Rockbox 4.0 Released

April 19, 2025 by John Elliot V 23 Comments

It’s traditional to launch new software on April Fool’s Day, which is when we heard that Rockbox 4.0 has been released. But, in this case, the venerable MP3 firmware actually did update after a long absence. It’s great to see that good old Rockbox is still kicking along. We first mentioned Rockbox here at Hackaday approaching 20 years ago. How time flies. There used to be a whole ‘scene’ around hacking Personal Media Players (PMPs), also known as “MP3 Players”.

We tracked down Rockbox contributor [Solomon Peachy] to ask for some simple advice: If someone wants to install Rockbox on a personal media player today, what hardware should they buy? [Solomon] referred us to the AIGO EROS Q / EROS K, which is the only compatible hardware still being manufactured and sold. Beyond that, if you want to buy compatible hardware, you’ll need to find some secondhand somewhere, such as eBay. See the Rockbox Wiki for supported hardware.

Smartphones and streaming services have subsumed the single-purpose personal media player. Will you put the new Rockbox on something? Let us know in the comments.

Freed At Last From Patents, Does Anyone Still Care About MP3?

February 8, 2025 by Maya Posch 99 Comments

The MP3 file format was always encumbered with patents, but as of 2017, the last patent finally expired. Although the format became synonymous with the digital music revolution that started in the late 90s, as an audio compression format there is an argument to be made that it has long since been superseded by better formats and other changes. [Ibrahim Diallo] makes that very argument in a recent blog post. In a world with super fast Internet speeds and the abstracting away of music formats behind streaming services, few people still care about MP3.

The last patents for the MP3 format expired in 2012 in the EU and 2017 in the US, ending many years of incessant legal sniping. For those of us learning of the wonders of MP3 back around ’98 through services like Napster or Limewire, MP3s meant downloading music on 56k dialup in a matter of minutes to hours rather than days to weeks with WAV, and with generally better quality than Microsoft’s WMA format at lower bitrates. When portable media players came onto the scene, they were called ‘MP3 players’, a name that stuck around.

But is MP3 really obsolete and best forgotten in the dustbin of history at this point? Would anyone care if computers dropped support for MP3 tomorrow?

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Audio On A Shoestring: DIY Your Own Studio-Grade Mic

January 14, 2025 by Heidi Ulrich 14 Comments

When it comes to DIY projects, nothing beats the thrill of crafting something that rivals expensive commercial products. In the microphone build video below, [Electronoobs] found himself inspired by DIY Perks earlier efforts. He took on the challenge of building a $20 high-quality microphone—a budget-friendly alternative to models priced at $500. The result: an engaging and educational journey that has it’s moments of triumph, it’s challenges, and of course, opportunities for improvement.

The core of the build lies in the JLI-2555 capsule, identical to those found in premium microphones. The process involves assembling a custom PCB for the amplifier, a selection of high-quality capacitors, and designing lightweight yet shielded wiring to minimize noise. [Electronoobs] also demonstrates the importance of a well-constructed metal mesh enclosure to eliminate interference, borrowing techniques like shaping mesh over a wooden template and insulating wires with ultra-thin enamel copper. While the final build does not quite reach the studio-quality level and looks of the referenced DIY Perks’ build, it is an impressive attempt to watch and learn from.

The project’s key challenge here would be achieving consistent audio quality. The microphone struggled with noise, low volume, and single-channel audio, until [Electronoobs] made smart modifications to the shielded wiring and amplification stages. Despite the hurdles, the build stands as an affordable alternative with significant potential for refinement in future iterations.

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Internals of the Blu-ray player, showing both the blu-ray drive and the custom PCBs

An Ingenious Blu-Ray Mini-Disk Player

June 1, 2024 by Arya Voronova 13 Comments

[befi] brings us a project as impressive as it is reminiscent of older times, a Blu-Ray mini disk player. Easily fitting inside a pocket like a 8 cm CD player would, this is a labour of love and, thanks to [befi]’s skills both in electronics and in using a dremel tool.

A BluRay drive was taken apart, for a start, and a lot of case parts were cut off; somehow, [befi] made it fit within an exceptionally tiny footprint, getting new structural parts printed instead, to a new size. The space savings let him put a fully custom F1C100S-powered board with a number of unique features, from a USB-SATA chip to talk to the BluRay drive, to USB pathway control for making sure the player can do USB gadget mode when desired.

