Author: Bryan Cockfield

1849 Articles

Learn To Play Guitar, Digitally

March 2, 2022 by 13 Comments

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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Split Flap Display Tells Us The Word

March 2, 2022 by 12 Comments

LED and LCD displays are a technological marvel. They’ve brought the price of televisions and monitors down to unheard-of levels since the days of CRTs, but this upside arguably comes with an aesthetic cost. When everything is covered in bland computer screens, the world tends to look a lot more monotonous. Not so several decades ago when there were many sharply contrasting ways of displaying information. One example of this different time comes to us by way of this split-flap display that [Erich] has been recreating.

Split-flap displays work by printing letters or numbers on a series of flaps that are attached to a spindle with a stepper motor. Each step of the motor turns the display by one character. They can be noisy and do require a large amount of maintenance compared to modern displays, but have some advantages as well. [Erich]’s version is built out of new acrylic and MDF, and uses an Arduino as the control board. A 3D printer and CNC machine keep the tolerances tight enough for the display to work smoothly and also enable him to expand the display as needed since each character display is fairly modular.

Right now, [Erich]’s display has 20 characters on two different rows and definitely brings us back to the bygone era where displays of this style would have been prominent in airports and train stations. This display uses a lot of the basics from another split flap display that we featured a few years ago but has some improvements. And, if you’d prefer restorations of old displays rather than modern incarnations, we have you covered there as well.

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Autonomous Mower Hits Snag

February 28, 2022 by 11 Comments

Interfacing technology and electronics with the real world is often fairly tricky. Complexity and edge cases work their way in to every corner of a project like this; just ask anyone who has ever tried to operate a rover on Mars, make a hydroponics garden, or build almost any robotics project. Even those of us who simply own a consumer-grade printer are flummoxed by the ways in which they can fail when manipulating single sheets of paper. This robotic lawnmower is no exception, driving its creator [TK] to extremes to get it to mow his lawn.

[TK] actually had a platform for his autonomous mower ready to go thanks to a previous build using this solar-powered robot to explore the Australian outback. Adding another motor to handle the grass trimming seemed simple at first and he set about wiring it all up and interfacing it to the robot. After the first iteration he found the robot was moving too fast to effectively cut the grass, so he added a more powerful cutting motor and a gearbox to help the mower crawl more slowly over the lawn. Disaster struck when his 3D printed mount for the steel cutting blades shattered, but with [TK] uninjured he pushed on with more improvements.

As it stands right now, the mower can effectively cut the grass moving forward even with the plastic-only cutting blades that [TK] is using now for safety reasons. The mower stripped its reverse gear so there still are some improvements to make before this robot is autonomously cutting the lawn without supervision. Normally we see lawnmowers retrofitted with robotics rather than robotics retrofitted with a lawnmower, but we’re excited to see any approach that lets us worry about one less household chore.

Thanks to [Rob] for the tip!

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3D Printed Climbing Holds, Now With Texture

February 26, 2022 by 4 Comments

Technology enables all kinds of possibilities to mold our environments in the way we best see fit. Plenty of ski resorts use snowmaking to extend their seasons, there are wave pools for surfing hundreds of miles away from oceans, and if you don’t live near any mountains you can build your own climbing wall as well. For the latter, many have turned to 3D printers to create more rock-like climbing grips but plastic doesn’t tend to behave the same as rock unless you do what [Giles Barton-Owen] did and incorporate salt into the prints.

For small manufacturers, typically the way that the rock texture is mimicked is by somehow incorporating sand, permanently, into the grip itself. This works well enough but is often too rough on climbers’ hands or otherwise doesn’t faithfully replicate a rock climbing experience. For these grips, instead of including sand, salt crystals of a particular size were added to a resin that was formed over the 3D printed grip. Once the resin cures substantially, the water-soluble salt can be washed away leaving a perfect texture to grab onto with chalked hands.

While this might not be a scalable method for large-scale climbing grip manufacturers, [Giles] hopes this method will help smaller operations or even DIY climbers to build more realistic grips without having to break the bank. In fact, he has already found some success at his local climbing gym using these grips. The method may be more difficult to scale for larger manufacturers but for anyone who wants to try it out themselves, all that’s needed for this build is a 3D printer, salt, and time.

