Empty Spools Make Useful Tools, Like Counters

What’s the deal with getting things done? There’s a Seinfeld anecdote that boils down to this: get a calendar, do a thing, and make a big X on each day that you do the thing. Pretty soon, you’ll thirst for chains of Xs, then you’ll want to black out the month. It’s solid advice.

[3D Printy] likes streaks as well, and made several resolutions at the beginning of 2022. As the first of 30 videos to be made throughout the year, they featured this giant 3D printed counting mechanism (video, embedded below) that uses empty filament spools, some 3D prints, and not much else. These are all Hatchbox spools, and it won’t work for every type, but the design should scale up and down to fit other flavors.

This isn’t [3D Printy]’s first counter rodeo — he’s made several more normal-sized ones and perfected a clever carryover mechanism in the process, which is of course open-source. So each spool represents a single digit, and there are printed parts in the core that make the count carry over to the next spool. Whereas the early counters used threaded rod, this giant version rides on 2.5 mm smooth rod, so the spools can slide apart easily. But how does everything stay together? A giant elastic band made of TPU filament, of course — because the answer is always in the room.

Check out the video after the break, and stay for the 900%-sped-up assembly at the end.

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Hackaday Prize 2022: Compact Solar Tracking System Doesn’t Break The Bank

If you need to squeeze every available watt out of a solar panel, you’ll probably want to look into a solar tracking system. Unfortunately, they are usually quite large, heavy, and expensive. As an alternative, [JP Gleyzes] has put together a DIY solar tracking system that aims to address these issues.

Starting with a 100 W flexible solar panel purchased during a Black Friday sale, [JP] first created a simple frame using 20 mm PVC tubing and a few 3D printed brackets. It mounts on a wooden base with a printed worm gear rotation mechanism, powered by a stepper motor. The tilt is a handled by a lead screw made from a threaded rod, connected between the wooden base and the top of the solar panel, and is also driven by a stepper motor.

For even more efficiency, [JP] also created an MPPT charge controller with companion app using an ESP32, modified 20 A buck converter, and current sensor module. The ESP32 also controls the stepper motors. The optimum angle for the solar panel determined using the date, time, and the system’s GPS position. [JP] had also created a simple Android app to calibrate the panels’ start position.

This project is a finalist in the Planet-Friendly Power challenge of the 2022 Hackaday Prize, and all the details to build your own are available on your project page. Looking at the size of the system, we suspect future iterations could be even smaller.

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R2Home Is Ready To Bring Back Your High Altitude Payload

With high-altitude ballooning, you are at the mercy of the winds, which can move your payload hundreds of kilometers and deposit it in some inaccessible spot. To solve this [Yohan Hadji] created R2Home, an autonomous parachute-based recovery system that can fly a payload to any specified landing site within its gliding range.

We first covered R2Home at the start of 2021, when he was still in the early experimental phases, but the project has matured massively since then. It just completed its longest and highest test flight. Descending autonomously from a release altitude of 3500 m, with an additional radiosonde payload, it landed within 5 m of the launch point.

R2Home electronics with it's insulated enclosure
R2Home electronics with its insulated enclosure

R2Home can fly using a variety of steerable canopies, even a DIY ram-air parachute, as demonstrated in an earlier version. [Yohan] is currently using a high-performance wing for RC paragliders.

A lot of effort went into developing a reliable parachute deployment system. The main canopy is packed carefully in a custom “Dbag”, which is attached to a drogue chute to stabilize the system during free-fall and deploy the main canopy at a preset altitude. This is done with a servo operated release mechanism, while steering is handled by a pair of modified winch servos intended for RC sailboats.

All the electronics are mounted on a stack of circular 3D printed brackets which fit in a tubular housing, bolted together with threaded rods. With the help of a design student [Yohan] also upgraded the simple tube housing to a lockable, foam-insulated design to help it handle temperatures at high altitudes.

The flight main flight computer is a Teensy 4.1  plugged into a custom PCB to connect all the navigation, communication, and flight systems. The custom Arduino-based autopilot takes inputs from a GPS receiver, and pilots the system to the desired drop zone, which it circles until touchdown.

The entire project is extremely well documented, and all the design files and code are open source and available on Github. Continue reading “R2Home Is Ready To Bring Back Your High Altitude Payload”

3D Printed Skate Trucks Do Surprisingly Okay

If you can buy something off the shelf, there’s a good chance that someone has tried to 3D print their own version. [Daniel Norée] did just that with skateboard trucks, whipping up a design of his own.

The main body of the trucks is 3D-printed, as is the hanger. A 195 mm M8 threaded rod is then used through the center of the trucks in order to provide an axle for fitting the wheels and bearings themselves. He 3D-printed the parts using a carbon-fiber reinforced nylon with the slicer set up to maximize strength. In testing, they rolled around the neighbourhood just fine.

