Sweet Input Display is a .NET program written in C# and WPF using Visual Studio 2013. It interfaces with a virtual COM port, where the inputs from a NES controller are captured so that they may be displayed on stream. Using a Teensy arduino and a spliced controller cable, inputs are split between the NES and a USB cable connected to my PC, sent to a COM port, and read in by the .NET application to be rendered on a WPF canvas.
Stream with Sweet Input Display in action: Battle Kid in 42:51
Todo: Embed stream, release source code