Car radio head unit that sends headset commands

Hmm, I need a headunit for the same functions.

AFAIK for controllling a smartphone over bluetooth it must support AVRCP for controlling and A2DP for audio.

So I found this unit: Sony MEX-BT3800U

Iam going to buy this soon (need to sell some stuff).

Hope this runs with my Kaiser

I think what you're looking for is something like this? It comes with a wireless strap that you can put on your steering wheel that gives you control over your device. Basic stuff like answering phone, play music, and move track forward and back. Plus, it uses a 3.5mm port, so no stupid bad quality FM radio. As long as Bluetooth is enabled, it automatically connects to the device. So all you gotta do is walk into the car.

BTW, I have this hooked up to my Pioneer stereo, using the P-BUS that all Pioneers have. I just needed a adapter. Not to confuse anyone, this needs a car stereo with a 3.5mm aux jack. You can usually get an adapter that plugs in the back where the CD changer would normally go, and avoid the terrible FM radio quality. Don't waste your time with FM radio adapters.
http://www.amazon.com/gp/product/B0011UIX2K/ref=oss_product

yeah i also need that for my relative who has the same problem about the Car radio head unit that sends headset commands

thanks!!

You can try with this one:
mytrendyphone.co.uk

Clarion DXZ588RUSB USB/MP3 Radio - Black

It should be fairly trivial to modify VWCDPIC (for Audi / Volkswagen / SEAT / Skoda) etc, to do this. I may look into doing this for my HTC HD2 soon, if no-one has done this yet.

For emulating the button pushes, on the TRRS I think you should just connect the lines to each TRR, and just leave them in input mode (high resistance). Then when you want to send a command, just pull the line down to ground. If you're worried about applying too much resistance, add a resistor between the micro and the tip or ring.

On my HTC headset:
Play/Pause/Phone - Pull the second ring down to ground (Mic line)
Previous Track - Pull the first ring down from 20kOhm to ~235 Ohm
Next Track - Pull the tip from 20kOhm to ~600 Ohm

Hallo,
I have in my car VWCDPIC working with my android HTC desire phone, but now without remote control of this phone. For me is enough implement jump between tags and play/stop function - so the same functions which I have on headset for my phone.

I checked firmware which is here :
http://www.k9spud.com/vwcdpic/devel/vwcdpic3/flash/

and checked source code. I found inside source code this information :

; VWCDPIC Volkswagen CMR PIC16F627(a)/PIC16F628(a) Connections
;--------------------------------------------------------------------------
; PIC RA3 -> VW Pin 2 Clock to Head Unit
; PIC RA2 -> VW Pin 1 Data to Head Unit
; PIC RB0 <- VW Pin 4 Data from Head Unit
; Make sure PIC and VW Head Unit have common GND.
;
; PIC RB6 -> PJRC MP3 Player RX (19.2Kbps serial)
; PIC RB7 -> Archos Jukebox RX (9600bps serial with weak pull-up)
; Make sure PIC and MP3 Player have common GND.
;
; Volkswagen CMR:
; PIC RB1 -> TP11 when button Mix is pressed has about 15
; seconds logic low output (one pulse)
; ALSO:
; when soft-button CD6 is pressed, TP11 has
; about 3 seconds logic low output (one pulse)
; FINALLY:
; when button SCAN is pressed, TP11 has about 20ms
; logic low output (one pulse)
;
; PIC RB2 -> TP14 when button Next Track (>>) is pressed, has
; about 20ms logic low output (one pulse)
;
; PIC RB3 -> TP15 when button Last Track (<<) is pressed, TP15
; has about 20ms logic low output (one pulse)
;
; PIC RB4 -> Track number is incremented when one pulse (low active) on RB4
;
; PIC RB5 -> Track number is decremented when one pulse (low active) on RB5

Important information is that on RB2 and RB3 is pulse after next/last track pressing. But it's for PIC16F627 with 16pins.
What I need is modify this firmware for PIC12F629 which is now connected :

; VWCDPIC 3.x PIC12F629/PIC12F675/PIC12F683 Connections
;--------------------------------------------------------------------------
; PIC GP0 -> VW Pin 2 Clock to Head Unit
; PIC GP1 -> VW Pin 1 Data to Head Unit
; PIC GP2 <- VW Pin 4 Data from Head Unit
; Make sure PIC and VW Head Unit have common GND.
;
; PIC GP4 -> PJRC MP3 Player RX (19.2Kbps serial)
; PIC GP5 -> Archos Jukebox RX (9600bps serial with weak pull-up)
; Make sure PIC and MP3 Player have common GND.

so I want cancel GP4 and GP5 - I don't need this serial communication and on GP3, GP4, GP5 I need next/last track pulse and play/stop pulse.

Is there somebody who is able change program and implement it ?

Thanks

Alda

You guys inspired me to look deeper into this. I found a few potential solutions. I am not one to really spend a lot of money on this type of stuff, but there is one heck of a solutions commercially available:

(can't post a link, but lookup Scosche BT1200)

If you click on the download link and look at the instructions, you can really see how this thing works. It is a pretty elegant solution, but then again you pay for it as well. I like that it allows BT streaming or direct connect.

It seems to me that the whole reason this stuff is so hard to find is due to Apple's longtime patent of a way of controlling portable audio devices. I am not sure what the specifics are, but you certainly don't see anyone making a nice adapter/connector from iPod to TRRS that codes these commands for TRRS signaling. My fiance has a car with play/pause, volume controls on the steering wheel, and I would love to have it all work with a generic mp3 player, but unfortunately it is set to work with an iPod, and there doesn't seem to be any other way about it. It is almost like consumers are being bullied by these patents. I want the functionality, but I am not going to be stuck with buying from that brand.

I think that best way is firmware modification as posted futaris , but I don't have enough skills to do that. Or is some modificaton for HTC phones ( and not only HTC - it's only about resistance ) available now ?

Alda