Instructables
Picture of Bluetooth Headset Hack
My mum wanted to play some music from my desktop computer on her stereo(which doesnt have usb support but has stereo jack audio input) - and I was looking for reasons to hack stuff.
so i took  old broken bluetooth headset (that my ex broke...bla bla ) and  hacked it to include a stereo jack - and now she just plugs it in and plays the tunes(audio streaming) :)  

Future improvements:
1. Write a computer program to include voice control so she can just change music or switch of the computer off from her room using a voice command.
2.Hack the stereo to charge the bluetooth headset without unpluging it. (she probably wont let me do that lol )
 
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Step 1: Schematic

Picture of Schematic
This is the circuit diagram

Step 2: Items needed

Picture of Items needed
You are going to need: 
1. Bluetooth headset 
2.Stereo jack(3.5mm)
3.Soldering iron and wire 
5.Hot glue gun 
4.Thin wire 
5.General tools - e.g wire stripper 

Step 6: ...

Solder two wires to the stereo jack
- bridging the top 2 connections for left and right(black wire ) - then ground wire on third connection (white wire)

This is because the bluetooth headset has only two wires(mono output instead off stereo left and right ) 
*You might also want to snip off the microphone wires for privacy - but I didn't because I actually need that microphone for future hacks 
tshaw1411 months ago
great idea, did it with a stereo set I got at the discount store, works great. hooked them up with rca jacks instead so it would plug into my vintage stereo. I love bringing the 1960's and 2013 together.
dex3844 (author)  tshaw1410 months ago
nice, glad you could use my idea :)
twyeth23 days ago

great ible mate, i just have one problem with mine, my phone picks up the bluetooth kit for calls but wont allow me to play music via bluetooth to the same kit, the phone does allow music to be played through bluetooth just wont pick it up as a device for music

dex3844 (author)  twyeth17 days ago

thanks, its probably the headset you are using.. have you tried using a pc ?

twyeth dex384417 days ago
Yeah I have tried my pc arms that picks it up for VOIP but struggles to let me use it for music purposes, unless using VLC player instead of media player
dmarinho13 months ago
rseth17 months ago

the Bluetooth is connect as only voice in desktop and mobile both. it wont play through that bluetooth . any solutions?

If you are using Android try the "BTmono" app. It will spoof media audio as voice audio and allow it to play through the headset. The sound won't be much better than phone call quality, though.

dex3844 (author)  rseth17 months ago

hi, try another headset and see if that plays - and what headset do you have by the way ?

d-instructor8 months ago

dex - I have a stereo BT headset and would like to hookup a stereo jack to it so that i can use this to plug my stereo and also use this BT headset as usual when not in use with stereo. Please help.

dex3844 (author)  d-instructor8 months ago

which stereo BT headset do u have ?... you mean like some sort of way to remove the stereo jack when you don't need it /

d-instructor8 months ago

I had this idea in mind and I am glad you did this to reality.

There are 3 major benefits of this idea:


  1. You can turn your desktop/laptop/cellphone to play music wirelessly on other stereo speakers (with audio jack) once BT paired wit this device.
  2. You can turn your car stereo into BT stereo.
  3. Those who would like to play music wirelessly using their android smartphone can use 'BT mono' android app.

Great job and nice gift for your mother! please don't forget to post your next idea to program this for voice control and charging the device :)

dex3844 (author)  d-instructor8 months ago

thanks glad you liked it :)

