[knicholes]

I tried programming my arduino to trigger a servo to pull the handle on a spray air can when a sound over a threshold was detected by the microphone, but the servo wasn't strong enough. Enabling an outlet to an already-plugged in vacuum sounds good, though. Excellent...

I had plans to train a cat meow classifier so I wouldn't activate the can due to other noises, say a fire truck, fireworks, or a neighbor slamming a door shut.

[daniellarusso]

They actually sell these devices, but they are IR motion activated, not via sound.

https://store.petsafe.net/ssscat-spray-pet-deterrent

[Nursie]

We have one of those, they're good but the refills are strangely expensive.

Turns out they fit some standard brands of canned air, I picked up some branded "ecomoist air duster" and it works really well, although slightly quieter, it still seems to work on our kitty.