It doesn't work when you are completely off, at least not at this stage. But if using it at better times of the day are reorganizing things, that might be enough.

I'm working on something else that I'll go ahead and put in the public domain. I am going to use a "tilt sensor" made from a soda straw with a BB inside and a pair of contacts at one end. BB rolls to one end, switch closes. Back the other way, switch opens. Glue the straw to a big safety pin.

Make a pair of those, stop by Radio Shack for a low cost buzzer and battery box. Pin one sensor to each leg to train to lift that blasted knee higher. Cost $10.

<Also has some cool possibilities running through game port on my desktop computer >