This is really excellent work, thanks for making this available! Gives me motivation to make some of my own electronics projects available to the community :)
I would love to see more detailed technical info on the website. Stuff like, how much current can it source, and for how long? Combined with the info from Philo's Motor Tests would help to judge if the Interface C is suitable for a particular build, or if I need more than one to drive a particular creation. I suspect a large portion of the audience for this device would be able to make use of such info.