Marantz Volume Monitor
Arduino-based volume monitor for Marantz receivers.
My Marantz receiver sits in a cabinet, which is fine, but when handling 4K content the on-screen display showing volume and input information doesn't come up. This seems to be a fairly well-known issue.
My solution to this is a small Arduino-based volume monitor that uses the Marantz HTTP API to get info about the receiver and display it on an LCD.
I used the Visual Micro Arduino integration for Visual Studio when building this so you'll see VS solution and project files in there, but you shouldn't need that to use the code.
Note I have tried to retain project structure compatibility with the standard Arduino IDE, but that's not a priority; given I use Visual Micro, I give priority to the dev environment that I work in.
This is what I used, so the pins and such are set to use these items. If you use a different set of shields or hardware, you may have to adjust accordingly.