Author: Zoe Skyforest

3683 Articles

Touchable POV Display Blooms In Mid Air

May 23, 2026 by 14 Comments

Typically, when we think of touch screens, we think of LCDs or OLEDs with a resistive or capacitive sensing layer laid over the top. However, a team from the University of Chicago has developed an entirely different type of touch-sensitive display that uses persistence-of-vision techniques.

The project is called BloomBeacon. It consists of a pair of spinning arms to create a stable round display in mid-air. One arm is covered in LEDs, while the other is covered with capacitive pads for touch sensing purposes.  The trick behind this device is evident in the name—the device uses soft, flexible arms which are hinged and “bloom” upwards as the device spins up to speed. This makes it safe to physically interact with the spinning blades while they’re in motion to create a touch-interactive display. The device can thus display user interface elements like buttons that the viewer can interact with by reaching out and touching them directly.

Normally we’d advise not sticking your fingers in a rotating piece of machinery, but in this case, BloomBeacon was designed specifically to make this safe. Even sticking your fingers or hand right through the spinning arms won’t cause injury.

We’ve featured some other cool POV projects over the years, like this neat volumetric display. Video after the break.

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Building An Analog Meter Watch

May 23, 2026 by 18 Comments

Most conventional analog watches have two or three hands, covering hours, minutes, and seconds (where present). [Sahko] has built a different kind of analog watch that creatively displays the time with just one. 

The build is based around a simple analog coil meter, which, at its heart, just sweeps its needle across a scale based on the voltage input to the device. A Raspberry Pi Pico is employed to drive the meter through a digital-to-analog converter. Pressing the buttons on the outside of the device tells the watch to display hours, minutes/seconds, or the current month or day of the week. With a single needle, only one parameter can be displayed at a time, but that’s just a compromise you accept for having a cool unique analog dial watch.

Another cool touch in the design is that the dial backer isn’t just a printed piece of paper—it’s a custom PCB, which has a much nicer, hardier finish. The case of the watch is also CNC milled out of aluminum and bead blasted for a quality surface finish, adding a nice industrial touch to the build.

This is a great example of a custom watch with quality fit and finish. The attention to detail really pays off in terms of feel. We’ve seen other watch projects use similar construction techniques before, too.

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Water-cooling A 3D Printed Rocket Isn’t Quite Practical

May 23, 2026 by 23 Comments

Consumer-grade 3D printers are useful for lots of things, but they kind of fall down when it comes to making stuff that survives high temperatures. [Mr. More Gooder] wasn’t deterred from a rocket build using FDM printed parts though, instead relying on water cooling to try and beat this practical limit.

The concept is simple enough—[Mr. More Gooder] printed a propane-burning combustion chamber and nozzle out of plastic that you’d totally expect to melt when the flames started. Thus, the nozzle was given fittings to allow water to be continually pumped through to try and drag away enough heat to let the rocket survive more than a few seconds. Unfortunately, during testing the uncooled combustion chamber quickly melted. A redesign with water cooling throughout performed a little better, until the water jacket began to leak into the main chamber and extinguished the flames. Melted plastic could be seen dripping out of the nozzle shortly after ignition, too.

Even if the nozzle did hold up for a longer period of time, it’s worth noting this is probably not a viable route towards a flight-ready engine. Mostly because you would need a huge supply of water to keep the components cool which would add a great deal of weight to any such build. There’s a reason NASA doesn’t recycle old drink bottles to make rocket engines, after all.

In any case, we love to see all sorts of rocket experiments, even the unsuccessful ones.

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The Team Behind The Flipper One Needs Your Help

May 22, 2026 by 33 Comments

You’ve probably heard of the Flipper Zero, a pocket-sized device that packs in lots of great hacking potential. The team behind it has now turned their efforts towards developing the Flipper One, and they’re calling out for help from the broader community. 

The Flipper One is not intended to be a replacement or sequel for the Flipper Zero. Instead, it’s designed to exist as a entirely new device in its own segment. The team is hoping to build “the most open and best-documented ARM computer in the world,” as they attempt to create a Linux cyberdeck of grand capability. Where the Flipper Zero has found great use for interrogating and investigating low level communications, like IR and NFC, the Flipper One is intended to go to a higher level, working with protocols like Wi-Fi, 5G, and Ethernet in the networked world.

The new device will be based around a co-processor architecture, where a microcontroller is paired with a capable CPU for great flexibility. It will also feature all the high-speed interfaces you’d expect, like PCI Express, USB 3.0, SATA, and Gigabit Ethernet. It’s a proper, capital-C Computer in that regard. The intention of the team is also to redefine some of the typical Linux experience, by creating GUI wrappers around certain traditional CLI utilities. It should go a long way to giving the software the same cyberdeck feel that the current prototypes embody in their hardware design.