dex3844 (author) 9 months ago
nice, so yours is stereo..which bluetooth speakers did you use?
muddog159 months ago
I am going to hack my Bluetooth speaker bar this way only I am going to have a cable coming off of it and have a switch to turn off the internal speakers on the sound bar.
muddog159 months ago
I just keep mine plugged in all the time so it doesn't drain the battery.
muddog159 months ago
I used RCA as well.
Pesoen1 year ago
In the headset, wich wire goes with the black wire of the stereo jack? the red one or the black one?
dex3844 (author)  Pesoen1 year ago
Since the headset is mono - it doesn't matter - the black to black or the other way round will work the same
Pesoen dex38441 year ago
Thanks man! now it's working fine! This guy it's a genius!
dex3844 (author)  Pesoen1 year ago
no problem - glad I could help :)
Pesoen1 year ago
And the the "bridge" is just soldering one wire to each conection and then soldering both to another wire?
dex3844 (author)  Pesoen1 year ago
yes it is - its just effectively making the connections into one
so i did it and it doesnt work only because my phone wont find it as a media player. it only works for the actual headset. any ideas about that?
why would your phone see it as a media player. It is simply a "bluetooth speaker". connect it exactly the same way as you would connect a headset over bluetooth, only instead of the headset producing the sound, you are having the headset pass sound into your stereo Aux port.

If the complaint is that after you connect it, your music does not come out, then that is a setting (or even limitation) of your phone. Phones expect a "headset" to be used for phone calls, not music, and may not even support playing anything other than phone calls through them. check your phone settings and see if there is an option for "primary sound device". If not, your phone will only understand how to send music through something it understands as headphones, the headphone jack, or an A2DP bluetooth device (stereo bluetooth for music).
dex3844 (author)  tylermthehippie1 year ago
great that it works to begin with but i dont know of a way to make your phone detect it as a 'media player' - sorry cudnt help you there but you could always use your computer :)
Gomex192 years ago
Amazing idea, glad to see it worked for you and other people. But if you make that 3.5mm Male into a 3.5mm Female, you can plu ANY headphones you want into it or you can put a small aux cable into it to get the same effect you have ^.^ just saying
dex3844 (author)  Gomex192 years ago
In theory it should work fine, but the sound level and quality would be affected more because of the increased resistance of the headphones or the aux cable- but that could be fixed by having a better bluetooth headset and adding an amplifier for the headphones,: still gud idea though and glad you like it
ashokaji2 years ago
pls help me how to send files without internet to a long distance
dex3844 (author)  ashokaji2 years ago
How long of a distance are we talking
Very cool! Great idea! LOVE IT! Thanks!
Jr.20122 years ago
So if my pc doesn't have inbuilt bluetooth I would follow all these steps but with the bluetooth dongle then make another one for a stereo but with the stereo jack? Sorry if this sounds like the dumbest question but I dont know how the pc would stream your music to the stereo.
thanks in advance
dex3844 (author)  Jr.20122 years ago
na its not a dumb question... and if u connect the dongle ..streaming settings should appear in volume control options (wat operating system do u have ?)
Jr.2012 dex38442 years ago
I have windows 7.
dex3844 (author)  Jr.20122 years ago
bluetoothheadset streaming option should be in sound controls under playback :)
Great! Can the headset be also used as audio input to the PC? Say, for an electric guitar? :P
dex3844 (author)  ianmartorell2 years ago
yes ofcourse...but theres the issue of sound quality ....
Really? How much worse would it be? Guitar jacks are mono anyway
dex3844 (author)  ianmartorell2 years ago
depending on the headset..since the guitar is mono too i reckon its not that bad anyway
Irwind Kee2 years ago
done, i use for my car.... its great
DSC00897.JPG
dex3844 (author)  Irwind Kee2 years ago
great :) - ur headset stereo ?
no.. its mono, just for picking up the phone. this thing help me a lot when i was driving and much more better than before
shad0w192 years ago
great..........
techboy4112 years ago
Bonne idée! je peu le pairer avec un cell.
dex3844 (author)  techboy4112 years ago
merci, content que je pourrais aider :)
cest tres gentil de ta part
dex3844 (author)  techboy4112 years ago
merci :)
gemimile3 years ago
can you pair it with another headset???
dex3844 (author)  gemimile3 years ago
how do u mean ? - i dint know you an pair a headset with another headset
elabz3 years ago

dex3844, I applaud the spirit!
(but there's a problem with implementation : )  )

