Custom Calculator Brings Us Back To The 70s

There are certain design aesthetics from every era that manage to survive the fads of their time and live throughout history. Ancient Greek architecture is still drawn upon for design inspiration in modern buildings, the mid-century modern style from the 60s still inspires various designs of consumer goods, and the rounded, clean looking cars from the 90s are still highly desirable qualities in automotive design. For electronics, though, we like this 70s-inspired calculator that [Aaron] recently built.

The calculator hearkens back to the days of calculators like the HP-29C with its large buttons and dot-matrix display. [Aaron] built the case out of various woods with a screen angled towards the user, and it uses a LCD display similar to those found in antique calculators. The brain of the calculator is an Arduino which fits easily into the case, and [Aaron] also built the keyboard from scratch with Cherry MX-style mechanical keys soldered together into a custom shape.

The software to run the calculator is fairly straightforward, but we are most impressed with the woodworking, styling, and keyboard design in this build. [Aaron] is also still ironing out some bugs with the power supply as it uses a DC-DC converter to power the device from a single lithium battery. For those who are more fond of early 2000s graphing calculators instead, be sure to take a look at this graphing calculator arcade cabinet.

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Surprisingly Stomp-able Soft Switches

Competition sure brings out the brute in people, doesn’t it? So what do you do when you need a bunch of switches you can let people fist-pound or stomp on repeatedly without them taking damage? You could look to the guitar pedal industry and their tough latching switches, or you could simply build your own smash-resistant buttons as [wannabemadsci] has done.

The main thing about these switches is that they aren’t easily destroyed by shoes or angry fists. That’s because the shiny red push-me part of the button is made by cutting a foam ball in half.

Not easily crush-able Styrofoam, mind you — squishy, coated foam like an indoor football. This is mounted to the top of a sandwich made of hardboard and a couple pieces of easily-compressible foam from craft paintbrushes.

A brass washer is mounted to the middle of both pieces of hardboard, and these have wires soldered to them to read button presses. Then it’s just a matter of hooking it to a microcontroller like any other momentary.

There are all kinds of things you could cut in half for the top, like maybe tennis balls. Or, do what [Sprite_TM] did and use inverted plastic bowls.

Custom Macro Keyboard With Sweet Backlighting

From the smallest 60% keyboards for those with no desk space to keyboards with number pads for those doing data entry all day, there’s a keyboard size and shape for just about everyone. The only problem, even with the largest keyboards, is that they’re still fairly limited in what they can do. If you find yourself wishing for even more functionality, you might want to build something like this custom macro keyboard with built-in LED backlighting.

Rather than go with a standard mechanical keyboard switch like a Cherry MX, this build is based around TS26-2 pushbuttons with built-in LED lighting. [atkaper] only really needed one button for managing the mute button on MS Teams, but still built a total of eight switches into this keyboard which can all be individually programmed with different functions. The controller is an Arduino Leonardo and the enclosure was 3D printed.

Paired with the classic IBM Model M keyboard, this new macro keyboard adds plenty of functionality while also having control over LED backlighting. Macro keyboards are incredibly useful, especially with their ability to easily change function with control over the software that runs on them. The key to most builds is the 32U4 chip found in some Atmel microcontrollers which allows it to easily pass keyboard (and mouse) functionality to any computer its plugged in to.

Solving Grounding Issues On Switch Audio

Grounding of electrical systems is an often forgotten yet important design consideration. Issues with proper grounding can be complicated, confusing, and downright frustrating to solve. So much so that engineers can spend their entire careers specializing in grounding and bonding. [Bsilvereagle] was running into just this sort of frustrating problem while attempting to send audio from a Nintendo Switch into a PC, and documented some of the ways he attempted to fix a common problem known as a ground loop.

Ground loops occur when there are multiple paths to ground, especially in wires carrying signals. The low impedance path creates oscillations and ringing which is especially problematic for audio. When sending the Switch audio into a computer a loop like this formed. [Bsilvereagle] set about solving the issue using an isolating transformer. It took a few revisions, but eventually they settled on a circuit which improved sound quality tremendously. With that out of the way, the task of mixing the Switch audio with sources from other devices could finally proceed unimpeded.

