TL;DR What options are there for controlling an android device apart from the screen if you don't have access to the physical buttons? Can you remap bluetooth keyboard inputs to different functions? Details below. I'm currently in the planning stages of installing a Galaxy Tablet in my car to work as a headunit. Watching videos and researching it I found it was possible to use steering wheel controls with android to control volume and playlist. My car however does not have steering wheel controls. I don't really want to be messing with volume and brightness while I'm driving, so I'm looking to hack something together. The options I'm looking for are: Volume+, Volume-, Play, Pause, Next, Back (I've found controllers with these buttons already built in) Brightness+, Brightness-, Power One thought that I had was to find some sort of Bluetooth controller, and I've found quite a few with the first set but none with brightness and power control. Can you somehow remap keys to control these things? One other question before I go, I'll be using RTL-SDR for this project, which requires USB. I'll be using an OTG cable for this. My question is if an option to do what I want to do with the controls exist in USB, can android support more than 2 inputs through USB. (i.e. Power, RTL-SDR, keyboard)?