A LEGO Orrery

June 9, 2024 by Al Williams 6 Comments

We aren’t sure how accurate you can get with LEGO, but a building block orrery looks cool, if nothing else. [Marian42] saw one done a few years ago and decided to build a version with a different mechanism. At first, the plan was to use some 3D printed fixtures, but the final product is made entirely from LEGO bricks. Very impressive. The video below shows that it has been complete for awhile, but the write-up that goes into great detail has only just arrived and it was worth the wait.

This is one of those things that seems simple if you don’t think too hard about it. However, when you sit down to actually do it, there are a number of challenges. For one thing, the Earth tilts at 23.5 degrees, and as the planet rotates, the tilt stays in the same direction, making it tricky to model mechanically.

The moon also has a 5.15 degree inclination, but since that’s hard to notice at this scale, the LEGO orrery exaggerates it. So, the Moon’s track has its own set of design problems. The whole thing has to rotate on a concentric shaft, which is also tricky to get right with kids’ building blocks.

Compared to the last orrery we saw, this one is huge. We’ve always been partial to ones that you have to look up to.

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The end result of the build, a supersized ultrasonic sensor, held in a person's hands

A Super-Size Functional Tribute To An Ultrasonic Sensor

June 1, 2024 by Arya Voronova 6 Comments

Sometimes, it’s time to shut down the oscilloscope, and break out the cardboard and paints. If you’re wondering what for, well, here’s a reminder of an Instructable from [CrazyScience], that brings us back to cardboard crafts days. They rebuild one of the most iconic components for an electronics tinkering beginner — an ultrasonic distance sensor, and what’s fun is, it stays fully functional after the rebuild!

This project is as straightforward as it gets, describing all the steps in great detail, and you can complete it with just a hot glue gun and soldering iron. With materials being simple cardboard, aluminum foil, popsicle sticks, some mesh, and a single ultrasonic sensor for harvesting the transmitter and receiver out of, this is the kind of project you could easily complete with your kids on a rainy day.

Now, the venerable ultrasonic sensor joins the gallery of classics given a size change treatment, like the 555 timer we’ve seen two different takes on, or perhaps that one Arduino Uno. Unlike these three, this project’s cardboard skeleton means it’s all that simpler to build your own, what’s with all the shipping boxes we accumulate.

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Etch-A-Sketch Camera Is Open Source

May 20, 2024 by Lewin Day 4 Comments

The Etch-a-Sketch was a great toy if you were somehow born with the talent to use it. For the rest of us, it was a frustrating red brick filled with weird grey sand. [Every Flavor of Robot] has taken the irritating knob-encrusted oblong and turned it into something we can all enjoy, however, by building an Etch-a -Sketch camera!

The build is simple. It uses an ESP32 microcontroller to run the show, equipped with a camera. The camera is used to take a photo of the subject, and the image is then sent to a desktop computer. The desktop runs the image through an AI pipeline that generates a simplified version of the image, and the necessary G-Code to draw it on the Etch-A-Sketch. The toy’s knobs are operated by a pair of brushless motors which have been geared down to provide more torque.

It’s a neat project, and more details are available on GitHub. We’ve seen some other great mechanized Etch-a-Sketch builds before, too.

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Most of a three-key macro pad featuring a 3D-printed, LEGO-compatible plate.

3D-Printed Macro Pad Plate Is LEGO-Compatible

April 30, 2024 by Kristina Panos 2 Comments

We love LEGO, we love keyboards, and when the two join forces, we’re usually looking at a versatile peripheral that’s practically indestructible. Such seems to be the case with [joshmarinacci]’s LEGO-compatible 3D-printed plate for a three-key macro pad. For a first foray into scratch-built keyboard construction, we think this is pretty great.

The idea here is threefold: the plate holds the switches in place, negates the need for a PCB, and makes it possible to build the case completely out of LEGO. In fact, [joshmarinacci]’s plan for the keycaps even includes LEGO — they are going to 3D print little adapters that fit the key switch’s stem on one side, and the underside of a 2×2 plate on the other.

