Abstract: A small self-contained unit is provided to indicate rotation of a machine element such as a brush in a domestic vacuum cleaner. The rotation indicating device may be mounted inside the nozzle of the vacuum cleaner so that through an aperture in the vacuum cleaner nozzle, an indicator lamp may be observed, and it will be illuminated upon rotation of the vacuum cleaner brush. The rotation indicating device includes a housing which carries the lamp in a fixed longitudinal position on the housing, which accommodates a wire coil within the housing and the coil cooperates with a rotating magnet on the rotating brush. All of the parts are fixed in longitudinal position so that when the indicating device is mounted in the vacuum cleaner, the wire coil is in position to cooperate with the magnet and the lamp is in position adjacent the vacuum cleaner nozzle aperture.