I never considered that people would be embedding my class into another class. COOL!
The reason I didn't go with a default constructor is that for the pid to run correctly, it HAS to have the things specified in the current constructor (input, output, setpoint, tuning parameters.) I figured that would be a gentle way to get people to specify them.
maybe a middle of the road option would be to include a default constructor but have it commented out? if you're writing a new class you'll likely have the know-how to find/ uncomment. if you're the standard Arduino user you'll notice no change. thoughts?
Brett