There’s an OLED screen on the side, buttons for controlling the playback, power and battery management – this player is built to a high standard, ready for day-to-day use as your companion, in the world where leaving your smartphone as uninvolved in your life as possible is a surprisingly wise decision. As a fun aside, did you know that while 8 cm CDs and DVDs existed, 8 cm BluRay drives never made it to market? If you’re wondering how is it that [befi] has disks to play in this device, yes, he’s used a dremel here too.

Everything is open-sourced – 3D print files, the F1C100S board, and the Buildroot distribution complete with all the custom software used. If you want to build such a player, and we wouldn’t be surprised if you were, there’s more than enough resources for you to go off. And, if you’re thinking of building something else in a similar way, the Buildroot image will be hugely helpful.

Want some entertainment instead? Watch the video embedded below, the build journey is full of things you never knew you wanted to learn. This player is definitely a shining star on the dark path that is Blu-Ray, given that our most popular articles on Blu-Ray are about its problems.

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Building A Solar-Powered, Supercapacitor-Based Speaker

December 15, 2023 by Maya Posch 12 Comments

Inspired by many months of hours-long load shedding in South Africa, [JGJMatt] decided to make a portable speaker that can play tunes for hours on a single charge and even charge off the integrated solar panel to top the charge off. None of this should sound too surprising, but what differentiates this speaker is the use of two beefy 400 F, 2.7 V supercapacitors in series rather than a lithium-ion battery on the custom PCB with the Ti TPA2013D1 Class-D mono amplifier.

Insides of the speaker prior to stuffing and closing.

The reason for supercapacitors is two-fold. The first is that their lifespan is much longer than that of Li-ion batteries, the second that they can charge much faster. The disadvantages of supercapacitors come in the form of their lower energy density and linear discharge voltage. For the latter issue the TPA2301D1 amplifier has a built-in boost converter for an input range from 1.8 – 5.5 V, and despite the lower energy density a solid 6 hours of playback are claimed.

Beyond the exquisitely finished 3D printed PETG shell and TPU-based passive bass radiator, the functionality consists out of a single full-range speaker and an analog audio input (TRS jack and USB-C). To add Bluetooth support [JGJMatt] created a module consisting out of a Bluetooth module that connects to the USB-C port for both power and analog audio input.

Charging the speaker can be done via the USB-C port, as well as via the solar panel. This means that you can plug its USB-C port into e.g. a laptop’s USB-C port and (hopefully) charge it and play back music at the same time.

For those feeling like replicating this feat, the Gerbers, bill of materials, enclosure STLs, and everything else needed can be be found in the tutorial.

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Is That A Record Player In Your Pocket Or…

October 23, 2023 by Al Williams 26 Comments

If aliens visited the Earth, they might find our obsession with music hard to fathom. We have music in our homes, our cars, and our elevators. Musical performances draw huge crowds and create enormous fame for a select few musicians. These days, your music player of choice is probably the phone in your pocket. What our grandparents wouldn’t have done to have a pocket-sized music player. Wait…, it turns out they had them. [Rare Historical Photos] has pictures and other material related to the Mikiphone — a “pocket phonograph.” We don’t know how it sounded, but it is a fantastic piece of work visually. Actually, thanks to the [Stanford Archive of Recorded Sound], you can hear one of these rare machines playing in the video below. If only it were playing Toni Basil.

The device was made in the 1920s and had a decidedly strange tonearm. You wind it up with a gigantic key mechanism. There’s no electricity. A bakelite resonator became the speaker attached to the tone arm. The device was made in Switzerland by a company that started in music boxes. However, the design was the work of two brothers named Vadász.

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A Speaker With Dancing Ferrofluid

August 14, 2023 by Al Williams 2 Comments

A speaker project isn’t usually very different, but we couldn’t help but notice [Electronoob’s] latest speaker not for its audio performance but because it features dancing ferrofluid and is an unusual work of art. The housing is 3D printed and includes some translucent portions for LEDs.You can see and hear the speaker at work in the video below.

Apparently, not all ferrofluid is created equal. You can get just the fluid, but then you have to work up some sort of carrier fluid. You can also get the material already in a glass with a carrier fluid, which is a better option. Apparently, you can also get cheap material that is little more than iron filings suspended in a liquid. That’s not really ferrofluid.

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