Misc Hacks

4032 Articles

The Seven-Segment Display That’s Also An Input Device

November 5, 2022 by 1 Comment

We’re used to seeing all manner of seven-segment displays, be they mechanical, electronic, or something in between. But what all these displays have in common is that they’re, you know, displays. Using them as inputs would just be crazy talk, right?

Perhaps, but we like where [Dave Ehnebuske] is going with “InSlide,” the seven-segment input device. The idea for this comes from the “DigiTag” display, which we covered back in October, and divides a standard seven-segment character into three vertical strips — two skinny ones for the outside vertical segments, and one wide strip holding the horizontal elements. By sliding these strips up and down relative to each other, the standard nine digits, plus a few other characters, can be composed.

[Dave]’s take on this theme started by building his display from laser-cut plywood pieces, which is a nice choice because of the good contrast between the white wood and the engraver segments. Next, he embedded rare earth magnets in the slides and installed seven Hall effect sensors in the frame. The sensors are connected to an Arduino Nano via a 74HC165 parallel-load shift register, which lets multiple modules be daisy-chained together. He also built an Arduino library to read the current state of the segments; it supports the full hexadecimal character set, or even duodecimal if you like.

[Dave] has shared the library, and it looks like you can get the build files for the mechanism from the original project. That’s good, because this looks ripe for hacking. It looks like it would be pretty easy to motorize a display like this by adding rack-and-pinion gearing and steppers — something like that could make an interesting clock.

Garage Door Opener Ejection Seat

November 5, 2022 by 16 Comments

[Scott Prints] had a familiar problem. His garage door opener was boring, and rattled around annoyingly in his car’s center console. This was obviously a major issue that needed to be dealt with. His solution was to install an ejector seat. Er, well, an ejector seat button. At least, that’s what it’s labeled. (That’s sure to be a great conversation starter for passengers.)

The end result looks slick and combines several build techniques. He started by taking measurements and 3D-printing a test piece for the center console nook. Turns out, that’s a more complicated shape than it seems. Rather than try to measure the exact angles and radii, Scott turned to the tried-and-true method of fiddling with the parameters and printing a second test. Close enough.

The coolest and most challenging element of the build was engraving and cutting the aluminum plate that forms the visible part of the build. Turns out, the online recommendations for milling aluminum are laughably optimistic when you don’t have an industrial CNC machine. Slower, shallower cuts got the job done, albeit slowly. A red paint-filled marker made the letters pop. The guts of the donor garage door opener are fitted into a 3d-printed shell, and then a Big Red Button threads into the print, holding the whole build together. A bit of solder later, and the project is done. Simple, effective, and very stylish! We approve. Come back after the break for the build video.
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Roll The Radioactive Dice For Truly Random D&D Play

November 2, 2022 by 22 Comments

When you have a bunch of people gathered around a table for a “Dungeons & Dragons” session, you have to expect that things are not always going to go smoothly. After all, people who willingly create and immerse themselves in an alternate reality where one bad roll of the dice can lead to the virtual death of a character they’ve spent months or years with can be traumatic. And with that trauma comes the search for the guilty — it’s the dice! It’s always the dice!

Eliminating that excuse, or at least making it statistically implausible, is the idea behind this radioactively random dice roller. It comes to us from [Science Shack] and uses radioactive decay to generate truly random numbers, as opposed to the pseudorandom number generators baked into most microcontrollers. The design is based on [AlphaPhoenix]’s muon-powered RNG, but with a significant twist: rather than depending on background radiation, [Science Shack] brought the power of uranium to the party.

They obtained a sample of autunite, a weird-looking phosphate mineral that contains a decent amount of uranium, perfect for stimulating the Geiger counter built into the dice roller. Autunite also has the advantage of looking very cool under UV light, taking on a ghostly “fuel rod glow,” in the [Homer Simpson] sense. The decay-powered RNG at the heart of this build is used to simulate throws of every standard D&D die, from a D4 to a D100. The laser-cut hardboard case holds all the controls and displays, and also has some strategically placed openings to gaze upon its glowing guts.

