The speaker PCB inside of the speaker, with a flash chip ZIF holder soldered to the SPI flash pads on the PCB

Bluetooth Speaker Domesticated Through Firmware Mod

This might sound like a familiar problem – you get a Bluetooth speaker, and it sounds nice, but it also emits all kinds of weird sounds every now and then. [Oleg Kutkov] got himself a Sven PS460 speaker with FM radio functionality, but didn’t like that the “power on” sound was persistently loud with no respect for the volume setting, and the low battery notification sounds were bothersome. So, he disassembled the speaker, located a flash chip next to the processor, and started hacking.

Using a TL866 and minipro software, he dumped the firmware, and started probing it with binwalk. The default set of options didn’t show anything interesting, but he decided to look for sound file signatures specifically, and successfully found a collection of MP3 files! Proper extraction of these was a bit tricky, but he figured out how to get them out, and loaded the entire assortment into Audacity.

From there, he decided to merely make the annoying sounds quieter – negating the “no respect for the volume setting” aspect somewhat. After he exported the sound pack out of Audacity, the file became noticeably smaller, so he zero-padded it, and finally inserted it back into the firmware. Testing revealed that it worked just as intended! As a bonus, he replaced the “battery low” indicator sound with something that most of us would appreciate. Check out the demo video at the end of his write-up.

Domesticating your Bluetooth speakers tends to be called for. If you can’t do that for whatever reason, you can rebuild them into an audio receiver – or perhaps, build your own Bluetooth speakers, with aesthetics included and annoyance omitted from the start.

picture of finished mp3 player that uses a cartridge to select songs

An MP3 Player That Gives Off Nintendo Vibez

We’re definitely pretty fond of the DIY MP3 players here at Hackaday, but we don’t think we’ve seen one like CartridgeMP3 from [jpet26] before.

All the electrical components are what we’ve come to expect. [jpet26] uses the popular VS1053 decoder to read MP3 files stored on an SD card. He also includes a potentiometer for adjusting volume, a USB C port for power and programming, a headphone jack for the audio output, a general-purpose status LED, and an on/off switch.

But what really caught our attention is the form factor [jpet26] selected for his MP3 player. Though the MP3 files are stored on an SD card, he uses a cartridge interface, similar to that of a Nintendo 64 or Game Boy of yesteryear, to choose which MP3 to play from the SD card. The cartridge interface is tied to a few GPIO pins and by reading the status of each pin, the device determines which MP3 to select.

You could say that the cartridge is a little unnecessary, and we wouldn’t argue with you. The cartridge doesn’t actually store the MP3 files, the SD card does. It might make a bit more sense if the cartridge housed the SD card itself with a few select MP3s stored on the card. That would be a quirky way of sharing your favorite playlists with your friends. So, yeah some clumsy handshaking there, but who isn’t guilty of that from time to time? We like it and thought you might appreciate it as well.

Cool MP3 player, [jpet26]! May we suggest a speaker for V2? And maybe some flex cables.

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Daft Punk Word Clock Goes Stronger And Faster

What would you call a word clock that doesn’t tell time? The concept of a word clock is that all the words needed to be used are already there and then just selected. [Ben Combee] realized there were only 18 unique words to make up the song “Harder Faster Better Stronger” and with an extra PyBadge from Supercon 2021 on hand, it seems obvious to make a musical word clock of sorts.

The PyBadge is a 120 MHz ATSAMD51 based board with a screen, buttons, and a case that he 3d printed. To get reasonable sound quality while still fitting with the 2MB of flash storage on the device, MP3 compression was chosen. Since there was only one speaker, it was mixed down to mono and a lower bitrate, getting the size down to just 880KB. The mp3 is processed by the audiomp3 module in circuitpython with the volume level being sent to five NeoPixels to act as a VU. Getting the timing correct was the hardest part as the lyrics needed to be separated out and the timing figured out. Using Audacity’s label track feature, he had all the words tagged in the track and could export it into a format that could be massaged into a python friendly format.

