[Sebastian Holzapfel] has designed an audio frontend (eurorack-pmod) for FPGA-based audio applications, which is designed to fit into a standard Eurorack enclosure. The project, released under CERN Open-Hardware License V2, is designed in KiCAD using the AK4619VN four-channel audio codec by Asahi Kasei microdevices. (And guess what folks, there’s plenty of those in stock!) Continue reading “An Open Hardware Eurorack Compatible Audio FPGA Front End”
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Making The AirPods Pro Case Repairable
Apple is often lauded for its design chops, but function is often sacrificed at the altar of form, particularly when repair is involved. [Ken Pillonel] has made it easier for everyone to replace the batteries or lightning port in the AirPods Pro case. (YouTube)
With such notable hacks as adding USB C to the iPhone already under his belt, [Pillonel] has turned his attention to fixing the notoriously poor repairability of AirPods and AirPods Pro, starting with the cases. While the batteries for these devices are available, replacement Lightning ports are not, and taking the housing apart for the case is an exercise in patience where the results can’t be guaranteed.
He designed a USB C replacement port for broken Lightning ports that is a perfect fit if you happen to get the case apart in one piece. If you’re less successful, he has you covered there too with a 3D printable enclosure replacement.
We sure miss the days of schematic proliferation here at Hackaday, but we know you don’t let glued enclosures or unobtainium parts stand in the way of repairs.
Audio Playback Toy For DSP Adventures
The declining costs of single-board computers has made serious computing power available for even the most trivial of tasks. It’s easy enough to slap a Raspberry Pi onto almost anything for nearly the same cost as a powerful 32-bit microcontroller platform, but this takes some of the fun out of projects for a few of us. Looking to get into the weeds can be a challenge as well, as [Michal Zalewski] demonstrates in this audio playback device he built from a simple 8-bit microcontroller.
The small toy takes audio input from a microphone through an op-amp and feeds this signal to an ADC within the AVR128DA28 microcontroller. The data is then stored on a separate memory chip ready to be played back through another op-amp paired with a speaker. This is where being familiar with the inner workings of the microcontroller comes in handy. By manipulating the interrupt routines in specific ways, the audio stored in memory can be played back at various speeds.
[Michal] intended this build to be a toy for one of his younger relatives, and for the price of a few ICs and buttons it does a pretty good job of turning a regular voice into a chipmunk voice like some commercial children’s toys some of us might remember. If the design aesthetics of this gadget look familiar, you may be thinking of his minimalist gaming device which we recently featured.
Converting A Sink To An Ultrasonic Cleaner
While ultrasonic cleaning might sound a bit like the “sonic shower” from Star Trek, this is actually one case where the futuristic-sounding technology predates its use in Sci-Fi. Ultrasonic cleaners have been around since the 50s and are used to clean all sorts of oddly-shaped or specialty objects by creating cavitation within a liquid that allows the surface of the object to be scoured. With the right equipment, these cleaning devices are fairly straightforward to build as well.
This ultrasonic cleaner by [Branchus Creations] started off as a standard stainless steel laundry sink, but with the addition of a few transducers it really turns up the volume. They are attached to the underside of the sink with a combination of a bolt and hard epoxy so that the sound is efficiently transmitted to the sink, but they’re not much use without driver boards to power them. These drivers take AC power and convert it to the DC required to generate the ultrasonic frequencies, and this build uses a driver for each of the transducers all wired up to a common control board for ease-of-use.
The results speak for themselves; a test is performed on a sheet of aluminum foil which quickly turns takes on a Swiss cheese appearance after just a couple minutes in the cleaner. It’s also shown cleaning rusty nails and a few other things as well. For other nontraditional cleaning methods, be sure to check out this wet media blast cabinet built from a 55-gallon drum.
Continue reading “Converting A Sink To An Ultrasonic Cleaner”
Surgery On An LED To Preserve Vintage Aesthetics
[Chris Jones] recently found himself in a pickle. An indicator LED off an old piece of stereo equipment had failed. It was a strange rectangular type for which he could source no modern substitute. Using a different LED would ruin the aesthetic. Thus, what else was [Chris] to do, but attempt surgery on an LED!
