Abstract: A device for detecting a condition at a plate or a wall of a domestic appliance, in particular a kitchen appliance, simplifies and improves condition detection. A sound wave transmitter disposed at least at one first location of the plate or the wall transmits sound waves onto the plate or the wall. A sound wave receiver or a sound wave-reflecting element is disposed at a second location of the plate or the wall remote from the sound wave transmitter. At least one parameter of the sound waves is influenced by a condition prevailing between the first location and the second location. An evaluation circuit evaluates the condition-governed influencing of the sound waves.