Pi Pico Powers Parts-Bin Audio Interface

June 20, 2025 by Tyler August 9 Comments

USB audio is great, but what if you needed to use it and had no budget? Well, depending on the contents of your parts bin, you might be able to use [Veyniac]’s Pico-Audio-Interface as a free (and libre! It’s GPL3.0) sound capture device.

In the project’s Reddit thread, [Veyniac] describes needing audio input for his homemade synth, but having no budget. Necessity being the mother of invention, rather than beg borrow or steal a device with a working sound card, he hacked together this lovely device. It shows up as a USB Audio Class 2.0 device so should work with just about anything, and offers 12-bit resolution and 4x oversampling to try and deal with USB noise with its 2-channel, 44.1 kHz sample rate.

Aside from the Pico, all you need is an LM324 op-amp IC and a handful of resistors and capacitors — [Veyniac] estimates about $10 to purchase the whole BOM. He claims that the captured audio sounds okay in his use, but can’t guarantee it will be for anyone else, noise being the fickle beast that it is. We figure that sounding “Okay” has got to be pretty good, given that you usually get what you pay for — and again, [Veyniac] did build this in a cave with a box of scraps. Well, except for the cave part. Probably.

While the goal here was not to rival a commercial USB sound card, we have seen projects to do tha t. We’re quite grateful to [Omadeira] for the tip, because this really is a hack. If you, too, want a share of our undying gratitude (which is still worth its weight in gold, despite fluctuations in the spot price of precious metals), send in a tip of your own.

Ben Eater Makes Computer Noises

June 19, 2025 by John Elliot V 7 Comments

When [Ben Eater] talks, hackers everywhere listen. In his latest video [Ben] shows us how to make computer noises using square waves and a 6502 microprocessor.

[Ben] uses the timer in the W65C22 Versatile Interface Adapter to generate the square waves which generate a tone. He then adds support for a new BEEP command into his MS BASIC interpreter. We covered [Ben Eater]’s MS BASIC here at Hackaday back in April, so definitely check that out if you missed it.

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A black PCB is shown, with an Arduino Nano mounted in the bottom left corner. The rest of the space on the PCB is used up by ten DIP integrated circuits and a few resistors and diodes. Several black and red wires connect different parts of the PCB.

Meowsic Keyboard MIDI Adapter Aims For Purrfection

June 14, 2025 by Aaron Beckendorf 3 Comments

Both small children and cats have a certain tendency to make loud noises at inopportune times, but what if there were a way to combine these auditory effects? This seems to have been the reasoning behind the creation of the Meowsic keyboard, a children’s keyboard that renders notes as cats’ meows. [Steve Gilissen], an appreciator of unusual electronic instruments, discovered that while there had been projects that turned the Meowsic keyboard into a MIDI output device, no one had yet added MIDI input to it, which of course spurred the creation of his Meowsic MIDI adapter.

The switches in the keys of the original keyboard form a matrix of rows and columns, so that creating a connection between a particular row and column plays a certain note. [Steve]’s plan was to have a microcontroller read MIDI input, then connect the appropriate row and column to play the desired note. The first step was to use a small length of wire to connect rows and columns, thus manually mapping connections to notes. After this tedious step, he designed a PCB that hosts an Arduino Nano to accept input, two MCP23017 GPIO expanders to give it enough outputs, and CD4066BE CMOS switches to trigger the connections.
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Two white, cylindrical speakers are shown. The sides and most of the tops of the speakers are covered in holes, and at the center of the top of each, there is a circular LCD display. The top of the speaker is marked “Braun.”

A Modern Take On Iconic Industrial Design

June 9, 2025 by Aaron Beckendorf 21 Comments

The Functionalist design philosophy that Dieter Rams brought to Braun from the 50s to the 90s still inspires the look of a few devices, including Apple’s iPod, Teenage Engineer’s synthesizers and recorders – and [2dom]’s IR7 streaming radio.

