Author: Bryan Cockfield

1773 Articles

One Sailing Pulley To Rule Them All

March 6, 2026 by 23 Comments

When thinking of humanity’s ability to harness wind energy, many people will conjure images of windmills from places like The Netherlands or Persia. But people have been using wind energy for far longer than that in the form of sailing ships. Using the wind for transportation goes back another four thousand years or so, but despite our vast experience navigating the seas with wind alone there is still some room for improvement. Many modern sailboats use a number of different pulleys to manage all of the rigging, but this new, open-source pulley can replace many of them.

The pulley, or “block” as they are sometimes called, is built with a polymer roller made out of a type of nylon, which has the benefit of being extremely durable and self-lubricating but is a bit expensive. Durability and lack of squeakiness is important in sailing applications, though. The body is made from CNC-machined aluminum and is composed of two parts, which pivot around the pulley’s axis to allow various ropes (or “lines”) to be inserted without freeing one end of the rope. In testing, this design outperformed some proprietary stainless steel pulleys of similar size.

Another perk of this design is that it can be set up to work in many different applications on a sailboat, whether that’s for hoisting a mainsail or pulling in a jib or any other task a pulley could be used for. It can also be stacked with others in many different configurations to build custom pulleys of almost any type, and can support up to 14 mm lines. For a sailor this could be extremely valuable, because as it stands each pulley on a ship tends to be used in only certain applications, and might also be proprietary from a specific company. This pulley is being released into the open-source world, allowing anyone to create them who wants one.

Thanks to [Keith] for the tip!

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Portable Tow Rope Batman Would Be Proud Of

March 6, 2026 by 16 Comments

Out of all of Batman’s massive array of tools which turn a relatively ordinary person into a superhero, perhaps his most utilitarian is his grappling gun — allowing him the ability to soar around his city like Spiderman or Superman. [John Boss] isn’t typically fighting crime, but he did develop his own grappling gun of sorts which gives him another superpower: the ability to easily scale snowy hills to quickly get back to the top.

The grappling gun takes inspiration from a commonly used tool called a power ascender, which is often used in industry applications where climbing is required. This one is held in the hand and uses a brushless motor with a belt-driven 3:1 reduction for increased torque. The pulley system, bearings, and motor are all housed in a 3D printed enclosure and are powered by rechargeable Milwaukee power tool batteries. During prototyping the rope intake and output feed locations had to be moved to increase the pulley’s grabbing ability, and with a working prototype he swapped a lot of the plastic 3D printed parts out for metal to increase the sturdiness of the device.

The grappling gun was originally designed for a smaller child to get hoisted up a hill on a sled, but when stress testing the device [John] found out that it actually has more than enough capability to haul even an adult up a hill on skis. As an added bonus, the outfeed for the rope can be put into a bag and used to automatically coil the rope up when he’s done at the hill. Although this is a great solution for a portable rope tow, for something more permanent and more powerful take a look at this backyard rope tow that was built from spare parts.

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Ebike Charges At Car Charging Stations

March 5, 2026 by 17 Comments

Electric vehicles are everywhere these days, and with them comes along a whole slew of charging infrastructure. The fastest of these are high-power machines that can deliver enough energy to charge a car in well under an hour, but there are plenty of slower chargers available that take much longer. These don’t tend to require any specialized equipment which makes them easier to install in homes and other places where there isn’t as much power available. In fact, these chargers generally amount to fancy extension cords, and [Matt Gray] realized he could use these to do other things like charge his electric bicycle.

To begin the build, [Matt] started with an electric car charging socket and designed a housing for it with CAD software. The housing also holds the actual battery charger for his VanMoof bicycle, connected internally directly to the car charging socket. These lower powered chargers don’t require any communication from the vehicle either, which simplifies the process considerably. They do still need to be turned on via a smartphone app so the energy can be metered and billed, but with all that out of the way [Matt] was able to take his test rig out to a lamppost charger and boil a kettle of water.

After the kettle experiment, he worked on miniaturizing his project so it fits more conveniently inside the 3D-printed enclosure on the rear rack of his bicycle. The only real inconvenience of this project, though, is that since these chargers are meant for passenger vehicles they’re a bit bulky for smaller vehicles like e-bikes. But this will greatly expand [Matt]’s ability to use his ebike for longer trips, and car charging infrastructure like this has started being used in all kinds of other novel ways as well.

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Fish Drives Tank

March 1, 2026 by 13 Comments

Fish are popular animals to keep as pets, and for good reason. They’re relatively low maintenance, relaxing to watch, and have a high aesthetic appeal. But for all their upsides, they aren’t quite as companionable as a dog or a cat. Although some fish can do limited walking or flying, these aren’t generally kept as pets and would still need considerable help navigating the terrestrial world. To that end, [Everything is Hacked] built a fish tank that allows his fish to move around on their own. We presume he’s heard the old joke about two fish in a tank. One says, “Do you know how to drive this thing?”