If you want to learn more and get involved, head over to the Flipper One Development Portal and dive in. Alternatively, you might like to get up to speed with some of our prior reporting on the Flipper Zero. Happy hacking!

[Thanks to Andrew for the tip!]

The Maths Behind A Chord Recognition Engine

May 22, 2026 by 13 Comments

A key part of any tertiary musical education is learning about all the wonderful (and less wonderful) types of chords out there. Typically this involves a great deal of exercises involving the identification of a given chord from its component notes. But how would you do this programmatically? Well, thankfully, the developers behind the WhatChord tool are happy to explain just how it’s done.

The problem with classifying chords is that the way musicians use them and construct them can be quite varied. Names can also be applied somewhat differently depending on the musical context of a given set of notes. To suit the musical reality of real players and composers, WhatChord uses a specially-developed scoring algorithm to try and nut out what a chord is actually supposed to be.

As an example, a major chord must require a root note and a major third interval. It can optionally include a perfect fifth. However, if there is a minor third, minor seventh, or major seventh present, then you’re almost certainly not looking at a simple major chord. WhatChord takes these things into account by weighting the different tones present and seeing which chord gets the highest score. The required notes add weight, while notes that shouldn’t be there add a penalty to the score. Then there are extra penalties for ambiguous “unexplained” tones, extensions, and a few other parameters to disambiguate edge cases.

If you’d like to see how it works in practice, you can check out the WhatChord app and see how good it is for yourself. Alternatively, explore some of the other chord-focused projects we’ve featured over the years, or send your best musical projects into the tipsline.

[Thanks to baschwar for the tip!]

Injection Molding Your Own Rubik’s Cubes Takes Work

May 22, 2026 by 7 Comments

If you just want to play with a Rubik’s Cube, you can simply buy one from a local toy store. If you want to build one, you could 3D print something and put it together yourself. But what if you want to make lots of Rubik’s Cubes? Then, you might go down the road that [EngBroken] just walked.

What started as a fun reverse-engineering project would lead to an 8-month journey to reproduce Rubik’s Cubes from scratch using injection molding. [EngBroken] started by identifying the basic pieces that make up the cheap cube they bought, including the center core, the edge pieces, and the corner pieces. Parts were then recreated in CAD, and [EngBroken] then set about designing and milling injection molds out of 6061 aluminium to make the parts.

Amusingly, to get the correct colors for the separate parts of the cube, [EngBroken] made the curious decision to mix cut-up pieces of 3D printer filament with clear ABS pellets to tint it as needed. Parts were then assembled with UV-curing glue, and [EngBroken] had a Rubik’s cube built from scratch. Well he actually had several, since he had a stack of parts since injection molding is great at producing things in quantity.

This isn’t a great way to go if you want a Rubik’s cube on the cheap. [EngBroken] estimates the labor put in to this exercise came out to $56,000 alone, to say nothing of what it took to produce all those aluminium molds and source all that plastic. Still, a great deal was learned in the process. We’ve looked at the challenges of injection molding before, too.

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Autonomous Submarine Relies On Color Detection

May 22, 2026 by 5 Comments

We talk about all kinds of autonomous vehicles here at Hackaday, from aerial drones to rugged rovers. A little less common are the submarine builds, likely due to their technical complexity. That said, though they perhaps benefit most from autonomy given they’re so hard to talk to while underwater. In any case, [Ayman] has built an impressive sub that uses some rudimentary techniques to navigate around while under the surface. 

The build uses typical construction techniques for DIY subs of this size, with a clear acrylic tube serving as the body of the craft. It’s carefully sealed to ensure water ingress doesn’t send it to the bottom, using nifty tricks like a magnetic coupling for the prop. Inside, there’s a Raspberry Pi 4, kitted out with an Arducam IMX708 camera with a wide angle lens. It’s joined by a BNO085 inertial measurement unit, along with two BMP280 pressure sensors for keeping track of motion and the sub’s vital signs, while a DRV8833 motor controller runs the main drive motor.

There’s also an ESP32 which helps out with motor and servo control for steering, and ballast control. Sinking and floating the sub is handled with a pair of two ballast tanks constructed out of 5 mL syringes that are driven in and out with high-torque output gear motors. The build uses an antenna buoy so that communication can be maintained with the sub when it’s within a certain range of the surface.

A neat addition to the sub is its autonomous navigation code. [Ayman] whipped up some simple object avoidance routines, which rely on the Raspberry Pi’s camera. The code uses HSV values to track specific colored objects and avoid them, which proves more reliable than RGB as it allows tracking color in a largely brightness-independent manner.

Although we’ve featured other builds that use similar construction techniques, seeing a transparent submarine gliding through the water will always make us think of the incredible Open Source Underwater Glider that won the 2017 Hackaday Prize.

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