To enable male patients to undergo uroﬂowmetry in a private condition without medical supervision, we devised an automatic switching and patient guidance system for the spinning disk uroﬂowmeter Urodyn 1000, using two commercial electronic devices (an infrared motion sensor tap and a memorizable vacuum ﬂuorescent display). Instead of running the uroﬂowmeter continuously, which shortens the life of the spinning disk due to mechanical wear, an infrared motion sensor turns on the devices each time a patient enters the room. The patient urinates according to the timely instructions on the visible display and voided urine directly ﬂows into a urinal. The devices are automatically turned off 5 min after the patient leaves the room. With the use of our system, men already acquainted with uroﬂowmetry could perform self-administered uroﬂowmetry any time in private. The system was considered useful for improving the quality of patient service.