The first prototype of this “fish tank” is actually built on a tracked vehicle with differential steering, on which the fish tank would sit. But after building a basic, driveable machine, the realities of fish ownership set in. The fish with the smallest tank needs is a betta fish, but even that sort of fish needs much more space than would easily fit on a robotics platform. So [Everything is Hacked] set up a complete ecosystem for his new pet, making the passenger vehicle a secondary tank.

The new fish’s name is [Carrot], named after the carrots that [Everything is Hacked] used to test the computer vision system that would track the fish’s movements and use them to control the mobile fish tank. There was some configuration needed to ensure that when this feisty fish swam in circles, the tank didn’t spin around uncontrollably, but eventually he was able to get it working in an “arena” where [Carrot] could drive towards some favorite items he might like to interact with. Mostly, though, he drove his tank to investigate the other fish in the area.

The ultimate goal was for [Everything is Hacked] to take his fish on a walk, though, so he set about training [Carrot] to respond to visual cues and swim towards them. In theory, this would have allowed him to be followed by his fish tank, but a test at a local grocery did not go as smoothly as hoped. Still, it’s an interesting project that pushes the boundaries of pet ownership much like other fish-driving projects we’ve seen.

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Computer Terminal Replica Inspired By 70s Hardware

March 1, 2026 by 11 Comments

Not so long ago, most computer users didn’t own their own machines. Instead, they shared time on mainframes or servers, interacting with this new technology through remote terminals. While the rise of cloud computing and AI might feel like a modern, more dystopian echo of that era, some look back on those early days with genuine fondness. If you agree, check out this 70s-era terminal replica from [David Green].

The inspiration for this build was a Lear Siegler ADM-3A terminal seen at a local computer festival. These machines had no local computing resources and were only connected to their host computer via a serial connection. The new enclosure, modeled on this design, was 3D-printed and then assembled and finished for the classic 70s look. There are a few deviations from a 70s terminal, though: notably, a flat LCD panel and a Raspberry Pi 3, which, despite being a bit limited by today’s standards, still offers orders of magnitude more computing power than the average user in the 70s would have had access to.

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Taser Chess Teaches Valuable Lessons The Hard Way

February 25, 2026 by 20 Comments

Over the last few centuries, behavioral psychologists have documented all kinds of ways of modifying our actions and the actions of various animals. From the famous Skinner boxes to many modern video game mechanics, animals and humans alike can learn through the addition or subtraction of various rewards and punishments. And it doesn’t only impact simple actions either; [Everything is Hacked] took this idea to the extreme, using painful electric shocks to teach himself to avoid making blunders while playing chess.

This positive punishment system uses a medical device called transcutaneous electrical nerve stimulation (TENS) to deliver an electric shock to the skin. The electrical jolt is routed through a custom-built, conductive chess board where each square is isolated from the others and controlled by its own relay. The pieces are conductive as well, so if one is placed on a square where it shouldn’t go a relay will switch on to quickly provide the behavioral modification. The control logic is provided by a Raspberry Pi running the Stockfish chess engine, and it keeps track of the locations of the positions of all the pieces by using MX switches in the base of each square on the board.

This project took [Everything is Hacked] over a year to get into a working condition, including having to rebuild the entire project twice after mishaps with baggage handling at an airline. But he was able to demo the board to the Open Sauce tech festival and even took it to his local park to play chess with the local hustlers. Unfortunately, he reports that he spent more time reworking and rewiring his board over that year than he did improving his chess game, so unfortunately he still hasn’t been able to win any of his money back yet. Perhaps combining this project with a chess-playing robot would help.

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Elongating A BMX For Drag Racing

February 24, 2026 by 9 Comments

BMX bikes are a unique frame geometry, essentially forgoing all travel efficiency for maneuverability and sturdiness. For how much abuse these bikes are designed to take, these are all good tradeoffs. But it turns out that these bikes also have an exceptionally low center of gravity, which could make them useful for drag racing, provided they’re given a suitably large electric motor and a few minor frame modifications.

The project began as a fun weekend project for friends [Sam Barker] and [Tom Stanton]. They had a 20″ BMX wheel with a massive integrated hub motor that seemed to be begging to be put onto a BMX bike that they had on hand. After hooking up a 72V, 20Ah battery to it they were quickly zipping around the driveway, but the short wheelbase on the bike was bottlenecking its maximum performace because the bike would wheelie under high throttle. To solve that, they broke out the welder and extended frame, which kept the wheelies to a minimum and allowed them to take it out and drag race.

Another benefit to the extended frame is that the bike has room to store its battery now as well; before the frame extension it was strapped to the side of the frame under the rider in a non-ergonomic fashion. The duo also had to figure out a braking solution since the BMX didn’t come with its own brakes, but a loaner caliper from a penny farthing was found for some basic stopping abilities. We might assume this bike is not street legal on many public roads, but not every ebike operates in the same legal jurisdictions you might be the most familiar with.

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