Huge 3D-Printed LEGO Go Kart Makes You The Minifig

April 19, 2020 by Mike Szczys 7 Comments

The LEGO Technic line is definitely the hacker’s flavor of LEGO. It brings a treasure trove of engineering uses that make axles, gears, pulleys, and motors a thing. The only problem is that it’s the inanimate minifigures having all of the fun. But not if [Matt Denton] has something to say about it. He’s building a huge 3D-printed go-kart with pieces scaled up 8.43 times the size of their LEGO equivalents. That’s large enough for an adult to fit!

You may remember seeing [Matt’s] previous attempt at something like this about three years back, but that was only around half the size of this one. He printed a blue kart for his nephew, but it didn’t quite scale up enough even for a child to ride. This one is impressively large, but that raises some interesting fabrication issues

The long beams that make up the frame of the vehicle and the axle piece (the black rods with an X-shaped profile) used for the steering column are far too long to print in one go. So the axle was printed in two parts with a square channel down the center that hides a single run of square tubing. But the beams are much more interesting. Printed in two parts, there’s a dovetail-shaped connector piece that holds the top joint together, and a hidden bolt for the bottom. Glue is also used along the joint to bolster the holding power of the mechanical fasteners.

In general, the weight and friction on this scaled up version need many considerations. [Matt] explains where he’s made design decisions — like perpendicular axle connectors that have proper bearings — to include mostly-hidden metal parts and fasteners to ensure the plastic doesn’t fail. The thing looks awesome, but just wait until you see the assembly process. It’s sooooo satisfying to watch the modular parts snap into place. The project’s still in progress and before he’s done he plans to add an electric motor to make the kart go.

Even if you’re not scaling a model up to full size, giant is a guaranteed recipe for fun. Case in point, [Matt’s] enlarged LEGO fork lift is a delight.

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The Evolution Of A 3D Printed Off-Road R/C Car

April 9, 2020 by Tom Nardi 13 Comments

For about as long as hackers and makers have been using desktop 3D printers, there have been critics that say the plastic parts they produce aren’t good for much else than toys and decorative pieces. They claim that printed parts are far too fragile to be of any practical use, and are better suited as prototype placeholders until the real parts can be injection molded or milled. Sure. Try telling that to [Engineering Nonsense].

He recently wrote in (as did a few other people, incidentally) to share the latest version of his incredible 3D printed remote control car, and seeing it tearing around in the video after the break, “fragile” certainly isn’t a word we’d use to describe it. Though it didn’t get that way overnight. The Tarmo4 represents a year of development, and as the name suggests, is the fourth version of the design.

We know the purists out there will complain that the car isn’t entirely 3D printed, but honestly, it’s hard to imagine you could get much closer than this. Outside of the electronics, fasteners, tires, and shocks, the Tarmo4 is all plastic. That includes the gearbox and drive shafts. [Engineering Nonsense] even mentions in the video that he’s not happy with the tires he’s found on the market, and that they too will likely get replaced with printed versions in the future.

While the car is certainly an incredible technical achievement, what’s perhaps just as impressive is the community that’s developed around it in such a relatively short time. Towards the end of the video he shows off a number of custom builds based on previous iterations of the Tarmo. We’re sure that interest from the community has played a part in pushing the design forward, and it’s always good to see a one-off project become something bigger. Hopefully we’ll be seeing even more from this passionate community in the near future.

Just like the Open R/C Project, Tarmo proves that 3D printed parts are more than a novelty. If these diminutive powerhouses can run with printed gears and drive shafts, then you shouldn’t have anything to worry about when you run off the parts for your next project.

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Put An Open Source Demon In Your Pocket

April 6, 2020 by Tom Nardi 10 Comments

Back in 1996, the Tamagotchi was a triumph of hardware miniaturization. Nearly 25 years later, our expectations for commercially designed and manufactured gadgets are naturally quite a bit higher. But that doesn’t mean we can’t be impressed when somebody pulls off a similar feat in the DIY space.

The Xling by [dsl] follows the classic Tamagotchi concept. A little creature, apparently inspired by the demon from Netflix’s Disenchantment, lives in your pocket and needs occasional attention to remain healthy. The user pushes a few buttons to interact with the creature displayed on the display to do…whatever it is you do with a pet demon. Feed it souls and what have you.

But unlike the iconic 90s toy, both the hardware and software for the Xling are open source. The CERN-OHL-W licensed PCB was designed in KiCad and features an ATmega1284P microcontroller and SH1106G controller for the 128 x 64 OLED display.

Power is provided by an AP3401 DC-DC converter, MCP73831 charge controller, and a 400 mAh 3.7 V battery. Everything fits inside of a 3D printed case that looks like it could easily hang off of a keyring.

While the hardware is admirable enough, the software side of things is quite interesting as well. The Xling is running on a FreeRTOS kernel ported to the ATmega, but the GPLv3 licensed firmware sill needs some work. Right now only a few core functions are implemented, and [dsl] is hoping to get some ideas and feedback from the community so his dream of a fully open source demonic Tamagotchi can finally be realized.

Build enough of them, and you might even be able to implement another virtual pet Singularity. But to be safe, maybe you shouldn’t.

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ESP8266 And Sensors Make For A Brainy NERF Ball

April 3, 2020 by Tom Nardi 4 Comments

For his final project in UCLA’s Physics 4AL program, [Timothy Kanarsky] used a NodeMCU to smarten up a carefully dissected NERF football. With the addition to dual MPU6050 digital accelerometers and some math, the ball can calculate things like the distance traveled and angular velocity. With a 9 V alkaline battery and a voltage regulator board along for the ride it seems like a lot of weight to toss around; but of course nobody on the Hackaday payroll has thrown a ball in quite some time, so we’re probably not the best judge of such things.

