> I have an easier solution - weigh the cat on a pressure pad just before the flap - allow for variances of a few ounces but not much more. A mouse weighs arou

> I have an easier solution - weigh the cat on a pressure pad just before the flap - allow for variances of a few ounces but not much more. A mouse weighs around 20 grams, or 0.7 ounces. That's about 0.5% of the weight of a cat.