Korean rice cooker: when the rice is ready, the voice says “Delicious rice is ready to be served” and the lid automatically opens. Based on time/water level one sets, the rice cooker serves the most ideal type of rice.
Theft alarm in stores: When people walk out with a product without paying, the alarm detects it and makes a loud noise.
Automatic Cat feeder at my house: whenever it is user’s set time, the voice recording of me saying “time to eat kitties!”(which I trained my cats to come and eat when I say this) plays automatically, and the chamber inside the feeder rotates and sends out cat food.
Not related to this topic, but I also made something similar in my last semester’s class, which is an automatic feeder that detects cats movement and also a cat exerciser.