Hey! I wanted to share my custom head unit project that I built for my old BMW. It has been installed in my car for almost two months now and it's been working great so far.

My build is based on Raspberry Pi 5 with NVMe drive. As a software I use Hudiy app and Raspberry Pi Bookworm OS. NVMe drive gives it a super fast boot time (around 12 seconds). Hudiy app and Android Auto also run very smoothly.

The priority in this project was the display. I'd tried a few aftermarket head units before but they just didn't cut it. The screens on those units were unreadable in sunlight due to reflections. I found a perfect 10.3" Full HD screen with an anti-glare surface. It's spot-on for what I need - sharp image, no blinding backlight at night and it stays perfectly visible even on sunny days. The screen bezel comes from my old Android head unit.

In the project I used a 5.1 sound card so I have full control over balance, fade and the subwoofer. The sound card is connected to an Audio System CO-40.4 amplifier (for the speakers) and an Audio System M-330.1 amplifier (for the subwoofer). The amplifiers are turned on and off via a GPIO pin on the Raspberry Pi and a relay connected to the REMOTE wire.

The Raspberry Pi is powered by a 12V->5V 5A DC converter. I don't use any safe shutdown system. The power is simply cut off when the key is removed and so far everything has been working perfectly. I turn the head unit on and off several times a day without any issues.

I'm currently working on displaying vehicle data from the IBUS since my car only supports a limited range of OBD data due to its age.