Betta Aims To Bring Wire EDM To The Desktop

May 17, 2024 by 35 Comments

Just as practical nuclear fusion has been “only 20 years away” for the last 80 years or so, the promise of electrical discharge machining (EDM) in the home shop seems to always be just around the corner. It’s hard to understand why this is so — EDM is electrically and mechanically more complicated than traditional subtractive manufacturing techniques, so a plug-and-play EDM setup seems always just out of reach.

Or perhaps not, if this 3D printed 4-axis wire EDM machine catches on. It comes to us from [John] at Rack Robotics and is built around the Powercore EDM power supply that we’ve previously featured. Since wire EDM is a process that requires the workpiece to be completely immersed in a dielectric solution, the machine, dubbed “Betta,” is designed to fit inside a 10-gallon aquarium — get it?

A lot of thought went into keeping costs down. for example, rather than use expensive sealed motors, [John] engineered the double CoreXY platform to keep the motors out of the water bath using long drive shafts and sealed bearings. The wire handling mechanism is also quite simple, at least compared to commercial WEDM machines, and uses standard brass EDM wire. The video below shows the machine going to town of everything from aluminum to steel, with fantastic results on thin or thick stock.

While Rack Robotics is going to be offering complete kits, they’re also planning on open-sourcing all the build files. We’re eager to see where this leads, and if people will latch onto EDM with the same gusto they did with 3D printing.

Continue reading “Betta Aims To Bring Wire EDM To The Desktop” →

Running Four Brushless Motors With A Single Pi Pico

May 17, 2024 by 15 Comments

Sometimes, you have to drive four motors, and you need to do so with a certain level of control. You could throw a lot of parts at the problem, but you don’t necessarily have to. As [Shaun Crampton] demonstrates, you can run four brushless DC motors with a single Pi Pico.

[Shaun] set about developing a brushless motor controller from scratch with the Pico, relying on its PIO hardware and the TI DRV8313 — a handy three phase motor driver. Before he knew it, he was implementing field oriented control (FOC) in MicroPython, only to find that it was a little too slow for proper motor control work. He soon switched to C for the lower overheads, and was readily driving a brushless motor with his own code. Before long, he’d implemented torque limiting and PID speed control. He was even able to optimize things to the point where he had four motors hanging off a single Pi Pico, complete with Hall sensors for feedback.

The full story is well worth reading, as it goes from “Hello, World” all the way to the end of the project. If you’ve never experienced the joy of your own code getting a motor to spin, you might enjoy following in [Shaun’s] footsteps. Files are on GitHub for the curious.

We’ve seen a lot of motor controllers around here, many of which draw heavily from other projects online. It’s a great way to learn the basics of what is a very well established field. Meanwhile, if you’re cooking up your own project in this space, do drop us a line!

Customizable Bird Clock Sings The Hours By

May 16, 2024 by 7 Comments

For those looking to build their own clocks, one of the easiest ways to get started is with a pre-built module that uses a simple quartz oscillator and drives a set of hands. This generally doesn’t allow for much design of the clock besides the face, and since [core weaver] was building a clock that plays bird songs, a much more hackable clock driver was needed to interface with the rest of the electronics needed to build this project.

The clock hands for this build are driven by a double stepper motor which controls an hour and minute hand coaxially but independently. Originally an H-bridge circuit was designed for driving each of the hands but they draw so little current in this configuration that they could be driven by the microcontroller directly. A DS3231 clock is used for timekeeping connected to an ATMega128a which controls everything else. At the start of each hour the clock plays a corresponding bird song by communicating with an mp3 module, and a remote control can also be used to play the songs on demand.

Bird clocks are not an uncommon thing to find off the shelf, but this one adds a number of customizations that let it fly above those offerings, including customizing the sounds that play on the hour and adding remote control capabilities, a lithium battery charging circuit, and a number of other creature comforts. If you’re looking for even more unique bird clock designs this binary bird clock might fit the bill.

Continue reading “Customizable Bird Clock Sings The Hours By” →

Is The Frequency Domain A Real Place?

May 16, 2024 by 60 Comments

When analyzing data, one can use a variety of transformations on the data to massage it into a form that works better to tease out the information one is interested in. One such example is the application of the Fourier transform, which transforms a data set from the time domain into the frequency domain. Yet what is this frequency domain really? After enticing us to follow the white rabbit down a sudden plummet into the intangible question of what is and what is not, [lcamtuf] shows us around aspects of the frequency domain and kin.