We really like the design, but we have to quibble with the handling of the uranium ore; true, the specific activity of autunite is probably pretty low, but it seems like at least some gloves would have been in order.

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Driving Three-Color E-Paper Pricetags With An Arduino

October 28, 2022 by 14 Comments

ePaper pricetags are becoming popular parts in the hacker community as a cheap way into tinkering with the technology. [Aaron Christophel] got his hands on a 4.4″ model with red, black, and white colors, and set about programming an ESP32 to drive the price tag instead.

The protocol the display uses was reverse-engineered by prompting the display to update via RF and monitoring the signals sent to between microcontrollers on the display’s control board. Once the protocol was understood, one of the microcontrollers could then be removed and replaced with an ESP32 for direct control. Implementing this takes some disassembly and some delicate soldering, but it’s nothing that should scare off an experienced hacker.

With the right code flashed to the ESP32, as available on Github, it’s possible to run the display directly. The hacked code does a great job driving the display, showing crisp lines and clean colors that indicate the e-Paper display is running properly.

We’ve seen [Aaron’s] work before in this area, when he hacked simpler two-color e-ink price tags. He’s also gone so far as creating entire wall displays out of salvaged displays, which is quite the sight. Video after the break.

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A Steam Engine For Empty Beer Cans

October 27, 2022 by 10 Comments

If Hero — the ancient Greek inventor — had been able to enjoy a beer after work, he might have pulled a trick like [BevCanTech] did: use it to create a simple steam engine. Of course, we aren’t sure why it has to be a beer can, but even with a soda can there is a fundamental problem: the can is open, assuming you’ve already enjoyed the beverage.

A pressure vessel with a big gaping hole in it isn’t much of a pressure vessel. The resealing process was actually quite simple. First, you bend back the tab to close up the opening as best you can. Next, you use cyanoacrylate glue and baking soda to seal up what’s left. We wondered if you could use epoxy, hot glue, or UV-curable resin. The top might get too hot for hot glue to last, but we aren’t sure.

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A Collection Of Websites That Look Like Desktops

October 27, 2022 by 15 Comments

Web design has come a long way since those halcyon days of Web 1.0. There are plenty of rules about how to make a clean and efficient website, but sometimes it’s more fun to throw them out and just be creative instead. In that vein, [Simone] has curated a wonderful collection of websites that emulate the computer desktop experience online.

The collection’s website very much fits this theme. Upon visiting, an Award BIOS screen flashes up. From there, we get a Windows 95-like interface full of links to other sites that emulate a computer desktop layout. There’s even a 3D screensaver that pops up if you mouse away for too long.

There’s Browso.app, which semi-accurately tells you information about your computer in a theme reminiscent of MacOS 9. Meanwhile, clicking on “It Is As if You Were Doing Work” will take you to a weird game that’s compelling in its replication of office banality. Nightwave Plaza offers exquisite vaporwave vibes, while others simply intend to faithfully recreate various OSes in a browser window.

It’s a fun collection of websites that go from the weirdly afamiliar to downright impressive recreations of former realities. It’s certainly fun to click around for a while and see what’s out there. We do love some good web ephemera around these parts!

Computing Fluidly

October 27, 2022 by 19 Comments

Computers come in many forms, depending on your definition. We’ve seen computers and computer gates built out of things as diverse as marbles, relays, and — of course — transistors. However, there are logic gate systems that use a property of moving fluids to form logic gates and a bistable element. That’s all the pieces you need to build a working computer.

It may sound far-fetched, but there have been general-purpose computers built using this technology. It is also used in specialized applications where fluids are already flowing, like shower heads, automotive transmissions, and in places where electronics are prone to misbehave. Many think the field will see a resurgence when we need to build logic at the molecular level for nanotech applications, too.

Basics

In its most basic form, a fluidic gate uses flow as a logic 1 and less flow to be a logic 0. Merging two streams together provides an OR gate. Using a supply stream that you can divert with a control stream provides a NOT function. Given enough inverters and OR gates, you can build everything else.

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