Surfboard Gets Jet Upgrades

Surfing is a fun and exciting sport but a lot of beginners can get discouraged with how little time is spent actually riding waves while learning. Not only are balance and wave selection critical skills that take time to learn, but a majority of time in the water is spent battling crashing waves to get out past the breakers. Many people have attempted to solve this problem through other means than willpower alone, and one of the latest attempts is [Andrew W] with a completely DIY surfboard with custom impeller jet drives.

The surfboard is hand-made by [Andrew W] himself using a few blocks of styrofoam glued together and then cut into a generic surfboard shape. After the rough shaping is done, he cuts out a huge hole in the back of the board for the jet drive. This drive is almost completely built by [Andrew] as well including the impeller pumps themselves which he designed and 3D printed. The pair of impellers are driven by some beefy motors and a robust speed controller that connects wirelessly to a handheld waterproof throttle to hold while surfing. Once everything was secured in the motor box the surfboard was given a final shaping and then glassed. The final touch was an emergency disconnect attached to a leash so that if he falls off the board it doesn’t speed away without him.

The build is impressive not only for [Andrew]’s shaping skills but for his dedication to a custom jet drive for the surfboard. He spent over a year refining the build and actually encourages people not to do this as he thinks it took too much time and effort, but we’re going to have to disagree with him there. Even if you want to try to build something a lot simpler, builds like these look like a lot of fun once they’re finished. The build seems flawless and while he only tested it in a lake we’re excited to see if it holds up surfing real waves in an ocean.

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Sam testing the motor on his ebike

E-MonoWheel

Generally, monowheels are that wacky, wildly futuristic transport that we lump in the same category as hoverbikes and jetpacks: strange, currently impractical, but very cool. Not content with waiting for the distant future, [Sam Barker] made his own electric monowheel. (Video, embedded below.)

The hardest part of any monowheel is that the outside rim needs to stand enormous abuse. It supports the weight of the vehicle and provides most of the structural integrity, but also is the means of propulsion. [Sam]’s first thought was to use a trampoline frame as it is a round and reasonably sturdy tube steel. He 3D printed the rollers that connected the subframe to the trampoline frame. Flat bar stock was used to make the angles inside the subframe and straight tube steel connected the inner frame into a trapezoid. The trampoline frame was welded together and on the first test spin, it broke apart from the stress. It simply wasn’t strong enough.

Not to be dissuaded, he found a company that bends steel into custom shapes. He stole the e-bike kit from another bike he had converted earlier, and the wheel was turning. Some handles and foot-pedal later, it was time for a proper test drive. Overall, the result is pretty impressive and the double-takes [Sam] gets while riding down streets in town are wonderful. If you’re looking to scratch the monowheel itch, check out this wooden monowheel.

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3D Printed Marble Music Machine Looking Good Already

Inspired by the enormous marble music machines from the staggeringly talented [Wintergatan] and the marble run builds by [Daniel de Bruin], [Ivan Miranda] has been busy again building a largely 3D printed contraption to test his ideas around building his own marble music machine from scratch. (Video, embedded below.)

Leveraging his recent experiences with resin printing and his own giant 3D printer, he had no difficulty in producing everything he needed from his workshop, even if the design work apparently took ages.

The build shows how early in development this project is, as there are clearly quite a few issues to be dealt with, but progress looks encouraging so far. To be clear, plans are to ‘go big’ and this little eight-channel testbed is just to explore this issues around ball guiding, transport and ball release onto the first audio test device, a Korg Nano Pad 2.

Some significant teething problems were identified, such as when [Ivan] designed the ball lifter, he intended the balls to load from the rear, but then needed to switch it to load from the front. No big deal, simply reverse the motor direction to load balls on the opposite side of the mechanism. Sadly, that also meant the directly coupled note drum was now also rotating the wrong way to release the balls. Oops. A quick hack later and [Ivan] was back in business. Various parts needed shimming up with plates, but with 3D printers on the bench, knocking those out took little time or effort. This just shows how darn useful 3D printers can be, allowing you to iterate in a short time and feed your hacks back into the final version.

[Ivan] is clearly going to have a lot of ‘fun’ with this one, as [Wintergatan] will surely testify, these big musical marble machine builds are quite some undertaking. We shall definitely be tuning in later on to see where this one goes!

While we’re on the subject of the [Wintergatan] marble machines, here’s a mini homage to the latest Marble Machine X, and if you’re in the need for a 3D printed marble clock, then try this one for starters.

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a money shot of the hidden arcade

Arcade Machine Pack And Play

There’s something about the large imposing wooden box of an arcade machine that lends a confident presence to a room. The problem with a tall and heavy box is that it takes up quite a bit of space and readily draws the eye. So [Alexandre Chappel] set out to avoid that and build an arcade machine that could hide in plain sight.

Extra points awarded for neat wiring on the inside.

