RoboStir and StirCrazy are battery-operated devices that stand on silicone "feet" in a pot or pan. For RoboStir, claims include "stirs so you don't have to!" A StirCrazy claim: "Custards, sauces and soups can be stirred automatically." Movement depends on vibrations generated from the rotation of a weight attached to the motor. RoboStir cost us $10.99 plus $6.99 shipping and handling; StirCrazy was $4.89.
We used the devices in a flat-bottomed glass bowl, in a shallow nonstick pan with water of various depths, and while simmering a pot of thin tomato sauce, sautéing onions and garlic in a frying pan, making rice, boiling pasta, and heating cheese sauce.
We've rated each stirrer a "Don't Buy: Performance Problem." In our tests, tomato sauce burned, hot oil splattered, and cheese sauce didn't blend. The devices might spin in just one spot, stop moving as foods thicken, or if a pot isn't level, end up at the low side. They stirred fine in small pots with thin, watery food. But for foods that need stirring, a spoon and elbow grease work better.