[Nexus 7 (2013) Q&A] zandrm:
Planning a similar build

I'm headed down the path of a Nexus 7 2013 (Deb) build into a stock double-din (ish) chassis.

The car is a 2000 Audi A6, and I have a spare Symphony chassis to gut and swipe the connectors.

I have a few ideas I haven't seen here, but some of them are marque specific:

* OBD-II: Audi being, well, German, there's a K-line (Diagnostic Bus) coming into the stereo. So I'll probably build a custom STN1110+FTDI adapter, and hook that up for Torque.

* DIS: There's also what is essentially an SPI interface that talks to the LCD in the center of the gauge cluster. I'd love to figure out how to connect that to a media player to get track info to the gauge cluster. The Android environment is new to me, so I'm not sure what I'm looking for to get at this, or whether I can get Android drivers for any sort of SPI or GPIO boards. Worst case, that gets connected to some other SBC (Pi, ODroid, BeagleBone) in the chassis for various functions, and maybe I could do an HTTP POST to update from the media player.

* Steering Wheel Controls: Thinking JoyCon CPJExD to listen to the LINbus.

* Audio layer: USB DAC, and since there's no volume control for an external DAC (Behringer UCA202), using a CPJMix to take commands from the steering wheel and adjust output volume. If I get fancy with the physical installation, I'll probably reuse the Symphony's knobs to add a volume control hooked up to the ExD. (If the schematics are to be believed, I get momentary contact closures on up and down from the knob... perfect!)

* AM/FM/HD: Use the SPI and audio lines running to the trunk for the CD changer to control a Directed DMHD-1000. This keeps the RF connections to the diversity box short.

* Microphone: Thinking of just a preamp from the factory microphone to the Behringer. This will certainly provide a good mic for voice control.

Unanswered questions:

* Bluetooth: I'd love to find a way to accept audio and/or make calls from a Bluetooth phone. I'm an iPhone user (yeah, I know), and so is the GF (so, yeah, that's not changing... WAF, and it's a work phone anyway) which means TabletTalk doesn't solve the problem. I'm thinking of a Parrot device hooked up to the CPJMix, but that solution isn't fully formed yet.

* External Antennae: Has anyone torn down a Deb to see if the LTE module has a real antenna connector? From the iFixit pictures, it looks like WiFi doesn't have a real connector, and I'd assume Bluetooth shares a connector with WiFi. Those are pretty much in-car anyway, but I'd love to relocate GPS and LTE to something other that built-in antennae buried in the dash.

* Backup Camera: What works here? Open to suggestions.

* Night mode: I don't fully understand what the Faux123 color control is capable of, but I'd really like to be able to force the entire device to be monochrome, and pick which 'chrome' that is. Lux looks awesome for brightness control, but the astronomer mode is horribly misguided.

So, I guess I'm planning something a bit more ambitious than the average car install. I'm open to suggestions, wisdom of those who have Been There, Done That, and any other input. The N7 is a fantastic starting point, but I worry about the limitations of the pseudo-Open Android world.

Thanks,

-Zandr