The most obvious being that it's not longer a stereo, so we ought to call it "on her mono"  as opposed to "on her stereo" :) Seriously though, you're not supposed to just bridge the left and right channels. It's a task that requires an op amp and some circuitry but at the very least there should be resistors from the common wire to both left and right. I think in 10K range but you may need to play with the values in attempt to mitigate the impedance mismatch between the stereo's output and the bluetooth's mic. Which mismatch might also explain the bad quality.  Also, a phone headset (BT or otherwise) would only be designed to cover frequency range of 300 to  3,400Hz  which is a FAR cry from what you need to actually enjoy the output of that stereo (I mean, mono :) )

Anyhow, keep up great job hacking things, I'm with you on that! 
elabz elabz3 years ago

I re-read my comment and it made no sense to me either :) , so I had to draw it. All three resistors are 10K or can try a few values as low as 600Ohm if the volume is too low at 10K. This is what I meant:
Schematic-LR.jpg
dex3844 (author)  elabz3 years ago
aha thanks - tried the 10k's and volume was too low so i had to up the headset volume to max which drains its battery - i'l play around with the low values like 600ohm :) - and questions : why are you not supposed to just bridge the channels without an opamp ?
and as for the impendance mismatch - the stereo has its own amp and eq - so wudnt that kind of match the mic? (hey am only 1st year electronics so go easy on me lol )
-i also think the frequecy range accounts for the bad quality

thanks for the insight :)
elabz dex38443 years ago

Actually, you are correct - you're taking the output after the stereo's amp, not the line level output. In that case the proper solution would be even more complicated :)  - you'd need transformers to de-couple the channels from one another.

You're not supposed to just bridge the left and right channels because you're then connecting outputs of two different amplifiers. So a situation may arise where the left channel is trying to drive it's speaker (headphone's earplug) low while the other one would at the same time try to drive it's speaker (earplug) high.  In the end you'll overload both amps and you'll get neither correct high nor low.

If you have those resistors in place, at the very least that would assure that the amplitudes of signals (low and high) are separated by whatever is the voltage drop on those resistors. In other words, the low would still inhibit the high but just not as much as when you just bridged them.

As far as trying to match impedances, the difference is so big that probably no passive circuitry would do it anyhow: the headphones are in 40Ohm range whereas the electret mic of that Bluetooth headset is in 10K+ range.

So, try to play with those resistors to see what's the best quality / channel separation you can get, keeping in mind that the limitation of the phone line bandwidth set forth some 100+ years ago (300 to 3400 Hz) still applies. In other words, best you can ever get is the quality of music on hold you sometimes hear when you call some busy establishment.

Cheers!


Crucio elabz3 years ago
elabz says:
"You're not supposed to just bridge the left and right channels because you're then connecting outputs of two different amplifiers. So a situation may arise where the left channel is trying to drive it's speaker (headphone's earplug) low while the other one would at the same time try to drive it's speaker (earplug) high. In the end you'll overload both amps and you'll get neither correct high nor low."


Please excuse me if I'm wrong, but, logically, that doesn't apply here, because the source (Bluetooth device) is mono, so there's only one (mono) output. Isn't it, then, safe to connect the single op-amp output to two channels?
elabz Crucio3 years ago
Crucio, you make a good point. Silly me, I got this circuit in reverse! We are not using the BT headset as input, we're using it as output. My bad. Yes, you're correct, bridging L and R won't be a big deal on the input end. Thanks for the correction!
mastelios3 years ago
Really nice and clever idea!
dex3844 (author)  mastelios3 years ago
thanks :)
Nice project, I did a similar one a few years back, but slapped it in an altoids tins and added just the jack so i could plug in headphones. The audio is horrible since its only a 44k audio transfer for voice not music, and alot of devices won't play music to em unless they have a2dp which is on stereo bluetooth devices. Just given some bg on the subject-
Nick
dex3844 (author)  nickstewartroc3 years ago
gud - and true 44k is horrible for music :)
dagob3 years ago
You can always use a fm trasmitter to stream audio from pc to stereo. Those Fm transmitters has a short range bu you an hack it and extend its antena this way you have enougth range to use it inside your home.
Pax883 years ago
Ok so I did this bluetooth hack but the sound quality is horrible... could it be because the bluetooth was a cheapo?
dex3844 (author)  Pax883 years ago
yes most likely and the range of your bluetooth dongle
Pax88 dex38443 years ago
Thanks Dex. Also the only way I know how to stream music to a headset is with my jail broken iPhone is there any other way to stream music to a headset?
if you have a mac, its incredibly easy, pair the headset with your computer, and go to sound settings and you can select sound out as the bluetooth device.

