Method and apparatus for producing a sound from a handheld enclosure

摘要

A portable electronic bar code reader having an improved mechanism for producing sounds. The mechanism includes two piezoelectric disks, each positioned in a separate Helmholtz resonator tuned to a predetermined acoustic frequency at which the piezoelectric disks resonate. The mechanism also includes electronic circuitry for exciting the two piezoelectric disks at the predetermined frequency. The Helmholtz resonators are placed within the bar code reader and drive separate sound channels that are connected to opposite laterally directed sides of the bar code reader. When the piezoelectric disks are driven in phase at the predetermined frequency, the acoustic energy emitted from the two Helmholtz resonator combines in phase in the place where the user is located.