With the holiday season fast approaching, there’s a good chance that some well-meaning friend or relative might buy a toy musical instrument for your children, safe in the knowledge that they’ll never have to listen to the results! The sound from these cheap toy guitars is pretty terrible, partly because they’re just too small to tune to a pleasing guitar tuning, so [joekutz] decided to see if one could be turned into an electric ukulele instead.
[adblu] encountered the ever-present headphone problem with their Sennheiser Urbanite headphones – the cable broke. These headphones are decent, and despite the cable troubles, worth giving a new life to. Cable replacement is always an option, but [adblu] decided to see – what would it take to make these headphones wireless? And while they’re at it, just how much battery life could they get?
Armed with a CSR8635 Bluetooth audio receiver breakout module and a TP4056 charger, [adblu] went on rewiring the headphone internals. The CSR8635 already has a speaker amplifier inside, so connecting the headphones’ speakers didn’t require much effort – apart from general soldering difficulties, as [adblu]’s soldering iron was too large for the small pads on the BT module. They also found a 2400mAh battery, and fit it inside the headphone body after generous amounts of dremel work.
The result didn’t disappoint – not only does everything fit inside the headphone body, the headphones also provided 165 hours of music playback at varying volume. Electronics-wise, it really is that easy to retrofit your headphones with Bluetooth, but you can always go the extra mile and design an intricate set of custom PCBs! If firmware hacks are more to your liking, you can use a CSR8645 module for your build and then mod its firmware.
One of the most common ways to junk a pair of headphones is to damage the cord. Obviously, the lead can be repaired, but it involves busting out the soldering iron and can be tedious when dealing with the tiny little coated wires.
The hack is simple when applied to a classic pair of AKG K141 headphones. The little plastic casing on one earpiece is popped off, and replaced with a 3D-printed version that stoutly holds a female TRS jack in place. This can then be soldered up to the wiring inside the headphones.
With everything assembled, the headphones can now use an easily-replaceable cable, and one needn’t worry about having to bust out the soldering iron if the lead is damaged in future. It’s a particularly useful hack for those who use their headphones on the road, always throwing them into backpacks between gigs.
As more and more ports are removed from our smart devices, it seems that we have one of two options available for using peripherals: either buy a dongle to continue to use wired devices, or switch to Bluetooth and deal with perpetually maintaining batteries. If neither of these options suits you, though, there’s a third option available as [befinitiv] shows us in this build where he integrates a tiny solar panel to his earbud case to allow them to automatically charge themselves.
To start, he begins by taking apart the earbud case. For those who still haven’t tried out a set of these, they typically charge only when placed inside of their carrying case, which in his case also contains a small battery itself. Soldering wires directly to the battery allow for the battery to charge without as much electrical loss as he would have had if he had connected to the USB pins on the circuit board. Even then, the cell only generates a single volt so he needs a 5V boost converter to properly charge the battery. That came with its own problem, though, as it wouldn’t fit into the case properly. To solve that issue, he desoldered all of the components and deadbugged them together in order to fit the converter into a much smaller space without having to modify the case in any other way.
With all of that done and the small solar cell attached to the case, [befinitiv] has a smart solution to keep his wireless earbuds topped up without having to carry cables or dongles around every day. We’ve seen plenty of interesting solutions to the problem of various electronics manufacturers removing the ubiquitous 3.5 mm headphone jack too, and not all of them have dealt with this problem without certain other quirks arising as a result.
Working in a noisy office can be distracting. To combat the problem in his workplace [Rikard Anglerud] bought himself a pair of 3M ear defenders. They were good, but not quite good enough to completely extinguish the noise, so he inserted the drivers from a pair of cheap headphones and played a low-level white noise. This prototype proved effective, so he returned to the project and produced a much nicer pair that approach much more costly cans in their execution.
[Rikard’s] first set of headphones left something to be desired in the quality department. The second set followed with a pair of better-quality drivers sourced online, and more care was taken with cable routing and in their fitting. Finally some filler was used to remove the moulded 3M branding, and make them look more hi-fi than workwear.
From an audiophile perspective these cans might not approach a very high quality pair because their drivers are unlikely to be matched to the acoustic properties of their enclosures. But it sounds as though he’s achieved an adequate result despite that, and completely satisfied his need to exclude office noise.
Audiophiles have worked diligently to alert the rest of the world to products with superior sound quality, and to warn us away from expensive gimmicks that have middling features at best. Unfortunately, the downside of most high quality audio equipment is the sticker price. But with some soldering skills and a bit of hardware, you can build your own professional-level audio equipment around an ESP32 and impress almost any dedicated audiophile.
The list of features the tiny picoAUDIO board packs is impressive, starting with a 3.7 watt stereo amplifier and a second dedicated headphone amplifier. It also has all of the I/O you would expect something based on an ESP32 to have, such as I2S stereo DAC, an I2S microphone input, I2C GPIO extenders and, of course, a built-in MicroSD card reader. The audio quality is impressive too, and the project page has some MP3 files of audio recorded using this device that are worth listening to.
Whether you want the highest sound quality for your headphones while you listen to music, or you need a pocket-sized audio recording device, this might be the way to go. The project files are all available so you can build this from the ground up as well. Once you have that knocked out, you can move on to building your own speakers.
Military headphones, at least the older ones, are like few other sound reproducers. They are an expression of function over form, with an emphasis on robustness over operator comfort. Electrically they most often have high-impedance drivers and annoyingly proprietary connectors for whichever obscure radio system they were a part of.
[John Floren] has a HS-16A headset, the type used by the US military during the Vietnam war. It’s an antiquated design with a dual spring steel headband and on-the-ear ‘phones with no muff for comfort, and a quick bit of research finds that they can be had brand new in their 1960s packaging for somewhere around $20. Their connector is a pair of odd metal pins, and rather than doing what most of us would do and snipping the wire to fit something more useful, he hunted high and low for a TE Connectivity receptacle that would fit them. A short extension and a jack plug allowed him to use these slightly unusual cans.
This isn’t a special hack, but it’s still an interesting read because it sheds a bit of light upon these old-style headphones and reveals that they’re still available for anyone who wants their radio operating to have a retro feel. If you buy a set, you’ll probably still have them decades after more modern pairs have bitten the dust.