Abstract: A device for monitoring a shaft coupling coupling a first shaft to a second shaft includes an optical unit having a receiving element to receive electromagnetic radiation. A modifying unit modifies a radiant energy impinging on the receiving element as the first shaft runs asynchronously with respect to the second shaft. The modifying unit includes a holographic optical component designed for arrangement on and/or within the first shaft, and a diaphragm designed for arrangement on and/or within the second shaft and including radially arranged slots and radially arranged filled regions in an at least substantially regular sequence. The diaphragm includes an at least substantially centrally arranged opening. The holographic optical component is designed for illumination or irradiation with the electromagnetic radiation and generates a pattern having radially arranged areas with a first radiant energy and radially arranged areas with a second radiant energy in an at least substantially regular sequence.

Abstract: An air mass sensor has a three-part configuration formed of an insertion element, a measuring channel element and a housing element for accommodating an evaluation device. In order to be able to provide flexible insertion elements for a device having a short overall height, the measuring channel element and the housing element are joined to one another along a side of the measuring channel element that is perpendicular to the main direction.