Motorized Faders Make An Awesome Volume Mixer For Your PC

These days, Windows has a moderately robust method for managing the volume across several applications. The only problem is that the controls for this are usually buried away. [CHWTT] found a way to make life easier by creating a physical mixer to handle volume levels instead.

The build relies on a piece of software called MIDI Mixer. It’s designed to control the volume levels of any application or audio device on a Windows system, and responds to MIDI commands. To suit this setup, [CHWTT] built a physical device to send the requisite MIDI commands to vary volume levels as desired. The build runs on an Arduino Micro. It’s set up to work with five motorized faders which are sold as replacements for the Behringer X32 mixer, which makes them very cheap to source. The motorized faders are driven by L293D motor controllers. There are also six additional push-buttons hooked up as well. The Micro reads the faders and sends the requisite MIDI commands to the attached PC over USB, and also moves the faders to different presets when commanded by the buttons.

If you’re a streamer, or just someone that often has multiple audio sources open at once, you might find a build like this remarkably useful. The use of motorized faders is a nice touch, too, easily allowing various presets to be recalled for different use cases.

We love seeing a build that goes to the effort to include motorized faders, there’s just something elegant and responsive about them.

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Thomas Edison May Have Discovered Graphene

Thomas Edison is well known for his inventions (even if you don’t agree he invented all of them). However, he also occasionally invented things he didn’t understand, so they had to be reinvented again later. The latest example comes from researchers at Rice University. While building a replica light bulb, they found that Thomas Edison may have accidentally created graphene while testing the original article.

Today, we know that applying a voltage to a carbon-based resistor and heating it up to over 2,000 °C can create turbostratic graphene. Edison used a carbon-based filament and could heat it to over 2,000 °C.

This reminds us of how, in the 1880s, Edison observed current flowing in one direction through a test light bulb that included a plate. However, he thought it was just a curiosity. It would be up to Fleming, in 1904, to figure it out and understand what could be done with it.

Naturally, Edison wouldn’t have known to look for graphene, how to look for it, or what to do with it if he found it. But it does boggle the mind to think about graphene appearing many decades earlier. Or maybe it would still be looking for a killer use. Certainly, as the Rice researchers note, this is one of the easier ways to make graphene.

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Cheap Smart Ring Becomes MIDI Controller

The Colmi R02 is one of the cheapest smart rings on the market. It costs about $20, and is remarkably easy to hack. [Floyd Steinberg] took advantage of this to turn it into a rather unique MIDI controller.

What makes the Colmi R02 somewhat unique is that the manufacturer did not try to lock out users from uploading their own firmware. You don’t even really need to “hack” it, since there is no code signing or encryption. You can just whip up your own firmware to make it do whatever you want.

To that end, [Floyd] set up the ring to act as a device for musical expression. When connected to a computer over Bluetooth, data from the ring’s accelerometer is converted into MIDI CC commands via a simple web app. The app allows the MIDI messages to be configured so they can control whatever parameter is desired. [Floyd] demonstrates the ring by using it to control filter cutoff frequencies on an outboard synthesizer, with great effect.

You could theoretically just strap an accelerometer to your hand with a microcontroller and achieve similar operation. However, the magic of this is that it costs only $20 and it’s already in a form factor that’s optimized for wearing on your finger. It’s hard to beat that.

Files are on GitHub for those eager to experiment. We’ve previously featured some hacks of this particular smart ring, too, with [Aaron Christophel’s] efforts directly inspiring this work.

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Secret Ingredients

We were talking on the podcast about rope. But not just any rope – especially non-stretchy rope for using in a mechanical context. The hack in question was a bicycle wheel that swapped out normal metal spokes for lighter and stronger high-density polypropylene weave, and if you can tension up a bike wheel and ride it around, you know it’s not your garden-variety twine.

Now, it just so happens that I’ve got basically the same stuff in my parts drawer: some 1 mm diamaeter Dyneema-brand rope. This is an amazing material. It’s rated to a breaking strength of 195 kg (430 lbs) yet it weighs just under one gram per meter, and if you buy the pre-stretched variant, it’s guaranteed to stretch less than 1% of its length under load. It’s flexible, wears well, and is basically in every way superior to braided steel wire.

It’s nearly magical, and it’s just what you need if you’re making a cable robot or anything where the extreme strength and non-elongation characteristic are important. It’s one of those things that there’s just no substitute for when you need it, and that’s why I have some in my secret-ingredients drawer. What else is in there? Some high-temperature tape, low-temperature solder, and ultra-light-weight M3 PEEK screws for airplane building.

But our conversation got me thinking about the parts, materials, and products that are unique: for which there is just no reasonable substitute. I’m sure the list gets longer the more interesting projects or disciplines that you’re into. What are your secret ingredients, and what’s the specific niche that they fit into?

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Surviving the RAM Price Squeeze With Linux In-Kernel Memory Compression

You’ve probably heard — we’re currently experiencing very high RAM prices due mostly to increased demand from AI data centers.

If you’ve been priced out of new RAM you are going to want to get as much value out of the RAM you already have as possible, and that’s where today’s hack comes in: if you’re on a Debian system read about ZRam for how to install and configure zram-tools to enable and manage the Linux kernel facilities that enable compressed RAM by integrating with the swap-enabled virtual memory system. We’ve seen it done with the Raspberry Pi, and the concept is the same.

Ubuntu users should check out systemd-zram-generator instead, and be aware that zram might already be installed and configured by default on your Ubuntu Desktop system.

If you’re interested in the history of in-kernel memory compression LWN.net has an old article covering the technology as it was gestating back in 2013: In-kernel Memory Compression. For those trying to get a grip on what has happened with RAM prices in recent history, a good place to track memory prices is memory.net and if you swing by you can see that a lot of RAM has gone up as much as four times in the last three or four months.

If you have any tips or hacks for memory compression on other platforms we would love to hear from you in the comments section!

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