The idea is a wooden box hung on the wall that folds up when not in use. [Alex] starts with Baltic birch plywood cut into the panels. Next, he applies edge banding (a thin veneer with some glue on the backside) so that all the exposed edges look like natural wood. Next, a screen hole is routed into the face frame, allowing an LCD monitor to sit snuggly in. A combination of pocket holes and biscuits allows [Alex] to assemble everything with no visible screws or fasteners.

With the help of a 3D printer, he quickly fabricated a locking mechanism to keep the front panel attached when it folds up. The hinge is also 3D printed. The typical Raspberry Pi 4 powers this particular machine. Two french cleats hold the box onto the wall, and once the system is on the wall, we have to say it looks incredible.

If you’re looking for a smaller but more traditional arcade cabinet, why not take a look at this arcade cabinet for toddlers? Or, if you loved the solid wood look of the hidden arcade, this full-sized solid oak cabinet would be something you would enjoy. Video after the break.

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Trying And (Mostly) Failing To 3D Print A Hydrofoil

[Sam Barker] had a boring dingy that he wanted to spice up a bit, so he resolved to 3D print a hydrofoil wing for it so that it could fly across the water. (Video, embedded below.)

With a large wing designed and sliced into several pieces, and a total print time of 200 hours, [Sam] was ready to glue the foil wing together when he realized his scale was way off and the wings were far too large for his boat. With some hacking, [Sam] was able to use a single wing across the bottom of the ship. [Tom Stanton] came over to help with fiberglassing, and they were ready for a test.

As you might have guessed from the title, the test wasn’t particularly successful. Swapping the engine on the boat for a more potent motor gave the lift he needed in the front, but without a back foil, it was a wheelie rather than what [Sam] hoped for. Back at home, they printed a second wing and went back for a second test. The boat would start to lift out the water, but the shaft of the engine lifted out of the water, sending him back down. Unfortunately, a downpour cut the test short.

Not to be defeated entirely, [Sam] connected it to a much larger boat once the weather cleared and pulled his dingy along behind. To [Sam’s] credit, they did get some solid foiling, and the ship did lift out of the water until the wings sheared off from the stress. All in all, an entertaining story of engineering while racing against the weather.

We admire [Sam’s] ambition, and if you’re thinking about building a whole hydrofoil, we suggest starting with a smaller RC model and scaling up from there.

3D Printed Absolute Encoder Is Absolutely Wonderful

When you need to record the angle of something rotating, whether it’s a knob or a joint in a robotic arm, absolute rotary encoders are almost always the way to go. They’re cheap, they’re readily available, and it turns out you can make a pretty fantastic one out of a magnetic sensor, a zip tie, and a skateboard bearing.

When [Scott Bezek] got his hands on a AS5600 magnet sensor breakout board, that’s just what he did. The sensor itself is an IC situated in the middle of the board, which in Scott’s design sits on a 3D-printed carrier. A bearing mount sits atop it, which holds — you guessed it — a bearing. Specifically a standard 608 skateboard bearing, which is snapped into the mount and held securely by a zip tie cinched around the mount’s tabs. The final part is a 3D-printed knob with a tiny magnet embedded within, perpendicular to the axis of rotation. The knob slides into the bearing and the AS5600 reads the orientation of the magnet.

Of course, if you just wanted a rotary knob you could have just purchased an encoder and been done with it, but this method has its advantages. Maybe you can’t fit a commercially-available encoder in your design. Maybe you need the super-smooth rotation provided by the bearing. Or maybe you’re actually building that robotic arm — custom magnetic encoders like this one are extremely common in actuator design, and while the more industrial versions (usually) have fewer zip ties, [Scott]’s design would fit right in.

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Prepare For Wildfire Season With An Air Quality Monitor

For some reason, wildfire seasons in Australia, North America, and other places around the world seem to happen more and more frequently and with greater and greater fervor. Living in these areas requires special precautions, even for those who live far away from the fires. If you’re not sure if the wildfires are impacting your area or not, one of the tools you can build on your own is an air quality meter like [Costas Vav] shows us in this latest build.

The air quality indicator is based around an Adafruit Feather RP2040 which is in turn based on the 32-bit Cortex M0+ dual core processor. This makes for a quite capable processor in a small package, and helps accomplish one of the design goals of a rapid startup time. Another design goal was to use off-the-shelf components so that anyone could easily build one for themselves, so while the Feather is easily obtained the PMS5003 PM2.5 air quality sensor needed to be as well. From there, all of the components are wrapped up in an easily-printed enclosure and given a small (and also readily-available) OLED screen.

[Costas Vav] has made all of the files needed to build one of these available, from the bill of materials to the software running on the Pi-compatible board to the case designs. It’s a valuable piece of technology to have around even if you don’t live in fire-prone areas. Not only can wildfire smoke travel across entire continents but simple household activities such as cooking (especially with natural gas or propane) can decimate indoor air quality. You can see that for yourself with an army of ESP32-based air quality sensors.