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90s PC With Modern Parts Throws Many Off Track

February 24, 2022 by 17 Comments

When building a desktop computer, usually the budget is the limiting factor. Making sacrifices on one part in order to improve another without breaking the bank is part of the delicate balance of putting together a capable PC. If you’re lucky enough to have the sponsors that [Shank] has though, caution can be thrown to the wind with regards to price for some blisteringly fast parts. Putting them in a ’90s Hot Wheels case to build the ultimate sleeper PC, though, is just icing on the top.

This isn’t quite as simple as replacing a motherboard in a modern PC case, though. The Hot Wheels PC used a mini-ITX standard and is quite a bit smaller than most modern computers outside of something like a Mac Mini. To get the RTX 3060 GPU into the computer the shrouds needed to be removed to save space, plus an unusual 92mm form factor liquid CPU cooler needed to be installed. An equally obscure power supply was included to round out the Ryzen 9 build and after a lot of tinkering eventually all the parts were fitted into this retro case including the original, working floppy disk drive. After that some additional case modding was installed such as RGB lighting, wheels with spinning rims, a spoiler, and an exhaust pipe.

The main issue with this build was temperatures, and both the CPU and GPU were topping out at dangerously high temperatures until [Shank] installed a terrifying 11,000 RPM case fan. With a series of original CRT monitors to go along with this sleeper PC he can have up to 9 displays with surprisingly high video quality thanks to the fundamental properties of CRTs. The video is definitely worth a watch and falls right in line with some of [Shank]’s other console mods that he is famous for such as this handheld Virtual Boy.

Thanks to [Fast Rock Productions] for the tip!

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Prototype Robot For Omniwheel Bicycle

February 24, 2022 by No comments

For all its ability to advance modern society in basically every appreciable way, science still has yet to explain some seemingly basic concepts. One thing that still has a few holes in our understanding is the method by which a bicycle works. Surely, we know enough to build functional bicycles, but like gravity’s inclusion into the standard model we have yet to figure out a set of equations that govern all bicycles in the universe. To push our understanding of bicycles further, however, some are performing experiments like this self-balancing omniwheel bicycle robot.

Functional steering is important to get the bicycle going in the right direction, but it’s also critical for keeping the bike upright. This is where [James Bruton] is putting the omniwheel to the test. By placing it at the front of the bike, oriented perpendicularly to the direction of travel, he can both steer the bicycle robot and keep it balanced. This does take the computational efforts of an Arduino Mega paired with an inertial measurement unit but at the end [James] has a functional bicycle robot that he can use to experiment with the effects of different steering methods on bicycles.

While he doesn’t have a working omniwheel bicycle for a human yet, we at least hope that the build is an important step on the way to [James] or anyone else building a real bike with an omniwheel at the front. Hopefully this becomes a reality soon, but in the meantime we’ll have to be content with bicycles with normal wheels that can balance and drive themselves.

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Pressure Gauge Built In A Vacuum

February 23, 2022 by 7 Comments

Necessity might be the mother of all invention, but we often find that inventions around here are just as often driven by expensive off-the-shelf parts and a lack of willingness to spend top dollar for them. More often than not, we find people building their own tools or parts as if these high prices are a challenge instead of simply shrugging and ordering them from a supplier. The latest in those accepting the challenge of building their own parts is [Advanced Tinkering] who needed a specialty pressure gauge for a vacuum chamber.

In this specific case, the sensor itself is not too highly priced but the controller for it was the deal-breaker, so with a trusty Arduino in hand a custom gauge was fashioned once the sensor was acquired. This one uses an external analog-to-digital converter to interface with the sensor with 16-bit resolution, along with some circuitry to bring the ~8 V output of the sensor down to the 5 V required by the microcontroller. [Advanced Tinkering] wanted a custom live readout as well, so a 3D printed enclosure was built that includes both an LCD readout of the pressure and a screen with a graph of the pressure over time.

For anyone else making sensitive pressure measurements in a vacuum chamber, [Advanced Tinkering] made the project code available on a GitHub page. It’s a great solution to an otherwise overpriced part provided you have the time to build something custom. If you’re looking for something a little less delicate, though, take a look at this no-battery pressure sensor meant to ride along on a bicycle wheel.

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