[Mayer Makes] found the design online, and 3D printed some using his own transparent high-impact resin, making a cool set of clear-ish trucks. It’s a tough material, which we’ve featured on this site before.

Those trucks ended up in the hands of [Braille Skateboarding], who put them through their paces. The trucks are loose, but take a good beating around the park. Eventually one of the trucks succumbs after landing many kickfilps and ollies on the concrete.

Other great skate hacks include casting your own wheels in a 3D-printed mold. Video after the break.

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The 3D Printed Car Tire Rim Finally Hits The Road, Sorta

When you think of “car rim” you probably think stamped steel or machined alloy with a sturdy drum to withstand the arduous life of the road, not something 3D printed out of ABS. That would be crazy, right? Not to [Jón Schone] from Proper Printing, who’s recently released an update about his long-term quest to outfit his older sedan with extruded rims.

There were a few initial attempts that didn’t go as well as hoped. The main issue was layer separation as the air pressure would stretch the piece out, forming bubbles. He increased the thickness to the absolute maximum he could. A quick 3D scan of the brake caliper gave him a precise model to make sure he didn’t go too far. He also couldn’t make the rim any bigger to fit a bigger wheel to clear the caliper, as he was already maxing out his impressive 420 mm build volume from his modified Creality printer.

A helpful commenter had suggested using a threaded rod going all the way through the print as a sort of rebar. After initially discounting the idea as the thickness of the rim gets really thin to accommodate the caliper, [Jón] realized that he could bend the rods and attach the two halves that way. Armed with a paper diagram, he cut and bent the rods, inserting them into the new prints. It’s an impressive amount of filament, 2.7 kg of ABS just for one-half of the rim.

It didn’t explode while they inflated the tire and it didn’t explode while they did their best to abuse it in the small alley they had selected for testing. The car was technically no longer road legal, so we appreciate their caution in testing in other locations. In a triumphant but anti-climatic ending, the rim held up to all the abuse they threw at it.

We’ve been following this project for several months now, and are happy to see [Jón] finally bring this one across the finish line. It sounds like there’s still some testing to be done, but on the whole, we’d call the experiment a resounding success.

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Building A High-Capacity Linear Servo Actuator

Linear actuators are useful things, moving things in straight lines rather than annoying circles like so many motors. [Retsetman] recently built a linear servo actuator of his own design with accurate positional control.

The design relies on a carriage that moves along a threaded rod, perhaps the most rudimentary design of linear actuator. A large brushed DC motor is used to turn the threaded rod through a 3D-printed 9:1 herringbone geartrain, shifting the actuator back and forth. End stop switches are used to disengage the motor to avoid damage to the mechanism. Feedback is via a ten-turn potentiometer driven off the output geartrain to match the range of the actuator to the rotational range of the pot.

The final build has a stroke of approximately 100 mm, and can lift and hold a 15 kg weight with ease. In a pull test, the actuator failed at a load just shy of 100 kg. If you’re looking for something smaller, though, you can try building a linear actuator out of old DVD drive parts instead. Video after the break.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Cat Keyboard

Special thanks to [Maarten], who stumbled upon this old gem of a geekhack thread by [suka]. It’s essentially a show and tell of their DIY keyboard journey, complete with pictures. [suka]’s interest started with a yen for ergonomic keyboard layout alternatives. They soon found the geekhack forum and started lurking around, practicing layouts like Neo and AdNW, which [suka] still uses today.

A pair of num pads wired up to a Teensy becomes a keyboard.When it was time to stop lurking and start building something, [suka] got plenty of support from the community. They knew they wanted a split ortho with a trackpoint and plenty of thumb keys. [suka] started by building them from old Cherry keyboards, which are easier to come by in Germany.

The first build was a pair of num pads turned landscape and wired up to a Teensy, but [suka] wanted those sweet, clacky Cherry MX switches instead of MLs. So the second version used a pair of sawed-off num pads from old MX boards.

When the Truly Ergonomic came out, it got [suka] interested in one-piece splits. Plus, they were tired of carrying around a two-piece keyboard. So their next build was a sexy monoblock split with a laser-sintered case and keycaps. But that was ultimately too uncomfortable, so [suka] went back to split-splits.

Everyone takes a different path into and through this hobby, and they’re all likely to be interesting. Is yours documented somewhere? Let us know.

What Could Have Been: The Dygma Raise

I do some streaming here and there, mostly for the sense of focus I get out of being live on camera. I like to find out what my people in chat are clacking on, and one of them told me they have a staggered split called the Dygma Raise. I hadn’t heard of it before that day, but this keyboard has been around for a few years now.

This same person told me that Dygma might make an ortholinear version sometime soon, but apparently Dygma wanted it that way from the beginning. According to the timely video below sent to the tips line by [deʃhipu], Dygma’s original plan was a split ortho with few keys and presumably a layer system.

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