Gavin Costigan
Posts: 1
Joined: Thu May 06, 2021 12:43 pm

Android Apple Carplay Project on Kenwood Head unit keeps crashing. Ive tried everything.

Thu May 06, 2021 12:46 pm

For the last few weeks now, I have been working on getting Apple Carplay on my Kenwood DNX772BH aftermarket head unit from 2014. Kenwood has an old feature that allows you to mirror and control your android device using the head unit's touchscreen. It works over hdmi and bluetooth and the Kenwood Smartphone Control app on the playstore.

So I loaded up lineage 16(Android 9) on the rpi 3b and connected one of those carlinkit usb carplay adapters for android car stereos. And believe it or not... It works! I can control the pi's os through the touch display on the Kenwood, and carplay is streamed from the rpi to the display. And it works surprisingly well, except for the one issue I'm having that I absolutely cannot explain.

The issue is as follows... When just sitting in the car, everything works fine. I sat in my driveway for an hour messing with it with no problems. The problem started when I started driving. after 5 or so minutes, the pi would completely crash and reboot. It triggers a cycle of endless bootlooping until i unplug it and try again later. (It will continue to bootloop if I plug it in immediately after.) However If I run just the carplay software and only mirror my display without using the Kenwood app, it seems fine as far as I can tell. I haven't done any extensive testing on that.

Things I've Tried...

- Power source - I know the pi is picky about power and doesn't like it to fluctuate. I know my car's alternator is really bad at providing stable power, so I have tried, 4 amp usb cigarette chargers, battery bank, and a 12v to 120v inverter with a 5.2v 2 amp usb power brick plugged into it. None of which made any difference.

-Different versions of android(lineage 14.1, 15.1, 16, and 17)

-Different Pi's (3b and 3b+)

-Different SD cards

-Different power cables

-Different methods of cooling - I used one of those aluminum body cases from Flirc with the conductor that goes over the cpu(yes I had the thermal pad installed) on the 3b. The 3b+ had no cooling at all. Made no difference. And the pi is in a semi-ventilated area. Not in front of the ac or anything but sitting ontop of the center console.


Suspicions...

- Cooling still - The aluminum case was pretty hot to the touch. It didn't seem like anything the pi couldn't handle, but it was pretty warm considering the inside was probably much hotter.

-The Kenwood App - If this is the issue I will be surprised. No one has reported this issue using the app. Then again. I doubt anyone else has ever tried to use this with a raspberry pi.

-The raspberry pi just not being good enough - I'd like to get my hands on a pi 4 this weekend because its faster, and I'd probably use it if this project failed anyway. I doubt that the pi4's increase in performance will make a difference. I honestly would be more interested in being able to try android 11 on it to see if that works.


Final thoughts...

I am open and begging for any possible suggestions. I know I am definitely the only person on earth to do this, and it is killing me. I have spent the past couple of weeks troubleshooting. I think my next try will be a pi4 with a massive heatsink and active cooling. Also I can take some pictures or video of it working tomorrow if anyone is interested.

Last thing - Should I just get the two gb model, or spring for the 4 or 8? I really dont like the idea of spending that much on a pi tho.

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