The first attempt was the simplest. [Chris] tried soldering a small SMD LED between the legs of the existing part, which was open circuit. It worked, but the light didn’t really propagate to the top of the LED’s plastic. It was too dim to do the job.
Unperturbed, [Chris] instead elected to cut the LED apart. he soldered the SMD LED to the original LED’s leads, inside its body this time. The top part of the plastic lens was then notched to fit snugly over the new SMD part. A bit of superglue then joined everything back together. The finished product looks a touch messy on the PCB. However, installed back inside the stereo, it’s a perfectly stealth fix that looks great.
Some will consider this fix frivolous and a waste of time. Others will appreciate the way it preserved the attractive retro look of a piece of vintage audio gear. In any case, we can all agree that modern LEDs are often a great replacement for older parts in many cases. If you’ve pulled off your own weird, oddball repair hacks, don’t hesitate to share us with them on the tipsline!
This green LED has stopped working. I think it's my fault – one leg shorted to the chassis while it was switched on and gave it 15V which it didn't like. It's an odd shape so we can't buy a new one. Can we fix it? 🧵 /1 pic.twitter.com/DX71Kk0TP5
— Chris Jones (@mjtech01) January 25, 2023
3D Printer Filament From Reel-to-Reel Audio Tapes
At heart, 3D printers are just machines that can melt plastic “wire” into interesting shapes. It’s well-known and oft-lamented that plastic of various sorts has been used to make all manner of household objects that might eventually end up in landfill or otherwise littering the environment. With these facts in mind and a surplus of tape, [brtv-z] decided to see if he could recycle some old reel-to-reel audio tapes into working filament for a 3D printer.

This isn’t the first time he has tried to print with unusual second-hand polymers, back in 2020 he pulled of a similar trick using VHS tape. Through experimentation, it was soon determined that seven strands of quarter-inch tape could be twisted together and fused to form a very tough-looking filament approximately 1.7 mm in diameter, which could then be fed into the unsuspecting printer.
The resulting prints are certainly different in a number of respects from using virgin filament. The material is porous, brittle and (unsurprisingly) rather rusty-looking, but it does have some interesting properties. It retains its magnetism and it catches the light in an unusual way. The video is after the break (in Russian, but YouTube does a reasonable job of generating English captions).
Don’t have any tape handy? No worries, we’ve also covered machines that can recycle plastic waste into filament before. In fact, two of them even won the 2022 Hackaday Prize. What else could you melt down that might otherwise be thrown away?
Continue reading “3D Printer Filament From Reel-to-Reel Audio Tapes”
AIOC: The Ham Radio All-In-One Cable For Audio And APRS
The Ham Radio All-in-one cable (AIOC) is a small PCB attachment for a popular series of radio transceivers which adds a USB-attached audio interface and virtual TTY port for programming and the push-to-talk function. The STM32F373 microcontroller (which, sadly is still hard to find in the usual channels) is a perfect fit for this application, with all the needed hardware resources.
With USB-C connectivity, the AIOC enumerates as a
sound card as well as a virtual serial device, so interfacing to practically any host computer should be plug-and-play. Connection to the radio uses 12mm separation 3.5mm and 2.5mm TRS connectors, so is compatible with at least the Baofeng UV-5R but likely many other cheap transceivers that have the same physical setup.
Instructions are provided to use the AIOC with Dire Wolf for easy access to APRS applications, which makes a nice out-of-the-box demo to get you going. APRS is not all about tracking things though since other applications can sit atop the APRS/AX.25 network, for example, HROT: the ham radio of things.
We’ve seen quite a few Baofeng (and related products) hacks, like this sketchy pile of wires allowing one to experiment with the guts of the radio for APRS. Of course, such cheap radio transceivers cut so many engineering corners that there are movements to ban their sale, so maybe a new batch of better radios from our friends in the East is on the horizon?
Thanks to [Hspil] for the tip!






