I'm developing a software that will be preinstalled in a headless PC. The user will see the "output" of the software processing (sent with a given protocol via ethernet), and can configure some parameters of the running app via web interface.
The application have some proprietary processing code, uses some third party library (closed, precompiled libraries under BDS license to use third party hardware) and some LGPL libraries linked dinamically. To display/stream the mentioned web interface we would like to use a GPLv3 library.
How will this affect the rest of the software licensing?
I've read several topics on this, and one quite similar here. The main difference in my opinion is the fact that the poster is releasing a virtual machine image, that the user can install and use on his PC, while we are actually giving the user a "black box".
The linked thread mentions the AGPL license, that in our case will probably put all the software under AGPL. But looks like the GPL won't do it, if I got it right. Or better, the GPL says that a software running on a server will not be affected by the license (right?). This seems to be actually the case. But we don't really have a server running the app, say, in our office, and the users are connecting to it; we are actually selling such server, that the users will have on their office (actually on their machinery), although they cannot do anything with it besides access the web interface and collect outputs.
I'll try to give you the big picture with a little simplfied example.
I have an overtechnological thermostat. It's a device that runs Ubuntu Server. My app is running on it. It uses a third part library to access the thermal sensor and gather data. It does it sophisticated calc with my proprietary algorithm and controls the water eater. It displays the outputs and controls on a web interface for the user (no other way to access the system for the user); the interface display/streaming is done using a GPLv3 library. What licensing can be used for my software, in particular my algorithms? And what about third party closed libraries used?