Even if you’re not particularly interested in refining your throw, there’s a lot of fascinating science going on in this project; complete with fancy-looking equations to make you remember just how poorly you did back in math class.

As [Timothy] explains in the write-up, the math used to find velocity and distance traveled with just two accelerometers is not unlike the sort of dead-reckoning used in intercontinental ballistic missiles (ICBMs). Since we’ve already seen model rockets with their own silos, seems all the pieces are falling into place.

The NodeMCU polls the accelerometers every 5 milliseconds, and displays the data on web page complete with scrolling graphs of acceleration and angular velocity. When the button on the rear of the ball is pressed, the data is instead saved to basic Comma Separated Values (CSV) file that’s served up to clients with a minimal FTP server. We might not know much about sportsball, but we definitely like the idea of a file server we can throw at people.

Interestingly, this isn’t the first time we’ve seen an instrumented football. Back in 2011 it took some pretty elaborate hardware to pull this sort of thing off, and it’s fascinating to see how far the state-of-the-art has progressed.

Infinite Flying Glider

April 2, 2020 by Bryan Cockfield 5 Comments

If you’ve exhausted your list of electronics projects over the past several weeks of trying to stay at home, it might be time to take a break from all of that and do something off the wall. [PeterSripol] shows us one option by building a few walkalong gliders and trying to get them to fly forever.

Walkalong gliders work by following a small glider, resembling a paper airplane but made from foam, with a large piece of cardboard. The cardboard generates an updraft which allows the glider to remain flying for as long as there’s space for it. [PeterSripol] and his friends try many other techniques to get these tiny gliders, weighing in at around half a gram, to stay aloft for as long as possible, including lighting several dozen tea candles to generate updrafts, using box fans, and other methods.

If you really need some electricity in your projects, the construction of the foam gliders shows a brief build of a hot wire cutting tool using some nichrome wire attached to a piece of wood, and how to assemble the gliders so they are as lightweight as possible. It’s a fun project that’s sure to be at least several hours worth of distraction, or even more if you have a slightly larger foam glider and some spare RC parts.

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Using The Steam Controller With LEGO Motors

April 1, 2020 by Tom Nardi 1 Comment

While Valve’s Steam Controller was ultimately a commercial failure, there’s no denying it’s an interesting piece of hardware. With dual trackpads, a wealth of buttons, and Bluetooth capability, it could be the ideal way to control your next build. Thanks to a recent project by [geggo], now you’ve even got an example you can follow.

A custom PCB holding an ESP32 and DRV8833 dual H-bridge motor controller is used to interface with standard LEGO motors using their stock block-like connectors. That means the board is a drop-in upgrade for whatever motorized creation you’ve already built.

Since the ESP32 obviously has WiFi in addition to Bluetooth, that also means this little board could be used to control LEGO projects over the local network or even Internet with some changes to the firmware.

Interestingly, while Valve officially enabled Bluetooth on the Steam Controller back in 2018, it sounds like some undocumented poking and reverse engineering was necessary to get it working here. That’s great for those of us who like a good hack, but if you’re more interested in just getting things working, [geggo] has been good enough to release the source code to get you started.

If you’re not interested in Bluetooth but want to get your creation up and moving, we’ve recently covered how one hacker used the ESP8266 to bring his LEGO train to life by integrating it into his smart home.

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Motorized LEGO Train Gets Qi Charging In The Track

March 22, 2020 by Tom Nardi 6 Comments

This project started, as many do, with a simple idea. [Ben Hoad] just wanted to take a static LEGO Hogwarts Express train kit and make it motorized. It was compatible with standard LEGO track pieces, so all he should have to do was figure out how to shoehorn a motor in there and be done with it. Right?

Well, you already know how things like this go. It started with adding the motor, which ended up being relatively straightforward once [Ben] used some community LEGO CAD tools to figure out which kits had the specific parts he needed to redesign the train in such a way that he’d have enough space inside for the motor without ruining the way it looked. But then the feature creep kicked in, and he found himself falling down that familiar rabbit hole.

A 3D representation of the train’s internal components.

The first problem was how to reliably power the train. It turns out the rear car was more or less empty already, so that became home for two 18650 batteries ~~(the project details say “16850” but we believe that is merely a typo)~~. [Ben] didn’t want to have to take the thing apart every time it ran down, so he wondered if it would be possible to add wireless charging.

A Qi coil in the bottom of the train car and one in a specially designed section of track got the power flowing, but getting them lined up proved a bit finicky. So he added a Hall effect sensor to the car and a strong magnet to the track, so the train would know when the coils were lined up and automatically pump the brakes.

So now he had a motorized train that could recharge itself, but how should he turn it on and off? Well, with an ESP8266 along for the ride, he figured it would be easy to add WiFi control. With a bit of code and the Homebridge project, he was able to get the train to appear as a smart switch to Apple’s HomeKit. That allows him to start and stop the train from his smartphone, complete with a routine that returns the train to the charging station once it’s finished making the rounds. [Ben] says the next steps are to put some sanity checks in, such as shutting the motors down if the train hasn’t passed the charging station in a few minutes; a sure sign that it’s not actually moving.

All [Ben] needs to do now is implement automatic LEGO train decoupling before the plastic Hogwarts students come back from spring break.