Reprogramming Bluetooth Headphones for Great Justice

Like a lot of mass-produced consumer goods, it turns out that the internal workings of Bluetooth headphones are the same across a lot of different brands. One common Bluetooth module is the CSR8645, which [lorf] realized was fairly common and (more importantly) fairly easy to modify. [lorf] was able to put together a toolkit to reprogram this Bluetooth module in almost all of these headphones.

This tip comes to us from [Tigox] who has already made good use of [lorf]’s software. Using the toolkit, he was able to reprogram his own Bluetooth headphones over a USB link to his computer. After downloading and running [lorf]’s program, he was able to modify the name of the device and, more importantly, was able to adjust the behavior of the microphone’s gain which allowed him to have a much more pleasant user experience.

Additionally, the new toolkit makes it possible to flash custom ROMs to CSR Bluetooth modules. This opens up all kinds of possibilities, including the potential to use a set of inexpensive headphones for purposes other than listening to music. The button presses and microphones can be re-purposed for virtually any task imaginable. Of course, you may be able to find cheaper Bluetooth devices to repurpose, but if you just need to adjust your headphones’ settings then this hack will be more useful.

[Featured and Thumbnail Image Source by JLab Audio LLC – jlabaudio.com, CC BY-SA 4.0]

Modified Baby Monitor Interrupts Your Groove in Case of Emergency

You try to be good, but the temptation to drown out the noise of parenthood with some great tunes is just too much to resist. The music washes over you, bringing you back to simpler times. But alas, once you plug in the kids started running amok, and now the house is on fire and there’s the cleaning up to do and all that paperwork. Maybe you should have tried modifying a baby monitor to interrupt your music in case of emergency?

Starting with an off-the-shelf baby monitor, [Ben Heck] takes us through the design goals and does a quick teardown of the circuit. A simple audio switching circuit is breadboarded using an ADG436 dual SPDT chip to allow either the baby monitor audio or music fed from your favorite source through to the output. [Ben] wisely chose the path of least resistance to detecting baby noise by using the volume indicating LEDs on the monitor. A 555 one-shot trips for a few seconds when there’s enough noise, which switches the music off and lets you listen in on [Junior]. The nice touch is that all the added components fit nicely in the roomy case and are powered off the monitor’s supply.

Maybe you’d prefer listening to the nippers less than watching them? In that case, this impromptu eye-in-the-sky baby camera might be a better choice.

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Iron Tips: Soldering Headphones and Enamel Wire

We’ve all had that treasured pair of headphones fail us. One moment we’re jamming out to our favorite song, then, betrayal. The right ear goes out. No wait. It’s back. No, damn, it’s gone. It works for a while and then no jiggling of the wire will bring it back. So we think to ourselves, we’ve soldered before. This is nothing. We’ll just splice the wire together.

So we open it up only to be faced with the worst imaginable configuration: little strands of copper enamel wire intertwined with nylon for some reason. How does a mortal solder this? First you try to untwine the nylon from the strands. It kind of works, but now the strands are all mangled and weird. Huh. Okay. well, you kind of twist them together and give a go at soldering. No dice. Next comes sandpaper, torches, and all sorts of work-a-rounds. None of them seem to work. The best you manage is sound in one ear. It’s time to give up.

Soldering this stuff is actually pretty easy. It just takes a bit of knowledge about how assembly line workers do it. Let’s take a look.

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High Impedance Headphones? They’re In The Can!

[George Trimble] likes to build crystal radios. The original crystal radio builders used high impedance headphones. In modern builds, you are as likely to include a powered amplifier to drive a speaker or normal headphones (which are usually around 4 to 16 ohms).

[George] builds his own speakers using chile cans, some wire, a few magnets, part of a Pepsi can (we are pretty sure someone will leave a comment that Coke cans sound better), and the iron core out of an audio transformer. You can see a very detailed video of the process, below.

There is a little woodworking and hot gluing involved. The result is decidedly homemade looking, but if you want to say you built it yourself (or, if you are a prepper trying to get ready to  rebuild after the apocalypse and you can’t find a cache of headphones) this might be just the ticket.

Most of the headphone hacks we see start with a pair of headphones. That’s a bit tautological, but the goal is usually to add features, not make the whole thing. It does give you some hacker cred, though, to be able to look at the other guy’s radio and say, “Oh. I see you used commercial headphones.”

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High-end Headphones Fixed with High-end CNC Machine

Warranty? We don’t need no stinking warranty! We’re hackers, and if you have access to a multi-million dollar CNC machine and 3D CAM software, you mill your own headphone replacement parts rather than accept a free handout from a manufacturer.

The headphones in question, Grado SR325s, are hand-built, high-end audiophile headphones, but [Huibert van Egmond] found that the gimbal holding the cups to the headband were loosening and falling out. He replicated the design of the original gimbal in CAM, generated the numeric code, and let his enormous Bridgeport milling machine loose on a big block of aluminum. The part was drilled and tapped on a small knee-mill, cut free from the backing material on a lathe, and bead-blasted to remove milling marks. A quick coat of spray paint – we’d have preferred powder coating or anodization – and the part was ready to go back on the headphones.

Sure, it’s overkill, but when you’ve got the tools, why not? And even a DIY CNC router could probably turn out a part like this – a lot slower, to be sure, but it’s still plausible.

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Noise Cancelling Speech Recogntion

If you are like us, you’ll read a bit more and smack your forehead. Amazon recently filed a patent. That isn’t really news, per se–they file lots of patents, including ones that cover clicking on a button to order something and taking pictures against white backgrounds (in a very specific way). However, this patent is not only a good idea, but one we were surprised didn’t arise out of the hacker community.

There can’t be an invention without a problem and the problem this one solves is a common one: While wearing noise cancelling headphones, you can’t hear things that you want to hear (like someone coming up behind you). The Amazon solution? Let the headphones monitor for programmable keywords and turn off noise cancellation in response to those words. We wonder if you could have a more sophisticated digital signal processor look for other cues like a car horn, a siren, or a scream.

We’ve talked about fixing commercial noise cancelling headphones before. If you don’t mind going low-tech, there’s always the easy way out, but those aren’t likely to accommodate speech recognition.

Ask Hackaday: Does Apple Know Jack About Headphones?

If you’ve watched the tech news these last few months, you probably have noticed the rumors that Apple is expected to dump the headphone jack on the upcoming iPhone 7. They’re not alone either. On the Android side, Motorola has announced the Moto Z will not have a jack. Chinese manufacturer LeEco has introduced several new phones sans phone jack. So what does this mean for all of us?

This isn’t the first time a cell phone company has tried to design out the headphone jack. Anyone remember HTC’s extUSB, which was used on the Android G1? Nokia tried it with their POP Port. Sony Ericsson’s attempt was the FastPort. Samsung tried a dizzying array of multi-pin connectors. HP/Palm used a magnetic adapter on their Veer. Apple themselves tried to reinvent the headphone jack by recessing it in the original iPhone, breaking compatibility with most of the offerings on the market. All of these manufacturers eventually went with the tried and true ⅛” headphone jack. Many of these connectors were switched over during an odd time in history where Bluetooth was overtaking wired “hands-free kits”, and phones were gaining the ability to play mp3 files.

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