XS3868 bluetooth module

[trotski94]

Hello everyone, I love messing around with electronics but until now all I've ever really done anything from scratch i've always picked up pre-made projects and used an Arduino and some simple wiring to achieve what i want (like RC helis to auto drones and the like..)

Anyway, i just bought a Vauxhall(opel) insignia, got a quote for a retro-fitted Bluetooth solution and it came back at £300, so i though f**k that ill give it a shot myself.
So here's what i had planned, i bought myself a XS3868 Bluetooth module because apparently it supports the HSP, A2DP & AVRCP Bluetooth profiles which should be spot on for what i need. I plan to get into the back of the head unit on the car and find out where the signals from the steering wheel controls go and attempt to splice onto them, ill then extend these back to the center arm rest where a 12v cigarette lighter socket, a USB socket and a 3.5mm auxiliary jack sits, should be perfect for powering the device and getting the sound into the stereo through the AUX.

There's a couple of issues I've read into online that might slow me down in doing this, first being it appears the XS3868 doesn't remember synced devices when it switches off (sources for this aren't brill, hopefully someone can tell me otherwise) so i need some way of providing it power when the ignition for the car is off, i'm thinking maybe a small rechargeable battery? (this leads into i have no idea how to handle charging a battery but its all a learning experience right..)

The second issue is only power supply's i have to hand are a 5v supply and a 12v supply, and the XS3868 seems to like a 3.7v supply, i've only ever bought adjustable buck converters to achieve this sort of thing and I'm wondering if there's a cheaper/easier - whilst not being too inefficient - way of regulating voltage.

I'm tempted to stick an Arduino in the works somewhere too, mostly because later down the line i want my internal lights to dim themselves when ambient light get below a certain threshold which i imagine shouldn't be hard to do using the feedback on power from one of the LEDs inside the dash to see how dim it already is, and sending power into the toggle switch that controls it to increase/decrease the light output based on the already set dimmer value and either a light sensor somewhere in the car or somehow break into the cars light sensor, not something I'm entirely sure i can do.

Anywho i dont really want this to sound like a "show me how to do the thing" thread, i think that's how it sounds but im looking mostly for guidance on my first real project.

[Neverther]

Slap one of these in there. No steeringwheelcontrols but meh.
I would get the circuit diagram before anything as in worst case the steeringwheelcontrols could be tied to the instrument cluster and communicate via CAN to the radio (I think atleast nissan does this as the dash display menus are controlled with the wheel).
Maybe a CAN sniffer to see if the wheel buttons are on CAN line? Then just connect micro with CAN to read the buttons and control the player?


I attached mine to the CD changer line (old car) so it can receive some command from the headunit (and therefore from the steeringwheel controls). Little micro sits on the databus emulating cd changer and controls the player with software buttons.
The cd changer emulator could be bought but theyre expensive (60 eur for Yatour and they dont have bluetooth).