After years of thinking "how could it be done"... and sundry threads here!... I have finally Got It (partly) Out The Door.
I have a working prototype.
A simple (inexpensive) PCB into which you plug an Arduino Pro Mini (again... inexpensive... I said this was for schools, and homes just dipping toe in the Arduino water)
"Out of the box", it gives the novice two buttons to play with, and four LEDs. Learning to hook things up can come (not too much) later.
Then what can be done is expanded by plugging simple daughter boards into NoviceGuard.
Explained at....
So, Gentle Reader, what do I want from you?
Thoughts! Can you see how a kid could mess up Arduino or NoviceGuard, without deliberate malice?
The greatest weakness, I think, is that the users will have to understand and respect "Thou Shalt Not Change the PinMode lines in setup()"
But maybe you can see other weaknesses?
I have a few NoviceGuards I will loan to anyone who can convince me that they will actually, quite quickly, evaluate and report back on (and return) the device. Details in the page cited. (Please do not waste other forum readers time with starting "I'd like to borrow one" discussions here, in the thread.)
Ideas for good daughter boards, and programming challenges for novices with a NoviceGuard welcome! By email. Or here in the thread!
Thanks... I hope this product will make it possible to bring Arduinos to a wider audience... including the kids of Arduino enthusiasts who also happen to be parents.