Very good points about monitoring your cat's inputs and outputs. My cat develops urinary tract issues about once a year and you notice the reduced appetite and litter box use. I have a Litter Robot so I do make sure to check it at least once a day. The litter box is another thing I'd like to throw an ESP2866 in so I can monitor litter box use frequency.

Any ideas on how to detect a poop versus a piss? Perhaps there are urea sensors? The mass of the litter clump would be another good data point to measure, but I don't have any ideas about how to set it up with the Robot.

This hacker has the right idea:

https://twitter.com/litterboxtweets