I also agree with the horrible sound quality, kind of disappointing
wow that was incredibly easy..... now I wish it was that easy to stream from my idevices to it without jail breaking.... thanks for your help
mnc3 years ago
is this really stereo ?
dex3844 (author)  mnc3 years ago
No my headset only supports mono - but some headsets are stereo :)
mnc dex38443 years ago
nice though. :) i'll try with my nokia hedset, it's also mono i suppose.
dex3844 (author)  mnc3 years ago
when you are done it'd be nice to post a video of your replication :)
mnc dex38443 years ago
sure!, i'll let you know.
Hi, This is a nice ible, and i would love to know how do u manage to keep the bluetooth headset getting charge without unplugging it from the audio jack.

Having said that, i was wondering why would some one transmit audio from one device to another to listen to it, when the first device can also do the job with exceptional quality?

thanks.
dex3844 (author)  muhammajunaid3 years ago
To charge without unpluging I would have to hack the audio jack and route some power to it - more details am still working on it

And why I would want to transmit audio from device 1 to device 2 - in my case, having my music on my computer is more convenient since I can store alot of tracks,add and delete easily - but since the physical computer is downstairs and stereo system upstairs - streaming is easier than burning cds or buying an mp3 player - and just for the love of hacking, why not give an old bluetooth headset a second life :)
I know some of the plantronics headsets can charge and still be utilized at the same time. I have one of them. I also have 2 jabra headsets that turn off to charge... So it could be tricky for some of them.
dex3844 (author)  t_roy_m13 years ago
Great - which specific headsets are these - would like to hack them :)
I have 2 of the Jabra bt125. They are an older model, but i just found them on eBay, so they are still out there. They are fairly inexpensive. The downside would be that they turn off when charging, unless you can find a way around it.

The Plantronics is the m100. It does stay on when charging, which i think would be easier to work with. The downside is that is more expensive. I know it is still a current model, so it may be easier to find locally.

I stumbled across this article because I am trying to find a solution for handsfree in my car without all the installation necessary for other implementations. The downside is that these bluetooth headsets won't do stereo... Maybe I'll hack a stereo headset...
dex3844 (author)  t_roy_m13 years ago
Might try to find the plantronics headset cheaply - and yea the stereo one definatly have better sound quality :)
Well, trying to do it in a car, I'd rather have stereo audio... Because the ones for phone calls are only mono. It would be nice to sit in my car and stream audio from my phone with no cables.

I like the Plantronics. Works well for phone calls at least, lol.
dex3844 (author)  t_roy_m13 years ago
yea true - stereo ones are worth it lol
It might be as easy as linking the battery in paralell with the audio connection.

