Maker David Hunt created a clever hack for a door for dog owners who are tired of getting up to let Fido outside at every whim. The system is called Pi-Rex, a bark-activated (note, not voice activated, but bark activated) door.
Hunt states, "Sleep deprivation has been driving me mad recently. And it’s all down to a new member of the family (kind of), our new dog. She barks at night when she’s left out. She barks early in the morning when she’s left in. So once I recognized the patterns of her barking, I realized that all I needed was something that would let her out when she needed to go for a pee, usually around 6:30 in the morning. I could do this with a timer switch and a door strike, but where’s the fun in that."
No fun at all, compared with this:
The giggles and the "God Almighty" upon the door's opening at a bark are hysterical enough to make the project worthwhile, regardless of if his dog actually uses the door.
I live in an apartment, and have a dog that barks all the time anyway, so sadly I can't really test this one out. The closest I've gotten is training him to do the old pull-the-rope-to-open-the-door trick. But I find it brilliant nonetheless, and the moment I move to a place with a back yard, this project is on the to-do list.
Here is more about the Pi-Rex project, including parts and code details.