Modern cars go to great lengths to incorporate new technologies and optimize the user experience, but sometimes they miss small details. For example, Sami Pietikäinen's car supports hands-free calling via Bluetooth but not audio streaming. His solution? Build a Bluetooth DAC based on the Raspberry Pi Zero W and connect it to the aux input of his stereo, so he can listen to all his music through it.
Our love-hate relationship with Bluetooth technology is far from over. Eliminating cables, compatibility, and greater independence clash with signal problems, limits on its range, and implementations that leave much to be desired. However, there is a certain appreciation for it in the DIY space, as it can solve several problems with the right hardware.
One of those problems was experienced by Sami Pietikäinen of the Page Fault Blog. His car has Bluetooth support, but only goes as far as hands-free mode. In other words, any plan to transfer audio from his smartphone to the stereo wirelessly will require additional components... and that's where the Raspberry Pi Zero W comes in.
Hardware
As we already know well, the Raspberry Pi Zero W includes WiFi and Bluetooth. The first step is to get a pHAT DAC, which costs less than 15 euros and noticeably improves the Raspberry Pi's audio. In general, modules or 'hats' connect on top of the Raspberry Pi, but Pietikäinen decided to solder the GPIO underneath to reduce the size. The rest is a matter of connecting the DAC to the stereo's aux input.
Software
If the hardware part doesn't seem complicated, you're right. Pietikäinen's real hack lies in the software. Instead of adopting a standard Raspbian image, he decided to customize to the maximum (or even gut) the Linux distro using Yocto, leaving only the bare minimum for the Zero W to function as a Bluetooth DAC.
Ready to use
Yocto is not a tool aimed at beginners, and Pietikäinen acknowledges this by offering a ready-to-use image for any Raspberry Pi Zero W. If you were looking for a project for this upcoming weekend, I think you've found it.
Official site: Click here