The music and the text cues becoming desynchronized became a larger issue as the file plays. Increasing the MP3 buffer helped but the real trick was to peek inside the music decoder and figure out how many samples had been decoded and cue the words based on that, rather than the time since it wasn’t as accurate. All the code and files are up on his Hackaday.io page if you feel the need to make your own. If you’re sticking with Daft Punk, make sure to have your helmet ready when you rock. Though based on this summary of the compressibility of pop songs, there are a few other songs with a small enough number of unique words that they too could get the word clock treatment. Video after the break.

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Hackaday Podcast 078: Happy B-Day MP3, Eavesdropping On A Mars Probe, Shadowcasting 7-Segments, And A Spicy Commodore 64

Hackaday editors Elliot Williams and Mike Szczys go down the rabbit hole of hacky hacks. A talented group of radio amateurs have been recording and decoding the messages from Tianwen-1, the Mars probe launched by the Chinese National Space Administration on July 23rd. We don’t know exactly how magnets work, but know they do a great job of protecting your plasma cutter. You can’t beat the retro-chic look of a Commodore 64’s menu system, even if it’s tasked with something mundane like running a meat smoker. And take a walk with us down MP3’s memory lane.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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MP3 Is 25 Years Old!

In the streaming era, music is accessed from a variety of online services, ephemeral in nature and never living on board the device. However, the online audio revolution really kicked off with the development of one very special format. The subject of bitter raps and groundbreaking lawsuits, this development from Germany transformed the music industry as we know it. Twenty-five years on from the date the famous “.mp3” filename was chosen, we take a look back at how it came to be, and why it took over the world.

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A Wearable That Jives To The Beat Of Your Heart

We’re always searching for the coolest biohacking projects all over the web, so imagine our excitement when we ran across [marcvila333’s] wearable biometric monitor on Instructables. This was a combined effort between [Marc Vila], [Guillermo Stauffacher], and [Pau Carcell√©] as they were wrapping up the semester at their university. Their goal was to develop an integrated device that could modulate the wearer’s heart, and subsequently their mood and stress levels, using music.

Their device includes an LCD screen for user feedback, buttons for user input, an MP3 module, and a heart rate sensor module. The user can measure their heart rate and use the buttons to select the type of music they desire based on whether they would like to decrease or increase their heart rate. The science behind this phenomenon is still unknown, but the general sense is that different music can trigger different chemical signals in your brain, subsequently affecting your mood and other subtle physiological effects. I guess you can say that we tend to jive to the beat of our music.

It would be really cool to see their device automatically change the song to either lower or raise the user’s heart rate, making them calmer or more engaged. Maybe connect it to your tv? Currently, the user has to manually adjust the music, which might be a bit more inconvenient and could possibly lead to the placebo effect.

Either way; Cool project, team. Thanks for sharing!

DIY Pocket MP3 Player

When [Neutrino-1] saw DFRobot’s DFPlayer module, he decided he wanted to make his own retro MP3 player. This tiny module comes packed with a ton of interesting capabilities such as EQ adjustment, volume control, and a 3 watt amplifier amongst other things. It can even play ads in between songs, should you want such a thing.

Controlling the DFPlayer module is easy using serial commands from a microcontroller, making it a convenient subsystem in bigger projects, and a potential alternative to the popular VLSI chips or the hard to come by WT2003S IC. [Neutrino-1] does a good job walking readers through the build making it fairly easy to remix, reuse, and reshare.

With the hardware sorted, all you’ve got to do is flash the firmware and load up an SD card with some MP3s. There’s even a small Python GUI to help you get your new player up and running. [Neutrino-1] also introduces users to the U8g2 display library which he says is a bit more feature-rich than the common Adafruit SSD1306 library. Great job [Neutrino-1]!

While you’re here, take a look at some of our other MP3 projects.

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