I have five great cats and often work late or am out of town, so am trying to potty train them. I have been pretty successful right off with two of them using a toilet training kit and am now working on the other three. As with everything cats, they tend to watch the others and learn even more quickly. However, as this potty training project has progressed, it has quickly become apparent that while the cats can learn to use the toilet well enough, they can't ever actually flush it . . . duh!
So after some further research, I found this great automatic toilet flusher called the FlushMinder. It is designed for human use, but with a little ingenuity, I simply mounted the sensor on the open toilet lid so it would detect the cats and viola . . . automatic flushing!
I was worried that it might actually scare away the cats, but the motor on it flushes the toilet slowly and quietly so they don't run off prematurely. In fact, several of them come back to watch and listen to the whole flush thing, so guess they like it too. Not sure I can post the link for it here, but just search the "FlushMinder" on Amazon or at Water Saver Products, LLC and you will find it. Let me know how it works for you and if you have any tips or ideas.
Now I do monitor their "output" periodically with the litter box as others have noted. When I need to do that, I just put the litter box beside the toilet and close the lid so they can't use the toilet. As we know, cats are pretty tolerant of have the litter box moved around and find it easily. My toilet trained cats will go back and forth without problem and it sure is nice to have the toilet as an option most of the time because it saves a lot of cost on litter and is much less hassle . . . Judy