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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Solar Cells As Art Form

When most of us approach a project, we have a certain problem to solve. 3D printing, microcontrollers, batteries, and all kinds of technologies are usually tools to accomplish some task. This is not necessarily true in the art world, though, where the intrinsic nature of these tools can be explored for their own sake rather than as a means to an end. The latest one that came across our desk is this light-powered sound generator.

The art piece looks a bit like a mobile with rotating arms, holding various small solar cells each connected to a speaker. As the arms pivot, the light falling on the cells changes which drives a specially-designed circuit connected to a speaker. The circuit acts as an oscillator, passing the changing voltage from the cell through various capacitors and transistors to produce changing tones in the speaker.

The effect of the rotating solar panels is not only oscillations from the speakers as the light changes, but oscillations in the sound of the speakers as they rotate towards and away from the observer. It’s a unique project and perfect for the art show it was in. It’s also not the only sound-focused art installation we’ve ever seen before, be sure to check out this one based on an ESP32.

Water Level Sensor Does Not Use Water Level Sensor

When interfacing with the real world, there are all kinds of sensors available which will readily communicate with your microcontroller of choice. Moisture, pH, humidity, temperature, location, light, and essentially every other physical phenomenon are readily measured with a matching sensor. But if you don’t have the exact sensor you need, it’s sometimes possible to use one sensor as a proxy for another.

[Brian Wyld] needed a way to monitor the level of a remote body of water but couldn’t use a pressure or surface-level sensor, so he used a sensor typically intended for geolocation instead. This particular unit, an STM-type device with a built-in accelerometer, is attached to a rotating arm with a float at one end. As the arm pivots, the microcontroller reports its position and some software converts the change in position to a water level. It’s also paired with a LoRa radio, allowing it to operate off-grid.

Whether there is a design requirement to use an esoteric sensor to measure something more common, or a personal hardware limitation brought about by a shallow parts drawer, there’s often a workaround like this one that can accomplish the job. Whatever the situation, we do appreciate hacking sensors into other types of sensors just as much as anything else.

A Primer For The Homebrew Game Boy Advance Scene

As video game systems pass into antiquity, some of them turn out to make excellent platforms for homebrew gaming. Not only does modern technology make it easier to interact with systems that are now comparatively underpowered and simpler, but the documentation available for older systems is often readily available as well, giving the community lots of options for exploration and creativity. The Game Boy Advance is becoming a popular platform for these sorts of independent game development, and this video shows exactly how you can get started too.

This tutorial starts with some explanation of how the GBA works. It offered developers several modes for the display, so this is the first choice a programmer must make when designing the game. From there it has a brief explanation of how to compile programs for the GBA and execute them, then it dives into actually writing the games themselves. There are a few examples that [3DSage] demonstrates here including examples for checking the operation of the code and hardware, some simple games, and also a detailed explanation the framebuffers and other hardware and software available when developing games for this console.

While the video is only 10 minutes long, we recommend watching it at three-quarters or half speed. It’s incredibly information-dense and anyone following along will likely need to pause several times. That being said, it’s an excellent primer for developing games for this platform and in general, especially since emulators are readily available so the original hardware isn’t needed. If you’d like to build something from an even more bygone era than the early 2000s, though, take a look at this tutorial for developing games on arcade cabinets.

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$800 Mountain Bike Seat Post Chopped In Two

For those unfamiliar with the sport of mountain biking, it’s a wild hobby that is rife with hacking. It started in the early 70s when the first dedicated mountain bikers were hacking road bikes together to ride on trails to varying levels of success, but only in the last decade or so have there been a lot of electronics appearing in various bike parts that we can all tinker with as well. This video discusses some of the downsides with a very expensive electronic seat post on a mountain bike, and attempts to solve its shortcomings by cutting it in half.

This build involves a dropper seat post, which is an adjustable seat for mountain biking that functions like an office chair. By pushing a button on the handlebars, the seat post can be rapidly adjusted up or down on-the-fly. Normally these seat posts use a cable to actuate, but this expensive version is wireless. The only problem is the battery will occasionally fly off when hitting big jumps, so [Berm Peak Express] decided to cut the existing proprietary battery system out and create a new housing for it. The new housing has a wired extension for the battery in its new location under the seat instead of behind it, and this gives it the clearance it arguably should have had from the manufacturer.

While not the most involved project of all time, it does take a certain mentality to take a hacksaw to a bike part that costs more than a large percentage of bicycles. It’s a niche product to be sure, but it also shows that some of the biggest annoyances with proprietary parts are not too difficult to overcome. And, it is interesting to see the ways that some people are hacking bikes outside of admittedly clever ebike conversions.

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Giant 3D Printer Aims To Produce Life-Sized Boat

As 3D printers become more ubiquitous, the number of custom designs and styles of printers has skyrocketed. From different printing materials and technologies to the movements of the printing head, we’ve seen all kinds of different takes on these tools. But one thing that has been largely limited to commercial and industrial use has been large print sizes —  leaving consumer level prints to be split into several pieces to fit together later. Not so with this giant 3D printer from [Ivan], though.

The design goals for this build are to print an entire boat that [Ivan] can captain himself, and additionally an entire go kart chassis in a single piece. It’s part of a contest between him and another YouTuber and as far as we can tell he’s well on his way to completing the challenge. The printer will be able to churn through 4 kg of filament per day, and has a printable volume of 1000x1000x1420 millimeters, or just shy of 1.5 cubic meters.

While this video is just the first step of building the frame and the printer guides, we can’t wait to see the next steps in the process. It’s one of the largest 3D printers we’ve ever seen, at least outside of printers designed for building entire houses out of concrete.

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Automate Your Desk With The Upsy Desky

It might be surprising for some, but humans actually evolved to be long-distance runners. We aren’t very fast comparatively, but no other animal can run for as long or as far as a human can. Sitting at a desk, on the other hand, is definitely not something that we’re adapted to do, so it’s important to take some measures to avoid many of the problems that arise for those that sit at a desk or computer most of the day. This build takes it to the extreme, not only implementing a standing desk but also a ton of automation for that desk as well.

This project is an improvement on a prior build by [TJ Horner] called the WiFi Standing Desk Controller. This new version has a catchier name, and uses an ESP32 to run the show. The enclosure is 3D printed and the control board includes USB-C and a hardware UART to interface with the controller. The real perks of this device are the automation, though. The desk can automatically lift if the user has been sitting too long, and could also automatically lift if it detects no one is home (to help keep a cat off of the desk, for example). It also includes presets for different users, and can export data to other software to help analyze sitting and standing patterns.

The controller design is open source and could be adapted to work on a wide-array of powered desks. As we’ve seen in the past, with the addition of a motor, even hand-crank standing desks can be upgraded. If you haven’t gotten into the standing desk trend yet, we hope that you are at least occasionally going for a run.