Abstract: A bar code reader of the type which directs a light beam to scan an area (i.e. raster scan) is disclosed herein. The reader includes first and second oscillating mirrors for directing a light beam from a photodiode to a bar code, and for directing portions of the light beam reflected from the bar code back to a photodetector which generates an electrical signal representative of the information embodied in the bar code. The first oscillating mirror scans the light parallel to a first line (e.g. vertical line) at a first frequency onto the second oscillating mirror. The second oscillating mirror scans the light from the first mirror parallel to a second line (e.g. horizontal line perpendicular to the vertical line) at a second frequency greater than the first frequency onto the bar code. The first mirror may be a compound mirror having a concave, reflective surface which circumscribes a flat, reflective surface.

Abstract: A bar code reader and the mirror oscillating system thereof are disclosed herein. The bar code reader is of the type which produces a scanning light beam by oscillating at least one mirror with a electromagnetic oscillator. The electromagnetic oscillator includes a winding which is energized with an alternating current signal produced based upon a position signal generated by a magnetic pickup. The position signal is representative of the location of the mirror. The position signal is amplified, phase-shifted, and assigned a duration based upon the difference between the desired angle of mirror oscillation and the actual angle of oscillation to produce the alternating current signal which is applied to the winding. When applied to the winding, the alternating current produces an alternating magnetic field which interacts with a permanent magnet fixed relative to the mirror to oscillate the mirror.

Abstract: A bar code reader including automatic scan beam focusing based upon decoding performance is disclosed herein. The bar code reader includes a focusing lens which is movably supported along the light path of the scanning beam. An electric motor is coupled to the lens support to move the lens relative to the light beam source in response to control signals. The control signals are produced based upon the data error rate for the data produced by the decoding circuit of the reader from the signals produced by the photodetector therein. Based upon the data error rate, the electric motor is controlled to move the lens to focus the light beam and reduce or eliminate the data error.

Abstract: An improved control system utilizing infrared communication channels for remote station control is provided. A central base controller communicates with one or more channels of sub-networks through one or more field interface controllers. Each field interface controller utilizes a dedicated base infrared transceiver for transmitting envelopes of definable duration at a preselected infrared oscillation frequency. At least one remote station receives said transmitted infrared signals at an infrared transceiver tuned to said oscillation frequency. Associated devices at the remote station decode the information from said infrared transmission or issue instructions and information to an associated input/output device. Communication over the infrared channel between the base and the remote stations utilizes a unique pulse position protocol. An initiating clear pulse begins all communications. The remote station responds to the time-location of ensuing pulses following the initiating pulse.