An ATTiny GPU Fan Controller That Sticks

August 2, 2025 by Heidi Ulrich 14 Comments

When your GPU fan goes rogue with an unholy screech, you either shell out for a new one or you go full hacker mode. Well, [ashafq] did the latter. The result is a delightfully nerdy fan controller powered by an ATTiny85 and governed by a DS18B20 temperature sensor. We all know a silent workstation is golden, and there’s no fun in throwing money at an off-the-shelf solution. [ashafq]’s custom build transforms a whiny Radeon RX 550 into a cool, quiet operator. Best of all: it’s built from bits likely already in your junk drawer.

To challenge himself a bit, [ashafq] rolled his own temperature-triggered PWM logic using 1-wire protocol on an ATtiny85, all without libraries or bloated firmware. The fan’s speed only ramps up when the GPU gets toasty, just like it should. It’s efficient and clever, and that makes it a fine hack. The entire system runs off a scavenged 12V fan. He could have used a 3D printer, but decided to stick onto the card with double-sided tape. McGyver would approve.

The results don’t lie: idle temps at 40 °C, load peaking at 60 °C. Quieter than stock, smarter than stock, and way cheaper too. The double-sided tape may not last, but that leaves room for improvement. In case you want to start on it yourself, read the full write-up and feel inspired to build your own. Hackaday.io is ready for the documentation of your take on it.

Modifying fans is a tradition around here. Does it always take a processor? Nope.

Custom Bedroom Lighting Controlled By Alexa

August 2, 2025 by Lewin Day 3 Comments

[Arkandas] had a problem. They liked reading in bed, but their bedroom lamps weren’t cutting it—either too bright and direct, or too dim and diffuse. The solution was custom lighting, and a new project began.

The concept was simple—build a custom controller for a set of addressable LED lighting strips that would be installed in the bedroom. Specifically, in the headboard of the bed, providing controllable light directly where it was needed. The strips themselves were installed in aluminum channel with plastic diffusers to give a nice smooth light. [Arkandas] then tasked an ESP32 to control the strips, using the FastLED library to work with WS2812B LEDs, and also the Adafruit NeoPixel library for using SK6812 LEDs and their extra white channel. The ESP32 was set up to provide a web interface for direct control over the local network. [Arkandas] also made good use of the FauxmoESP library to enable the device to be controlled via Amazon Alexa, which fit nicely into their existing smarthome setup. Files are on Github for the curious.

The final build works well, creating a soft light in the habitable area of the bed that can also be readily controlled via voice commands or via web. We’ve seen the ESP32 do other great feats in this arena before, too, albeit of the more colorful variety. Meanwhile, if you’re cooking up your own smart lighting solutions, don’t hesitate to tell the tipsline!

Universal Control For The Last Mac You’d Ever Expect

August 1, 2025 by Tyler August 8 Comments

Universal control is a neat feature on Macintosh computers, allowing you to slide your mouse seamlessly from device to device. Of course you need a relatively recent version of MacOS to make it work, right? Not necessarily– thanks to [Bart Jackobs] MacFriends, universal control has come to the Macintosh Classic.

The Arduino is perfect for this purpose, but choosing it ruined a perfectly good pun and we can never forgive that.

Well, not exactly universal control, but similar functionality at any rate. [Bart] can slide his mouse from one side of his retina display over onto the glorious 512 x 342, 1-bit display of his Macintosh Classic, just as if the 68k powered antique was a modern device. As you might expect, the Motorola 68000 in that old Mac is getting a teensy bit of help– though sadly for our love of puns, from an Arduino Nano and not any kind of Teensy.

The Arduino is emulating a mouse and keyboard on the Apple Desktop Bus using code based on the abduino by [akuker]. [Bart]’s custom software on the modern Mac captures the mouse and keyboard inputs to pipe to the Arduino via USB serial. Apple’s Universal control doesn’t require a wired connection between the two machines, of course, but then, it doesn’t work on the Classic. One could imagine redoing this project for Bluetooth communication to have that a same Clarkian feeling of technological magic Apple has always wanted to convey– but nothing was wireless in 1990 except for telegrams and a handful of telephones, so the project is appropriate as-is.

As much as we might resent that micro-controller for ruining a pun, if you want to hook into the ADB– perhaps to use old peripherals with an emulated Macintosh— an Arduino will do the job. So would a Teensy, though, and then we’d have our pun.

Our thanks to [Bart Jakobs] for the tip. Don’t forget to send in your own: the endless maw of the tipsline is always hungry.

AI Code Review The Right Way

August 1, 2025 by Al Williams 29 Comments

Do you use a spell checker? We’ll guess you do. Would you use a button that just said “correct all spelling errors in document?” Hopefully not. Your word processor probably doesn’t even offer that as an option. Why? Because a spellchecker will reject things not in its dictionary (like Hackaday, maybe). It may guess the wrong word as the correct word. Of course, it also may miss things like “too” vs. “two.” So why would you just blindly accept AI code review? You wouldn’t, and that’s [Bill Mill’s] point with his recent tool made to help him do better code reviews.

