[joakimsoderberg]

There is no wait, it only locks if it finds some prey. Of course there are occasional false positives. But those are very rare (haven't compiled the exact statistics for that though).

The chase thing has happened, but since the door to get in is very small other cats don't tend to follow.

Since it's really cold here in the winter I also chose to design it so that the default mode is for the door to be open. So if there's a power outage it will always be open.

Regarding the weight thing. I don't think it's feasible unless your cat always brings in rabbits or something, the weight difference is so tiny. Too many variables come into play as well, temperature differences being one, a wet cat compared to a dry one and so on. Might work, might not :)