The problem: The dog likes to bark at the door whenever a package is dropped, or whenever the neighbor walks by, or whenever she feels like barking.

The answer: A little squirt of water from a spray bottle.

The turret is made from a spray bottle filled with water. The structure is composed of 3d printed parts. A DC motor is mounted behind the bottle, and turns a pulley that is mounted to its shaft. The pulley pulls a string that is wrapped around the trigger of the bottle, and then fixed to the structure. There are two main sensors for detecting when the dog is barking at the door: First is a PIR sensor for detecting motion. And second is a sound sensor to pick up the bark. When both sensors are active, the motor is briefly activated to spray the dog (or any other noisy intruder).

The apparatus is controlled by a raspberry pi 3 which is affixed to the back of the turret with double sided tape. A flask server is running on the raspberry pi. This server handles all of the logic and IO to the motors and sensors, and provides me a way to control and monitor the turret remotely from Home Assistant.

Extra Credit:

The entire machine rests on top of a lazy susan bearing allowing it to rotate in place. A second motor has a 3d printed pinion gear on its shaft. The lazy susan bearing sits on top of a large 3d printed ring gear. By turning the pinion gear, the entire structure rotates itself.

Then I realized I had a thermal camera for raspberry pi lying around. So naturally I taped that to the front of the machine to give it heat seeking abilities.