Misc Hacks

4016 Articles

Build An Easy Replica Of HAL 9000

October 27, 2023 by 31 Comments

Adafruit’s PropMaker Feather is a microcontroller board designed specifically for building props with electronic features. Thus, what better way to show it off than by building a nifty replica of the most menacing AI ever to roam this solar system? That’s right, it’s the Adafruit HAL9000 build!

Following the 80/20 rule, this version is intended to be reasonably authentic while remaining affordable and easy to build. It’s built around Adafruit’s existing Massive Red Arcade Button, which looks like a decent simulacra of HAL9000’s foreboding, perceptive lens. It’s placed in a case assembled from laser-cut acrylic, with a neat inkjet-printed label on top. Where previously, sound effects were courtesy of an Arduino Uno with a Wave Shield, this version uses the PropMaker Feather, based on the RP2040, instead. It’s actually possible to assemble with zero soldering thanks to quick-connect wires and screw terminals on the PropMaker Feather.

Fundamentally, if you’re building a simple prop that needs audio or LEDs, the PropMaker Feather could be a useful tool for the job. Alternatively, consider building a HAL replica with more capability, like controlling your home. Just don’t give it too much responsibility—we all know how that ends. Video after the break.

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Math Book Gets Real With Complex

October 22, 2023 by 22 Comments

The [Math Sorcerer] loves books. His latest acquisition is the famous Real and Complex Analysis, which is a very stout math book.  How stout? Well, there are several chapters on holomorphic functions, including how to do a Fourier transform on such a function. There’s also an appendix about Hausdorff’s maximality theorem. What are those? Beats us; read the book. You can also watch the short video review of the text below.

The author asserts right up front that the exponential function is “undoubtedly the most important function in mathematics.” Undoubtedly. [The Math Sorcerer’s] videos remind us of browsing a bookstore or a library. You don’t get a book summary as much as a preview of what’s in it, so you can decide if you want to read it.

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Stage Lighting Hack Keeps La Bohème From Becoming A Dumpster Fire

October 22, 2023 by 20 Comments

With all due respect to the Utah Opera’s production of La bohème, we just couldn’t resist poking a little fun at master electrician [David Smith]’s quick lighting hack for the opera. And who knew an opera from 1896 would need a garbage can fire? Live and learn.

In what appears to be a case of “The show must go on,” [David] was called on to improve an existing fire effect for one scene in the opera, which was reportedly a bit “artificial and distracting.” This is a pretty common problem in live productions of all types; it’s easy to throw light at a problem, but it’s often hard to make it both convincing and unobtrusive. Luckily, he had both the time to come up with something, and a kit full of goodies to make it happen. A balled-up strip of Neopixels provided the light, with an Arduino running some simple code to randomize the intensity and color of the RGBs. [David] stuck with the warm white, red, and green colors, to keep the color temperature about right for a fire, and drove the LEDs with a couple of MOSFETs that he keeps in his kit to fix busted dimmer packs.

The overall effect worked well, but the holes knocked in the side of the greatly abused garbage can let too much light out, making the effect distracting on stage. The remedy was simple: a cylinder of printer paper surrounding the LED tape. The paper not only acted as a diffuser but held the tape in place inside the can. The electrical crew ran two circuits to the can — one to keep the Arduino running throughout the show, and one to power the LED tape. The former made sure the audience didn’t see the microcontroller boot sequence, and the latter gave the electrician a way to control the effect from the dimmer console. The brief video below shows it in action during a rehearsal.

Hats off to [David] and the whole crew for the stagecraft heroics and for getting this thrown together so quickly.

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Bluetooth Device Visualizer Reveals Devices In Vicinity

October 21, 2023 by 2 Comments

Have you ever wondered how many Bluetooth devices are floating around you? You could use one of those creepy retail store Bluetooth tracking systems, or set your smartphone to scan. Alternatively, you could use the Bluetooth Devices Visualizer from [Jeremy Geppert].

The device was inspired by [Jeremy’s] trip to Hackaday Supercon 2022. Wanting to build something with LEDs that worked in a badge-like form factor, he set out on whipping up a device to scan and display a readout of Bluetooth devices in the immediate area.

The device is based on an ESP32 microcontroller, which provides the necessary Bluetooth hardware to scan for devices. It then displays the number of devices found using an 8 x 8 array of addressable LEDs. There is also a small OLED display on board for displaying relevant details to the device’s operation. The device neatly fits on a lanyard, and is more of an art project than anything else. It’s no wardriver, and details of devices found are not logged or stored in any way when the device is switched off.

With a variety of operational modes, it’s a fun way to get an idea of just how many Bluetooth devices are really out there these days. If you’ve got your own nifty Bluetooth hacks in the works, don’t hesitate to let us know!

 

PC Case Makes Portable Power Supply

October 21, 2023 by 4 Comments

Recently, we’ve seen a lot of semi-portable power stations. These have some big rechargeable battery and various connection options. [Dereksgc] wanted to make his own and decided the perfect housing would be a small PC tower case. (Video, embedded below.) It makes sense. There are plenty of easy-to-work front panel inserts, a power supply box with an AC cord (the power supply is long gone), and it is big enough to fit the battery. You can see the result in the video below.

The bulk of the work was installing power supply modules and a charge controller on floppy disk blank panels. The battery — a 50 Ah LiFePO4 unit — fits nicely in the bottom. Some of the buttons and connectors find use in the new incarnation.

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Building A Robot Bartender For Amazon

October 21, 2023 by 8 Comments

[Audax] built an unassuming side table with a party trick. It could retract a glass inside and fill it up with bourbon. The nifty device gained plenty of positive attention online, leading to a commission from Amazon to build a new version. Thus, [Audax] set about a redesign to create an even more impressive drink delivery system. (Video, embedded below.)

The story is very much one of refinement and optimization, focusing on the challenges of building a customer-facing device. With just six weeks to create the new rig, [Audax] had to figure out how to make the machine sleeker and more compact for its debut at a special event. To achieve this, he eschewed the original frame design made of aluminium extrusion, going for a 3D-printed design instead. The wire nest of the original version was then subsequently eliminated by an outsourced PCB design. Other new features included a mobile app for control and an easier way to adjust pour size, for bigger or smaller drinks as desired. For ease of use, activation is via an Amazon Alexa Skill.

As is so often the way, a last minute hurdle came up, prompting [Audax] to fly to Seattle to troubleshoot the rig on site. Nevertheless, the automatic drink server came good in the end, and delivered on its promise. Video after the break.

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The Pros And Cons Of Hydrofoils

October 17, 2023 by 24 Comments

Hydrofoils have fascinated naval architects and marine designers for years. Fitted with underwater wings, these designs traverse the waters at great speed with a minimum of drag. As with many innovative technologies, though, the use of hydrofoils is riddled with challenges that often offset the vast benefits they offer.

While hydrofoils promise a better marine transportation experience, their adoption hasn’t been smooth sailing. In this article, we’ll dive deep into the potential and pitfalls of hydrofoil designs, and look at the unique niches this technology serves today.

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