C2 owner here, and an ADHD sufferer as well. I've always utterly hated working out throughout my life as sitting on a machine or out running without a goal other than "work out to maintain health" bores me out of my mind. I keep it bearable right now by catching up on TV (the little bit of time I have to actually watch anything these days), but gamification I think would get me even more into it.

I'd probably be interested in this product if it were able to be tied into my machine. That said, I don't think I'd actually be interested in the part that seems to be your impetus to make your own hardware platform (the variable resistance/strength training).

I primarily use my machine for cardio, and to keep weight off, and to that end I do indeed follow an interval training approach. However, I don't play with the resistance. I simply increase my strokes per minute for certain intervals throughout the workout. I think its a bit too much of a sacrifice to throw out the quality and results of a proven platform just to implement that one set of functionality (which I personally would probably not even use).

I'd rather see the capital raised put into making the software and user experience the best it possibly could be rather than being split between the software and an actual rowing machine.