3D-Printed Boat Feeds The Fishes

December 16, 2024 by Lewin Day No comments

In most natural environments, fish are able to feed themselves. However, if you wanted to help them out with some extra food, you could always build a 3D-printed boat to do the job for you, as [gokux] did.

The concept is simple enough—it’s a small radio-controlled boat that gets around the water with the aid of two paddle wheels. Driven together, the paddle wheels provide thrust, and driven in opposite directions, they provide steering. A SeeedStudio XIAO ESP32 is the brains of the operation. It listens into commands from the controller and runs the paddle drive motors with the aid of a DRV8833 motor driver module. The custom radio controller is it itself running on another ESP32, and [gokux] built it with a nice industrial style joystick which looks very satisfying to use. The two ESP32s use their onboard wireless hardware to communicate, which keeps things nicely integrated. The boat is able to putter around on the water’s surface, while using a servo-driven to deliver small doses of food when desired.

It’s a neat build, and shows just what you can whip up when you put your 3D printer to good use. If you’d like to build a bigger plastic watercraft, though, you can do that too. Video after the break.

Continue reading “3D-Printed Boat Feeds The Fishes” →

An Over-Engineered Basement Monitor

November 25, 2024 by Lewin Day 10 Comments

[Stephen] has a basement that depends on a sump pump. What that means is if the pump fails or the power goes out, the basement floods—which is rather undesirable. Not wanting to rely on a single point of failure, [Stephen] decided to build a monitor for the basement situation, which quickly spiralled to a greater degree of complexity than he initially expected.

The initial plan was just to have water level sensors reporting data over a modified CATS packet radio transmitter. On the other end, the plan was to capture the feed via a CATS receiver, pipe the data to the internet via FELINET, and then have the data displayed on a Grafana dashboard. Simple enough. From there, though, [Stephen] started musing on the possibilities. He thought about capturing humidity data to verify the dehumidifier was working. Plus, temperature would be handy to get early warning before any pipes were frozen in colder times. Achieving those aims would be easy enough with a BME280 sensor, though hacking it into the CATS rig was a little challenging.

The results are pretty neat, though. [Stephen] can now track all the vital signs of his basement remotely, with all the data displayed elegantly on a nice Grafana dashboard. If you’re looking to get started on a similar project, we’ve featured a great Grafana guide at a previous Supercon, just by the by. All in all, [Stephen’s] project may have a touch of the old overkill, but sometimes, the most rewarding projects are the ones you pour your heart and soul into!

Building A Hydrogen-Powered Foam Dart Cannon

November 1, 2024 by Lewin Day 18 Comments

Nerf blasters are fun and all, but they’re limited by the fact they have to be safe for children to play with. [Flasutie] faced no such restrictions when building his giant 40 mm foam dart launcher, and it’s all the better for it.

This thing is sizeable—maybe two to four times bigger than your typical Nerf blaster. But that’s no surprise, given the size of the foam ammunition it fires. [Flasutie] shows us the construction process on how the 3D-printed blaster is assembled, covering everything from the barrel and body assembly to the chunky magazine. Loading each round into the chamber is a manual process, vaguely akin to a bolt-action mechanism, but simplified.

It’s the method of firing that really caught our eye, though. Each round has a cartridge and a foam projectile. Inside the cartridge is a quantity of flammable HHO gas generated, presumably, from water via electrolysis. The blaster itself provides power to a spark gap in the cartridge that ignites the gas, propelling the projectile through the barrel and out of the blaster.

We’ve seen plenty of Nerf blasters and similar builds around these parts, including some with a truly impressive rate of fire. Video after the break.

Continue reading “Building A Hydrogen-Powered Foam Dart Cannon” →

Mining And Refining: Mine Dewatering

October 17, 2024 by Dan Maloney 9 Comments

From space, the most striking feature of our Pale Blue Dot is exactly what makes it blue: all that water. About three-quarters of the globe is covered with liquid water, and our atmosphere is a thick gaseous soup laden with water vapor. Almost everywhere you look there’s water, and even where there’s no obvious surface water, chances are good that more water than you could use in a lifetime lies just below your feet, and accessing it could be as easy as an afternoon’s work with a shovel.

And therein lies the rub for those who delve into the Earth’s depths for the minerals and other resources we need to function as a society — if you dig deep enough, water is going to become a problem. The Earth’s crust holds something like 44 million cubic kilometers of largely hidden water, and it doesn’t take much to release it from the geological structures holding it back and restricting its flow. One simple mineshaft chasing a coal seam or a shaft dug in the wrong place, and suddenly all the hard-won workings are nothing but flooded holes in the ground. Add to that the enormous open-pit mines dotting the surface of the planet that resemble nothing so much as empty lakes waiting to fill back up with water if given a chance, and the scale of the problem water presents to mining operations becomes clear.

