A scavenger pump seal and radial shaft seal assembly therewith are provided. Therefore, the obstacle detection device can reduce the time required for the determination to at least one-half that provided by a related art technique, and improves the accuracy of the detection of an object moving at a relatively high speed. A power converter may rectify an alternating current line signal to produce a rectified alternating current signal having peaks and valleys. A second positioning hole and a second positioning aperture may be formed on the flexible printed circuit board and the circuit board and the multifunction opening 120 may be expanded to include both the positioning holes. A first magnet is disposed on the bottom of the ornamental object.