Misc Hacks

4113 Articles

A man using a homemade vacuum apparatus to climb a wall

Scale Buildings With The Power Of Suction

November 28, 2021 by 30 Comments

Walls can’t hold [Elijah Cirioli]. The would-be superhero has been busy scaling the sides of buildings using his self-contained vacuum climbers. (Video embedded after the break.)

After being inspired by the winning project of an Air Force design challenge, our plain-clothed crusader got to work on a pair of prototype vacuum climbers. The wooden prototypes were an unexpected success, so work soon began on the models featured in the video after the break. The main improvements in this second version included using ¼ inch acrylic instead of plywood, as well as an improved gasket for a better seal against the imperfect exterior of many building walls.

While the system would still ultimately struggle with brick walls (and other imperfect surfaces), it performs more than adequately when ascending smoother concrete walls. And while the acrylic was a far better choice than the plywood, one of the acrylic panels still developed a fracture. Even so, the results speak for themselves, and we have to applaud the inventor’s seemingly unconditional trust in his equipment.

We haven’t seen a follow-up from [Elijah Cirioli] recently, so here’s hoping that he’s busy working on version three, and that he’s not stuck up a wall somewhere. In the meantime, check out how someone accomplished similar wall-climbing feats using salvaged microwave transformers.

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Magnus Effect Propels This Flettner Rotor Boat

November 27, 2021 by 13 Comments

The Magnus effect is a interesting and useful phenomena. [James Whomsley] from [Project Air] decided to put it to work on a small radio-controlled boat, successfully harnessing the effect. (Video, embedded after the break.)

The Magnus effect is an interesting thing, where fluid flowing over a rotating object generates an aerodynamic force at a right angle to the direction of the flow and the axis of rotation. (It’s why curveballs curve.) This can be used for propulsion on a boat, by spinning a tall cylinder called a Flettner rotor. This takes advantage of Magnus effect to generate thrust.

The boat uses a 3D-printed hull, sealed up with a leak sealer spray and lots of spray paint to avoid leaks.  In the center of the catamaran design, there’s a spinning rotor belt-driven by a brushless motor. Outside of the rotor for thrust, a simple rudder is used for steering.

With the rotor turning, the boat was able to successfully sail along with the benefit of the thrust generated from the wind. However, there were teething issues, with heavy winds quickly capsizing the boat. [James] realized that adding some proper keels would help avoid the boat tipping over.

We’ve seen [James] around these parts before, namely with the Magnus-effect aircraft that preceded this build.

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Cracking Open The Prince Floppy After The Purple Reign

November 23, 2021 by 21 Comments

Readers of a certain vintage will no doubt remember the time when Prince eschewed his royal position and became an unpronounceable symbol. People had no choice but to refer to him as TAFKAP, The Artist Formerly Known As Prince, and members of the music press were sent a 3.5″ floppy disk with a font file containing a single character — that gender-transcending shape that would soon become another one of Prince’s guitars. But it’s 2021, and now you can get it from the Internet Archive. Fun fact: the file wasn’t ever locked down. In fact, the symbol was available on Prince’s Compuserve and fan club CD-ROM.

While some people trawl auction sites for overalls and weird keyboards, others look for ridiculous items from the zeitgeist, like a copy of this floppy. Take [Anil Dash] for instance. [Anil] finally pulled the trigger after 15 years of debating this particular purchase. [Anil]’s interest was reignited after reading this analysis of whether the symbol could ever be put into Unicode. (Between being trademarked, a logo, and a personal character, it’s ineligible for inclusion.)

Earlier this week, [Anil] teamed up with Adafruit to extract the data from the floppy. The Twitter thread that ensued led readers to another old source of the font — the 1994 game Prince Interactive. We wonder if they broke out the oscilloscope, though it doesn’t look like it.

Thanks for the tip, [pt and limor]!

Cheating A Pedometer The Easy Way

November 20, 2021 by 9 Comments

These days, pedometers are integrated into just about every smartwatch on the market, and some of the dumber ones too. Tracking step counts has become a global pastime, and at times, a competitive one. However, any such competition can easily be gamed, as demonstrated by [Luc Volders].

Generally, all it takes to fool a basic pedometer is a gentle rhythmic jiggling motion of some sort. Cheaper devices will even register steps with little more than vague shaking.

[Luc] exploited this with basic machinery. A servo’s output shaft is fitted with a 3D printed cylinder, sized to allow a smartwatch to be attached as if to a wrist. Then, a Raspberry Pi Pico simply rocks the servo back and forth at regular intervals, and the watch begins counting these ersatz steps. Looking at the project as a whole, we’re betting [Luc] took some inspiration from old-fashioned automatic watch winders.