Dewatering mines is a complex engineering problem, one that intersects and overlaps multiple fields of expertise. Geotechnical engineers work alongside mining engineers, hydrogeologists, and environmental engineers to devise cost-effective ways to control the flow of water into mines, redirect it when they can, and remove it when there’s no alternative.

Continue reading “Mining And Refining: Mine Dewatering” →

Hackaday Links: June 2, 2024

June 2, 2024 by Dan Maloney 6 Comments

So you say you missed the Great Solar Storm of 2024 along with its attendant aurora? We feel you on that; the light pollution here was too much for decent viewing, and it had been too long a day to make a drive into the deep dark of the countryside survivable. But fear not — the sunspot that raised all the ruckus back at the beginning of May has survived the trip across the far side of the sun and will reappear in early June, mostly intact and ready for business. At least sunspot AR3664 seems like it’s still a force to be reckoned with, having cooked off an X-class flare last Tuesday just as it was coming around from the other side of the Sun. Whether 3664 will be able to stir up another G5 geomagnetic storm remains to be seen, but since it fired off an X-12 flare while it was around the backside, you never know. Your best bet to stay informed in these trying times is the indispensable Dr. Tamitha Skov.

Continue reading “Hackaday Links: June 2, 2024” →

Sound And Water Make Weird Vibes In Microgravity

April 29, 2024 by Donald Papp 1 Comment

NASA astronaut [Don Pettit] shared a short video from an experiment he performed on the ISS back in 2012, demonstrating the effects of sound waves on water in space. Specifically, seeing what happens when a sphere of water surrounding an air bubble perched on a speaker cone is subjected to a variety of acoustic waves.

The result is visually striking patterns across different parts of the globe depending on what kind of sound waves were created. It’s a neat visual effect, and there’s more where that came from.

[Don] experimented with music as well as plain tones, and found that cello music had a particularly interesting effect on the setup. Little drops of water would break off from inside the sphere and start moving around the inside of the air bubble when cello music was played. You can see this in action as part of episode 160 from SmarterEveryDay (cued up to 7:51) which itself is about exploring the phenomenon of how water droplets can appear to act in an almost hydrophobic way.

This isn’t the first time water and sound collide in visually surprising ways. For example, check out the borderline optical illusion that comes from pouring water past a subwoofer emitting 24 Hz while the camera captures video at 24 frames per second.

Retrotechtacular: The Other Kind Of Fallout Show

April 16, 2024 by Dan Maloney 29 Comments

Thanks to the newly released Amazon Prime series, not to mention nearly 30 years as a wildly successful gaming franchise, Fallout is very much in the zeitgeist these days. But before all that, small-F fallout was on the minds of people living in countries on both sides of the Iron Curtain who would have to deal with the aftermath of a nuclear exchange.

“Uwaga! Pył promieniotwórczy“ (“Beware! Radioactive Dust”) is a 1965 Polish civil defense film from film studio Wytwórnia Filmów Oświatowych. While the Cold War turning hot was not likely to leave any corner of the planet unscathed, Poland was certainly destined to bear the early brunt of a nuclear exchange between the superpowers, and it was clear that the powers that be wanted to equip any surviving Polish people with the tools needed to deal with their sudden change in circumstances.

The film, narrated in Polish but with subtitles in English, seems mainly aimed at rural populations and is mercifully free of the details of both fallout formation and the potential effects of contact with radioactive dust, save for a couple of shots of what looks like a pretty mild case of cutaneous radiation syndrome.

Defense against fallout seems focused on not inhaling radioactive dust with either respirators or expedient facemasks, and keeping particles outside the house by wearing raincoats and boots, which can be easily cleaned with water. The fact that nowhere in the film is it mentioned that getting fallout on your clothes or in your lungs could be largely avoided by not going outside is telling; farmers really can’t keep things running from the basement.

A lot of time in this brief film is dedicated to preventing food and water from becoming contaminated, and cleaning it off if it does happen to get exposed. We thought the little tin enclosures over the wells were quite clever, as were the ways to transfer water from the well to the house without picking up any contamination. The pros and cons of different foods are covered too — basically, canned foods dobry, boxed foods zły. So, thumbs up for Cram, but you might want to skip the YumYum deviled eggs.

Dealing with the potential for a nuclear apocalypse is necessarily an unpleasant subject, and it’s easy to dismiss the advice of the filmmakers as quaint and outdated, or just an attempt to give the Polish people a sense of false hope. And that may well be, but then again, giving people solid, practical steps they can take will at least give them some agency, and that’s rarely a bad thing.

Continue reading “Retrotechtacular: The Other Kind Of Fallout Show” →