A diode willo probable be needed to keep the charge moving in the righ t way.
dex3844 (author)  PaulReynolds3 years ago
Already tried that but as soon as a charge is introduced it goes to charging mode -
might bypass the battery entirely and just run run on external power source :)
kprichard3 years ago
I thought of this a while ago, and I have been wanting to do it for so long. I'm glad that you have given me a proof of concept. If my old headset is "too broken" for this hack, I might even go buy a new cheapie to hack. Thanks.
dex3844 (author)  kprichard3 years ago
Thanks and am glad I helped :)
E_MAN3 years ago
This is cool! How is the sound quality compared to a cable?
dex3844 (author)  E_MAN3 years ago
sound quality isnt that great for music as compared to cable bvut have yet to try a stereo headset
mnabil3 years ago
that is so tremendously good :D do you have any video for that while it working i just need to test if there is any noise between pc and sound system
dex3844 (author)  mnabil3 years ago
thanks alot - and no i have'nt got video - but I can tell you that the headset i have is mono at 16 bits - so its not that great but some headsets are better and stereo and can be hacked just as easily :)
Torolix3 years ago
Hey, im working on this little hack and i have two small question, i bridged the two top connector on my 3,5mm jack and then soldered that wire to the two wires from the bluetooth headset, the white one (ground) is it supposed to go somwhere? :P
dex3844 (author)  Torolix3 years ago
Hey sorry my bad I should have included a circuit diagram on my instructable - but I'l do it now

to answer your question
1.when you bridge the two wires top wires - solder that wire to one of the wires from the headset
2. then solder the other wire (ground) - from your jack to the other wire from your bluetooth headset
hope this helps :)
schematic.png
Torolix dex38443 years ago
Ah thank you! I will remake mine as my jack was missing all wires and i was unsure if i solder at the rigth points, also my bluetooth is wired the following way:

It appears i can bypass the whole ground wire at this point or is one of the speaker cables actually the ground? :)

PS: thanks for helping a utter noob :D


bt.png
dex3844 (author)  Torolix3 years ago
just join the 2 wires(speaker wires) from the bluetooth headset to the 2 wires from the audio jack ( the whole ground wire doesnt realy matter)

PS: if you need more help I can do a video of the whole process ( just havent done 1 yet coz I havent got a good camera) :)
Torolix dex38443 years ago
Got it now ! im gonna dig up a new jack and post the result :) ty again!
dex3844 (author)  Torolix3 years ago
good - looking forward to seeing your result :)
jjure dex38443 years ago
I wanted something like this to play audiobooks from MP3 player on plantronics headset.

Bought this http://www.amazon.ca/gp/offer-listing/B004J2TPSI/ref=dp_olp_0?ie=UTF8&redirect=true&condition=all device, but they don't seen to pair. Lights flashing, but nothing else happens.

How do you pair devices without screens?
dex3844 (author)  jjure3 years ago
I don't know if i understand you correctly - but you want to transmit from your mp3 player to your plantronics bluetooth headset - if that the case then most bluetooth devices have a pairing button (normally the 'on' button ) which you press and hold when pluging in - there should be a blinking light
then press the pairing button on your plantronics headset until it blink usualy red and blue - and then the 2 should pair and tadaa music

i havent used these 2 devices that you have but after 'googling' - these videos might help (also I could not find videos on the devices you have but these might work the same way)