The streaming radio was inspired by Braun’s portable radios, particularly the SK2, TP1, and the T3 pocket radio. [2dom] started with the T3’s circular pattern of holes and experimented with several variations, finally settling on a cylindrical shape with a central display; a prototype with a low-power monochrome rectangular display was eventually rejected in favor of a circular LCD. The housing consists of four 3D-printed components: an upper and lower shell, a resonator for the speaker, and a knob for a rotary encoder.

Electronics-wise, an ESP32 handles the computing requirements, while the LCD and rotary encoder provide a user interface. For audio, it uses a VS1053 MP3 decoder, PAM8403 amplifier, and a wideband speaker, with an audio isolation transformer to clean up the audio. To reduce power consumption, a MOSFET cuts power to the peripheral components whenever the device is in sleep mode. The full design is available on GitHub.

The end result of this effort is a quite authentic-looking 21st-century adaptation of Rams’s original designs. If you’re interested in more Braun designs, check out this replica of one of their desk fans. We’ve also seen a restoration of one of Braun’s larger radios, the TS2.

A Yamaha smart speaker, now with external DAC.

Smart Speaker Gets Brain Surgery, Line-Out

May 2, 2025 by Tyler August 4 Comments

Sometimes you find a commercial product that is almost, but not exactly perfect for your needs. Your choices become: hack together a DIY replacement, or hack the commercial product to do what you need. [Daniel] chose door number two when he realized his Yamaha MusicCast smart speaker was perfect for his particular use case, except for its tragic lack of line out. A little surgery and a Digital-to-Analog Converter (DAC) breakout board solved that problem.

You can’t hear it in this image, but the headphones work.

[Daniel] first went diving into the datasheet of the Yamaha amplifier chip inside of the speaker, before realizing it did too much DSP for his taste. He did learn that the chip was getting i2s signals from the speaker’s wifi module. That’s a lucky break, since i2s is an open, well-known protocol. [Daniel] had an Adafruit DAC; he only needed to get the i2s signals from the smart speaker’s board to his breakout. That proved to be an adventure, but we’ll let [Daniel] tell the tale on his blog.

After a quick bit of OpenSCAD and 3D printing, the DAC was firmly mounted in its new home. Now [Daniel] has the exact audio-streaming-solution he wanted: Yamaha’s MusicCast, with line out to his own hi-fi.

[Daniel] and hackaday go way back: we featured his robot lawnmower in 2013. It’s great to see he’s still hacking. If you’d rather see what’s behind door number one, this roll-your-own smart speaker may whet your appetite.

Can Hackers Bring Jooki Back To Life?

March 30, 2025 by Tom Nardi 16 Comments

Another day, another Internet-connected gadget that gets abandoned by its creators. This time it’s Jooki — a screen-free audio player that let kids listen to music and stories by placing specific tokens on top of it. Parents would use a smartphone application to program what each token would do, and that way even very young children could independently select what they wanted to hear.

Well, until the company went bankrupt and shutdown their servers down, anyway. Security researcher [nuit] wrote into share the impressive work they’ve done so far to identify flaws in the Jooki’s firmware, in the hopes that it will inspire others in the community to start poking around inside these devices. While there’s unfortunately not enough here to return these devices to a fully-functional state today, there’s several promising leads.

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Yaydio, A Music Player For Kids

March 29, 2025 by Jenny List 6 Comments

Music consumption has followed a trend over the last decade or more of abandoning physical media for online or streaming alternatives. This can present a problem for young children however, for whom a simpler physical interface may be an easier way to play those tunes. Maintaining a library of CDs is not entirely convenient either, so [JakesMD] has created the Yaydio. It’s a music player for kids, that plays music when a card is inserted in its slot.

As you might expect, the cards themselves do not contain the music. Instead they are NFC cards, and the player starts the corresponding album from its SD card when one is detected. The hardware is simple enough, an Arduino Nano with modules for MP3 playback, NFC reading, seven segment display, and rotary encoder. The whole thing lives in a kid-friendly 3D printed case.

Some thought has been given to easily adding albums and assigning cards to them, making it easy to keep up with the youngster’s tastes. This isn’t the first such kid-friendly music player we’ve seen, but it’s certainly pretty neat.