Abstract: A device and a method for measuring a predefined characteristic of an interaction capable of being present between an interaction device and a user comprises an input interface for receiving at least one temporal sequence of data representative of the interaction and a classification module, which is connected to the input interface and processes the temporal sequence of data to output a measure of the predefined characteristic. The classification module has been configured from temporal sequences of learning data marked with the presence or absence of the characteristic. Such a measuring device may be used for detecting the start and/or end of the interaction between the user and the interaction device.