One thing about the (discrete) Fourier transform is that it is excellent at analyzing data that consists out of sinewaves, such as audio signals. Yet when using the Fourier transform for square waves, the resulting output is less than useful, almost as if square waves are not real. Similarly, other transforms exist which work great for square waves, but turn everything else into meaningless harmonics. Starting with the discrete cosine transform (DCT), this gets us into Walsh and Hadamard matrices and the Walsh-Hadamard Transform (WHT), and their usage with transforming data from the time into the frequency domain.

Ultimately it would seem that the frequency domain is as real as it needs to be, albeit that its appearance is wholly dependent on the algorithm used to create it, whether this the DFT, DCT, WHT or something else entirely.

MIDI Spoon Piano Is Exactly What You Think It Is

May 16, 2024 by 6 Comments

Pianos traditionally had keys made out of ivory, but there’s a great way to avoid that if you want to save the elephants. You can build a keyboard using spoons, as demonstrated by [JCo Audio]. 

The build relies on twelve metal spoons to act as the keys of the instrument. They’re assembled into a wooden base in a manner roughly approximating the white and black keys of a conventional piano keyboard, using 3D-printed inserts to hold them in place. They’re hooked up to a Raspberry Pi Pico via a Pico Touch 2 board, which allows the spoons to be used as capacitive touch pads. Code from [todbot] was then used to take input from the 12 spoons and turn it into MIDI data. From there, hooking the Pi Pico up to a PC running some kind of MIDI synth is enough to make sounds.

It’s a simple build, but a functional one. Plus, it lets you ask your friends if they’d like to hear you play the spoons. The key here is to make a big show of hooking your instrument up to a laptop while explaining you’re not going to play the spoons a la the folk instrument, but you’re going to play a synth instead. Then you should use the spoon keyboard to play emulated spoon samples anyway. It’s called doubling down. Video after the break.

Continue reading “MIDI Spoon Piano Is Exactly What You Think It Is” →

Big Server Fan Becomes Fume Extractor

May 16, 2024 by 12 Comments

[Anthony Kouttron] wanted a fume extractor for his personal electronics lab, but he didn’t like the look of the cheap off-the-shelf units that he found. Ultimately, he figured it couldn’t be that hard to build own portable fume extractor instead.

The build is based around a mighty 110-watt centrifugal fan from an IBM server that’s rated at approximately 500 CFM. It’s a hefty unit, and it should be, given that it retails at over $200 on DigiKey. [Anthony] paired this fan with off-the-shelf HEPA and activated carbon filters. These are readily available from a variety of retailers. He didn’t want to DIY that part of the build, as the filter selection is critical to ensuring the unit actually captures the bad stuff in the air. He ended up building a custom power supply for the 12-volt fan, allowing it to run from common drill batteries for practicality’s sake.

Few of us have need for such a beefy fume extractor on the regular. Indeed, many hobbyists choose to ignore the risk from soldering or 3D printing fumes. Still, for those that want a beefy fume extractor they can build themselves, it might be worth looking over [Anthony]’s initial work.

We’ve seen some other great DIY fume extractors before, too. Even those that use drill batteries! If you’ve been cooking up your own solution, don’t hesitate to drop us a line!

Pump It Up Gets Homebrew GBA Port That Rocks

May 16, 2024 by 3 Comments

Pump It Up is a popular music video game that hails from South Korea. It’s similar in vibe to Dance Dance Revolution and In The Groove, but it has an extra arrow panel to make life harder. [Rodrigo Alfonso] loved it so much, he ported it to the Game Boy Advance.

The port looks fantastic, with all the fast-moving arrows and lovely sprite-based graphics you could dream of. But more than that, [Rodrigo’s] port is very fully featured. It doesn’t rely on tracked or sampled music, instead using actual GSM audio files for the songs.

It can also accept input from a PS/2 keyboard, and you can even do multiplayer over the GBA’s Wireless Adapter. What’s even cooler is that some of the game’s neat features have been broken out into separate libraries so other developers can use them. If you need a Serial Port library for the GBA, or a way to read the SD card on flash carts, [Rodrigo] has put the code on GitHub.

As you might have guessed, this isn’t the first time [Rodrigo] has pushed the limits on what Nintendo’s 32-bit handheld can do.

Continue reading “Pump It Up Gets Homebrew GBA Port That Rocks” →