He points out that he ignores most of the suggestions the tool outputs, but that it has saved him from some errors. Like a spellcheck, sometimes you just hit ignore. But at least you don’t have to check every single word.

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You Can Make Your Own Floppy Drive Cleaning Disks

August 1, 2025 by Lewin Day 11 Comments

Once upon a time, you could buy floppy drive cleaning disks at just about any stationary or computer store. These days, they’re harder to find. If you want to build one yourself, though, you might do well to follow [Gammitin]’s fine example.

[Gammitin] has been down this road before, having built head cleaning disks before. This time, a US patent was the inspiration. It basically indicated that the spinning cleaning disc inside should be made of spunbonded polyester or spunbonded olefin (such as Dupont Tyvek)—so those materials were sought out.

The project began with [Gammitin] disassembling a standard floppy disk down to its bare components. The spindle was then separated from the magnetic platter, and refitted with a disc of Tyvek material using super glue. The disk housing was then glued back together with more super glue, and labelled as a “Floppy Cleaning Disk.” Using the disk is as simple as putting a few drops of isopropyl alcohol on the Tyvek material, and inserting it into a drive. [Gammitin] tested it with an old Olivetti machine, and found it cleaned up the heads nicely.

Sometimes, when a commercial product ceases to exist, you can just make your own at home. This is a great example of that ethos. If you’re cooking up your own tools and accessories to keep your old machines running, we’d love to hear all about it on the tipsline!

Digital Guitar Of The Future Has No Strings

August 1, 2025 by Tyler August 39 Comments

Electric guitars are great, but they’re just so 20th century. You’d think decades of musicians riffing on the instrument would mean there are no hacks left in the humble axe. You’d think so, but you’d be wrong. [Michael], for one, has taken it upon himself to reinvent the electric guitar for the digital era.

Gone are the strings, and the frets have vanished as well. The neck of this guitar is one long custom PCB, looking very sleek with black solder mask. Gold pads serve as touch sensors to give tone data over i2c (from unspecified touch sensing chips) to the Amtel Mega 32u4 at the heart of the build.

With no strings, strumming won’t work, so a laptop-style touchpad serves instead. That means every user interaction with this guitar is with capacitive touch sensors talking i2c. The X and Y coordinates of the touch, along with pressure are sent to the processor over the i2c bus, triggering an interrupt and offering quite a bit of opportunity for sound control.

Said sound control is, of course, done in MIDI. This lets the guitar control a whole variety of synths and/or software, and of course [Michael] is using more futuristic-sounding synths than a pack of guitar samples. That said, what exactly goes on with the MIDI controls is left frustratingly vague. Obviously fretting provides note selection, but does the touchpad just send a “note start” command, or are the X, Y and pressure data used in interesting ways? Is there multitouch support? The video doesn’t say.

How, exactly, the obviously-plastic body of the guitar was manufactured is also left unsaid. Is it a large resin print? SLS? It looks injection-molded, but that makes no sense for a one-off prototype. On the other hand, it looks like he’s selling these, so it may very well be an injection-molded production case we’re seeing being assembled here, and not a prototype at all.

For all the video leaves us wanting more information, we can’t help but admit the end product both looks and sounds very cool. (Skip to the 4:50 mark in the embedded video to hear it in action.) The only thing that would improve it would be a hurdy-gurdy mode. Thanks to [Michael] for the tip, and remember we want to hear tips about all the weird and wonderful hacked-together instruments you make or find on the web.

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2025 One-Hertz Challenge: The Flip Disc Clock

August 1, 2025 by Lewin Day 1 Comment

Do you like buses, or do you just like the flippy-flappy displays they use to show route information? Either way, you’ll probably love the flip-disc clock created by [David Plass].

The build is based around four seven-segment flip disc displays. The modules in question are from Flipo.io. They use a hefty 0.5 amp pulse to create a magnetic field strong enough to flip the discs from one side to the other with coils placed underneath the fluro/black flipdots themselves. The modules are controlled by a Wemos D1, which uses Wi-Fi to query a NTP server to keep accurate time. It then drives the necessary segments to display the current time. The whole thing is assembled in what appears to be some kind of kitchen storage tub.

Notably, the clock flips a couple dots once every second to meet the requirements of our One-Hertz Challenge. This also makes it obvious that the clock is working when it would otherwise be static. However, [David] notes commenting out that part of the code at times, as it can be quite loud!

This clock has got fluro dots, it’s well-executed, and it’s a fine entry to the 2025 One-Hertz Challenge. We’ve also previously explored how these beautiful displays work in detail, too. Meanwhile, if you’re busy repurposing some other kind of mechanical display technology, don’t hesitate to let us know!