work with than LEGO’s brick-style connectors.

The ESP8266 runs ESPHome, which enables [Travis] to control the entire setup using Home Assistant. The train is programmed to run a few laps at the top of the hour and play choo-choo sounds from a mini MP3 player hidden in the coal car. That car also holds a standard AA battery holder to power the system, which makes it easy to swap the batteries without having to partially disassemble the train.

There are various ways to control LEGO creations using standard computer platforms: we’ve seen the ESP32 powering a LEGO tank, for instance. If you need a bit more computing power, there’s even an official LEGO Raspberry Pi HAT.

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More Detail On That Fantastic Lego OLED Brick

December 20, 2022 by Dan Maloney 38 Comments

It’s always great when we get a chance to follow up on a previous project with more information, or further developments. So we’re happy that [“Ancient” James Brown] just dropped a new video showing the assembly of his Lego brick with a tiny OLED screen inside it. The readers are too, apparently — we got at least half a dozen tips on this one.

We’ve got to admit that this one’s a real treat, with a host of interesting skills on display. Our previous coverage on these bedazzled bricks was disappointingly thin on details, and now the original tweets even seem to have disappeared entirely. In case you didn’t catch the original post, [James] found a way to embed a microcontroller and a remarkably small OLED screen into a Lego-compatible brick — technically a “slope 45 2×2, #3039” — that does a great job of standing in for a tiny computer monitor.

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Gaze Upon The Swimming Mechanical Stingray, Made With LEGO

December 10, 2022 by Donald Papp 5 Comments

Stingrays have an elegant, undulating swimming motion that can be hypnotic. [Vimal Patel] re-created this harmony with his fantastic mechanical mechanical stingray using LEGO pieces and a LEGO Technics Power Functions motor. The motor is set in a clever arrangement that drives the motion remotely, so that it and electrical elements can stay dry.

The mechanical stingray sits at the end of a sort of rigid umbilical shaft. This shaft connects the moving parts to the electrical elements, which float safely on the surface. This leaves only the stingray itself with its complex linkages free to move in the water, while everything else stays above the waterline.

We’ve seen some impressive LEGO creations before, like this race car simulator and pneumatic engine, and the mechanical action in this stingray is no exception. Interested in making your own? The part list and build directions are available online, and you can see it in action in the video embedded below.

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Building A LEGO Pneumatic Engine

November 17, 2022 by Lewin Day 6 Comments

Pneumatic engines aren’t something we use every day, but they’re compelling things to see working in practice. [Nico71] built an eye-catching example out of LEGO Technic, and it’s remarkably fully-featured.

The build relies on a single pneumatic cylinder driving a flywheel. Flow to the cylinder is determined by camshaft-controlled valves. The valves themselves are custom-built, composed of hose loops that are kinked to shut off flow. In addition to the basic operating components, the engine also features a throttle valve which uses the same kinked-hose principle. The main control valves are installed in a housing that can be rotated relative to the engine’s frame to vary the timing of the valves relative to the flywheel’s rotation. A gear system allows fine adjustment of the timing. The throttle and timing controls are accessible on a tidy control panel complete with a idle-adjust mechanism.

Those wishing to build one themselves can rejoice, for [Nico71] provides instructions for a small fee. We’ve seen other air engines before, too, often of the 3D-printed variety.

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