Programmable record changer

A programmable phonograph record changer providing automatic sound track selection from a plurality of recordings, each recording having a plurality of sound track bands spaced apart from one another by a plurality of intraband land areas, comprising:

• an electro-optic scanner;
• land sensing means connected to said electro-optic sensor including means for developing a threshold signal which varies as a function of surface reflectivity to provide an output signal as said scanner detects an intraband land area;
• tone arm lift means for raising the tone arm to a predetermined elevated position with respect to any of said pluraity of records on the record changer;
• tone arm sweep means for moving the tone arm in a plane generally parallel with the record surface to permit the scanner to detect the intraband land areas;
• and
• a control means responsive to the output signal developed by said land sensing means and including a programmable memory for actuating the tone arm lift and sweep means to position the stylus on any one of the plurality of records to play a preselected sound track band as dictated by said memory.

A programmable phonograph record changer providing automatic sound track selection from each of a plurality of recordings, each recording having a plurality of sound track bands spaced apart from one another by a plurality of intraband land areas, comprising:

• an electro-optic scanner including a light emitting diode and a phototransistor mounted on the phonograph tone arm so that the light emanating from the light emitting diode is reflected from the surface of a record to the phototransistor;
• land sensing means connected to said electro-optic scanner including an automatically adaptive threshold means for developing a variable threshold which indicates the presence of an intraband land area below said scanner and for providing an output signal as said scanner detects the intraband land area;
• tone arm lift means mounted on the end of the tone arm in proximity to the electro-optic scanner for raising the tone arm to a predetermined elevated position with respect to any of said plurality of records on the record changer;
• tone arm sweep means including a generally vertical rotatable shaft mounting said tone arm for rotation in a generally horizontal plane and drive means engageable with said tone arm shaft for driving the tone arm across the record surface in a plane generally parallel therewith to permit the scanner to detect the intraband land areas;
• and
• a control logic means responsive to the output signal developed by said land sensing means and including a keyboard and a programmable memory for storing the preselected sound track selections to be played and for actuating the tone arm lift means and the tone arm sweep means to position the stylus on any one of said plurality of records at the beginning of a preselected sound track band as dictated by said memory.

A band selector providing automatic band selection from a recording having a pluraity of recorded bands spaced apart by a plurality of unrecorded land areas, comprising:

• transducer means positionable with respect to said recording;
• an electro-optic scanner;
• and
• land sensing means connected to said electro-optic scanner comprising an automatically adaptive threshold means for developing a variable threshold as a function of overall surface reflectivity which indicates the presence of an unrecorded land area adjacent the transducer means and for providing an output signal as said transducer means encounters an unrecorded land area.

A programmable record changer providing automatic sound track selection from a plurality of recordings, each having a plurality of sound track bands spaced apart from one another by a plurality of land areas, comprising:

• an electro-optic scanner including a source of radiation and a detector for radiation emitted by said source and reflected from the surface of a record;
• land sensing means connected to said detector and including means for developing a threshold signal which varies with the surface reflectivity characteristics of a record and means controlled in part by said threshold developing means for detecting the presence of a land area below the stylus by providing an output signal as the stylus encounters said land area;
• tone arm lift means mounted on the free end of the tone arm for raising the tone arm to a predetermined elevated position with respect to any of said plurality of records on the record changer;
• tone arm sweep means for moving the tone arm in a plane generally parallel to the record surface to permit the scanner to detect the land areas;
• and
• programmable means for storing a predetermined selection of sound track bands to be played and positioning the stylus on the record under the control of said output signal to play said preselected sound track bands.