My motorcycle has a Bluetooth instrument cluster. It pairs with the manufacturer's phone app and shows turn-by-turn navigation right on the dash, which sounds great until you actually use it. The nav is routed through a maps provider I don't love, the app is clunky, and there's no way to extend any of it.
I kept thinking: it's just my bike talking to my phone over Bluetooth. How locked down can it really be? So one weekend I decided to find out, and a few weeks later I had Google Maps navigation running on the cluster through an app I wrote myself.
Here's how that went.
There are no docs
Of course there aren't. It's a proprietary protocol, and the only reference that exists is the manufacturer's own app, in compiled form. So step one was just watching.