It’s hard to envision an important application for this technology. However, if one is in a friendly competition with friends who don’t scrutinize the results too closely, this would be an easy way to win.

Alternatively, consider building a pedometer to track your hamster’s exercise regime. If you’ve got your own exercise hacks on the go, drop us a line!

Light projected through prisms on to laser-cut letters submerged in water.

YOU Are A Projection Of Your Influences

November 18, 2021 by 5 Comments

Who are you? No, who are you really? You’re an amalgamation of influences from your family, your friends, the media, and the parasocial relationships you have with fictional characters. It’s okay; we all are. It can’t be helped that there’s a lot of it about.

[Kim Pimmel]’s YOU examines this question of identity in the form of  projected typography. YOU are solidly laser-cut at birth, but then come the influences — the water of everyday life that surrounds you, the lights that mask your dread or lay you bare, and the prisms of circumstance that twist the light into brilliant patterns that burn memories into your brain.

In this case, the light comes from a hacked camping headlamp that was past its prime. [Kim] laser-cut the letters from acrylic and submerged them in water, which can be manipulated to enhance the effect and mimic the turmoil of life. For added effect, [Kim] held prisms in the light’s path to refract it and cause the patterns to dance. Be sure to check it out after the break, and don’t forget to turn on the sound so you can hear [Kim]’s original composition.

Want to see more trippy typography? Check out this vector art that started as Perlin noise.

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A nixie tube next to a screenshot of a to-do list

Nixie Tube Indicator Tells You How Many Tasks You’ve Got Left To Do

November 17, 2021 by 10 Comments

For busy people, keeping track of all the tasks on your to-do list can be a daunting task in itself. Luckily there’s software to help you keep organized, but it’s always nice to have a physical artifact as well. Inspired by some beautiful nixie clock designs, [Bertrand Fan] decided to build a nixie indicator that tells him how many open items are on his to-do list, giving a shot of instant gratification as it counts down with each finished task.

The task-management part of this project is a on-line tool called Todoist. This program comes with a useful Web API that allows you to connect it your own software projects and exchange data. [Bert] wrote some code to extract the number of outstanding tasks from his to-do list and send it to an ESP8266 D1 Mini that drives the nixie tube. Mindful of the security implications of letting such a device connect directly to the internet, he set up a Mac Mini to act as a gateway, connecting to the ESP8266 through WiFi and to the Todoist servers through a VPN.

The little ESP board is sitting in a 3D-printed case, together with the nixie driver circuits and a socket to hold the tube. A ceramic tile glued to the front gives it a bit more of a sturdy, luxury feel to match the shiny glass and metal display device. The limitations of the nixie tube restrict the number of tasks indicated to nine, but we imagine this might actually be useful to help prevent [Bert] from overloading himself with too many tasks. After all, what’s the point of having this device if you can’t reach that satisfying “zero” at the end of the day?

Although nowadays nixie tubes are mostly associated with fancy clocks, we’ve seen them used in a variety of other uses, such as keeping track of 3D-printer filament, adding a display to a 1940s radio, or simply displaying nothing useful at all.

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Quick And (Not Very) Dirty Negative Voltage Supply

November 16, 2021 by 11 Comments

There comes a time in every hardware hacker’s career during which they first realize they need a negative voltage rail in their project. There also comes a time, usually ~10ms after realizing this, when they reach for the Art of Electronics to try and figure out how the heck to actually introduce subzero voltages into their design. As it turns out, there are a ton of ways to get the job done, from expensive power supplies to fancy regulators you can design, but if you’re lazy (like I am) you might just want a simple, nearly drop-in solution.

[Filip Piorski] has got you covered there. In a recent video, he demonstrates how to turn a “China Special” $1 buck converter from Ebay into a boost-buck converter, capable of acting as a negative voltage supply. He realized that by swapping around the inputs and outputs of the regulator you can essentially invert the potential produced. There are a few caveats, of course, including high start-up current and limited max. voltages, but he manages to circumvent some of them with a little clever rewiring and a bit of bodge work.

Of course, if you have strict power supply requirements you probably want to shell out the cash for a professionally-built one, or design one yourself that meets your exact needs. For the majority of us, a quick and easy solution like this will get the job done and allow us to focus on other aspects of the design without having to spend too much time worrying about the power supply. Of course, if power electronics design is your thing, we’ve got you covered there, too.

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