http://www.youtube.com/watch?v=0PkwOfczoHs


http://www.youtube.com/watch?v=pM0GCVDj7ac&feature=related


hope this helps :)
jjure dex38443 years ago
Thanks. Still no luck. I guess my devices are not compatible.
dex3844 (author)  jjure3 years ago
Maybe dats the issue - which plantronics headset do you have - and might be worth it to try another headset :)
Where you bridge the two wires should go to one wire on the Bluetooth and the white wire should go to the other wire on the Bluetooth(The two wires from the speaker should be soldered to the jack's two wires)
Capfl2k53 years ago
Dude thats awesome! I got a few spares i might sacrifice one just for this.
dex3844 (author)  Capfl2k53 years ago
Thanks - i'd like to see some replications :)
Excellent idea
dex3844 (author)  ankit.varshney3 years ago
Thanks :)
thegeeke3 years ago
For voice control, look up a program called "shoot". I got it awhile ago, so I don't remember the website. It's pretty good, and it's free! (Which is even better!)
dex3844 (author)  thegeeke3 years ago
Thanks thegeeke I will definately check it out instead of reinventing the wheel :)
No problem. You have to have a very basic understanding of coding (the program uses xml files as it's "dictonary"), but you seem like you know more than enough for that.
dex3844 (author)  thegeeke3 years ago
i cant seem to make this software work in windows 7 damn
Hmmm... I am using it on vista, but did you try running it in compatability mode? If that still doesn't fix it, I'm sure that there are others like it out there.
dex3844 (author)  thegeeke3 years ago
yes i did try that - but am posting a question on the forums now
If your Win7 is 64 bit you will never get compatability - vista is 32 bit
dex3844 (author)  Ericc8153 years ago
i do have win7 x64 damn lol
Good idea. That's the only trick that I know... and it usually doesn't work. Someone else might know another trick. Hope you can figure something out. :)
slickerboy3 years ago
Even considering that i have done this, i would have problems in the next step, which is making my pc recieves the sound of my wireless bluetooth headset. Because i've already tried and i could make the pc detect the haedset but it wouldn't recieved any sound from it. I done this with the windows vista software, did you use any other software especific? If yes, which did you use?
dex3844 (author)  slickerboy3 years ago
the goal is to send audio from pc to headset - i did mine from windows 7 but can be done in window vista

if you have already paired your headset with your pc , go to sound settings and set bluetooth headset as primary playback device or default playback device.

i've googled abit and it seems this is easier on vista sp2 :D
jeanle1er3 years ago
vraiment simple!
mais surtout
VRAIMENT BIEN!!!!!

excellente idée!!!
dex3844 (author)  jeanle1er3 years ago
Merci beaucoup !! :)
SinAmos3 years ago
I was going to do this, but because of it lacking stereo, I decided against it. Check this out.

http://www.dealextreme.com/p/bluetooth-2-0-a2dp-avrcp-stereo-music-receiver-and-handsfree-black-8422

This is totally worth hacking for doing your own bluetooth headsets. This is what I want to do in the future.
dex3844 (author)  SinAmos3 years ago
That bluetooth music reciever is nice - I might buy it now :)
el_gus3 years ago
is it stereo?
dex3844 (author)  el_gus3 years ago
my headset is mono - but some headsets are stereo
davidingram3 years ago
GREAT project, nice one. I did something similar the other night. Wanted to connect my Nexus One phone for bluetooth audio to my car stereo via aux. My phone has a bluetooth dock so i hacked into that to wire an aux lead out of it. :-). Talk about microsurgery!

Anyway, back to your project, how about trying this with a stereo bluetooth headset, plenty on Amazon for as low as 29 bucks. That'd be neat.
dex3844 (author)  davidingram3 years ago
Hacking is the way forward lol - you should have done an instructable for your work - and i will try a stereo headset when i get one :)
n audio port of music system is only output then hw did it get input of music from paired device???
plz rply
dex3844 (author)  Pranjal Joshi3 years ago
the stereo am using has input port - http://www.sony.co.uk/product/hfs-dab-systems/cmt-eh45dab

unless you mean your stereo has no input - in which case if it plays cassettes you can hack an mp3 cassette adapter - http://cgi.ebay.co.uk/ws/eBayISAPI.dll?VISuperSize&item=330604140157
cant we convert mono to stereo dude..????
dex3844 (author)  Pranjal Joshi3 years ago
you can if you have a stereo bluetooth headset - but mine is just mono
LifeWarrior3 years ago
This is a great idea, I had a old set of of stereo Motorola ht820's someone sat on and broke one of the headphones your 'ible gives me an amazing idea, I might just have to try.
dex3844 (author)  LifeWarrior3 years ago
lol - am glad am able to help :D
rocket9993 years ago
good! it's easy for me ,that i can do it
WhiteTune3 years ago
Thanks for this, had two spare headsets lying around, which I can now put to use! shame they're only mono but better than nothing:) grats on hackaday too :D
dex3844 (author)  WhiteTune3 years ago
Thanks White Tune and no probs - wish was stereo too :)