As an investigation into a nuisance problem, this project goes into quite a bit of depth about ground loops and carrying signals over various transforming devices. It’s a great read if you’ve ever been stumped by a mysterious noise in a project. If you’ve never heard of a ground loop before, take a look at this guide to we featured a few years ago.

Learn To Play Guitar, Digitally

Learning to play a musical instrument takes a major time commitment. If you happened to be stuck inside your home at any point in the last two years, though, you may have had the opportunity that [Dmitriy] had to pick up a guitar and learn to play. Rather than stick with a traditional guitar, though, [Dmitriy] opted to build his own digital guitar which is packed with all kinds of features you won’t find in any Fender or Gibson.

The physical body of this unique instrument is entirely designed by [Dmitriy] out of 3D printed parts, and uses capacitive touch sensors for each of the notes on what would have been the guitar’s fretboard. The strings are also replaced with a set of six switches that can be strummed like a regular guitar, and are used to register when to play a note. After a few prototypes, everything was wired onto a custom PCB. The software side of this project is impressive as well; it involved creating custom firmware to register all of the button presses and transmit the information to a MIDI controller so that the guitar can communicate digitally with anything that supports MIDI.

To finish off the project, [Dmitriy] also added a wireless device as well as some other bonus features like an accelerometer, which can be used to augment the sound of the guitar in any way he can think of to program them. It’s one of the most innovative guitars we’ve seen since the prototype Noli smart guitar was unveiled last year, and this one is also on its way from prototype to market right now.

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Building Switching Points For A Backyard Railway

A home-built railway is one of the greatest things you could possibly use to shift loads around your farm. [Tim] and [Sandra] of YouTube channel [Way Out West] have just such a setup, but they needed some switching points to help direct carriages from one set of rails to another. Fabrication ensued!

The basic layout of the railway points.

The railway relies on very simple rails made with flat bar and angle iron, allowing the railway to be built without a lot of heavy blacksmithing work. For a light-duty home railway, these are more than strong enough to do the job.

As for the points, a simple V-shaped frog-and-blade design was used. The frog is the V-shaped section where the rails diverge into two directions, sitting in the center of the Y, while the blade is the part that moves to either side to guide the carriages in one way or t’other.

The blade consists of a 2.2 meter long piece of angle iron with a pin welded on, allowing it to pivot. Two pieces of flat bar were then welded together with a pin to make the frog. Two metal bushes were then forced into a wooden sleeper, allowing the blade to pivot as needed. The rails themselves are slightly kinked as needed and everything tacked down into sleepers with bolts and pipe pegs.

The design runs smoothly, much to [Tim]’s enjoyment. It’s a clear improvement over the earlier design we looked at least year.

There’s something inherently charming about a railway built with little more than wood, metal, and hammers. Seeing the little stone wagon run down the rails to bed in the sleepers is utterly joyful in a way that’s difficult to fully explain. Video after the break.
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Play Runescape IRL

Runescape is pushing nearly 21 years old, and while that’s quite a long time for a game to stay active with an engaged userbase, it’s also a long time for people to modify the game in all kinds of colorful ways. For some older games like Team Fortress 2 this means spinning up a bot to ruin servers, but for Runescape the hacks are a little more lighthearted and fun. Like this axe which allows [BigFancyBen] to play Runescape in real life.

This is more of an augmented reality hack which upgrades his normal human interface device from a simple keyboard and mouse to also include this axe. When the axe is manipulated in real life, the in-game axe can be used at the same time. There are a lot of layers to this one but essentially a Switch joycon is connected to the axe to sense motion, which relays the information on axe swings to an API via a Python script. A bot in the game then chops the virtual tree, which is reported back to the API which then reports it back to [BigFancyBen]’s viewscreen which is additionally streamed on Twitch.

While this started off as frustration with the game’s insistence on grinding in order to reach certain objectives, it seems that there are some fun ways of manipulating that game mechanic for the greater good. [BigFancyBen] originally said he would rather go to the gym than “click anymore rooftops”  this is quite the start on the full IRLScape world. Don’t forget that it’s equally possible to take this type of build in the opposite direction and control real-world things from inside a video game.

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