The plan was to utilise ESP32 hardware with the Espressif HFP stack to do all the Bluetooth heavy lifting. [Jouke] did find out the hard way that this is not a commonly-trodden path in hackerland ...

He had a set of Nokia Bluetooth headphones that he was willing to part with, so he disassembled them to see how he might interface with his car stereo. Connecting the headset to his head unit was ...

But if you'd prefer to keep one ear open and go a little old school, Bluetooth headsets are still out there. Less bulky for some people, with a focus on delivering a great hands-free phone call ...