Be sure you test it so that it won't disturb the rest of the class. I can remember being in a class with a child who's watch went off, it distracted the other kids and drove the teacher nuts. Will the vibrate mode catch his attention, and hopefully not set of any sensory issues?
I think it sounds great, and is a great creative problem solver. I just hope it isn't intentionally broken, or even forbidden by some teacher/administrator with a low "beep" tolerance.
Let us know how it work, will you? I am very curious.