Although [joshmarinacci]’s plan is to design a PCB for the next version, there is plenty to be said for combining the plate and the PCB by printing guides for the wires, which we’ve seen before. We’ve also seen LEGO used to create a keyboard stand that fits just right.

Via KBD

Bonkers Nerf Blaster Sprays Balls Everywhere

March 14, 2024 by Lewin Day 3 Comments

Nerf blasters are fun toys, to be sure. However, they’re limited by factors like price and safety and what Hasbro thinks parents will put up with. Few caregivers would ever countenance a build like this one from [ItllProbablyWork].

It’s a blaster designed to fire 48 darts in a second or so, or a truly ludicrous 288 Nerf balls. Like so many rapid fire blaster designs, it’s based on a pair of rotating wheels which fling darts out at rapid speed. The trick to the rapid fire ability is the delivery of ammunition. In this case, the blaster has a rotating drum of 12 barrels, which can each be loaded with 4 darts or 24 balls. As the drum rotates into position, a trigger mechanism unlatches a spring which forces the contents of the barrel out through the wheels and on to the target.

It’s mostly pretty good with darts, but with balls, it tends to send them flying everywhere, including jamming a bunch into the blaster’s internals. It is very funny to watch, though.

We’ve seen some other great blaster builds recently, too. Video after the break.

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A Kyria split keyboard and wrist rests on a stand made of LEGO.

LEGO Keyboard Stand Fits Just Right

March 12, 2024 by Kristina Panos 3 Comments

Split keyboards are great for many reasons, but mostly because you can place the halves as far apart as you want and really give your arms and shoulders the room they need. [Jason Cox] hit the nail on the head, though: add in a couple of palm rests, and you now have four things that will potentially shift and drift out of place on your desk or keyboard tray. It was such a problem that [Jason] hardly ever used his Kyria. That is, until he built a stand out of LEGO to hold everything.

[Jason] was using a pair of Manfrotto pocket tripods to tent the keyboard, and those held their position surprisingly well, even though he tweaked them here and there over time. Ultimately, [Jason] knew he wanted the answer to be something customizable. And what’s more customizable than LEGO?

About $60 worth of new white bricks and plates later, [Jason] got to work, spending an evening building the thing. He ended up using a few bricks to hold the keyboard in place on the plate, and it worked perfectly.

Of course, he didn’t get the whole contraption exactly how he wanted it the first time, but tweaking builds is half the fun, right? After a while, [Jason] figured out he could rebuild the part that connects the two keyboard halves to go around a plastic piece at the back of the keyboard tray, which holds the whole thing in place. The end result? Wonderful. The Kyria stays in place, and now [Jason] is using it way more than before.

You know LEGO is versatile, but did you know you can use it to build a hydroelectric dam?

Via reddit

Build Yourself A Little Mangonel, You Deserve One

March 1, 2024 by Lewin Day 17 Comments

If you’re of a certain age, you almost certainly learned about mangonels by playing Age of Empires II. Any intermediate player will tell you they are a powerful siege weapon that nevertheless cannot destroy trees (in game). However, why limit yourself to experiencing this capable siege engine in digital form? With the help of [Arry Koster’s] design, you can build a little mangonel of your very own!

A good-looking siege engine is, more often than not, a well-performing one.

The build is intended for a student or hobbyist audience, and is for a mangonel roughly the size of a shoebox. That’s big enough to have some fun, without being so large as to get you into trouble. The project also comes complete with a useful spreadsheet that lets you simulate the performance of a mangonel hurling a projectile so you can better understand the physics involved.

The mangonel is constructed out of wood, just as medieval examples were. The guide explains how to put the the design together, including the use of graphite to lubricate moving parts — a technique also used historically. Beyond building the siege weapon itself, there are also instructions on how to instrument it with an Arduino to measure its performance accurately.

The only thing this project is missing is a brilliant video of the titchy siege machine in action. We want to see it knocking down some appropriately-sized castles! If you happen to be building your own siege engines, miniature or otherwise, don’t hesitate to drop us a line. Do include some excellent footage of your antics, to boot!