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Television receiver viewing distance sensor switch

  • US 5,495,302 A
  • Filed: 05/13/1994
  • Issued: 02/27/1996
  • Est. Priority Date: 05/13/1994
  • Status: Expired due to Fees
First Claim
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1. A television receiver viewing distance sensor switch for limiting the viewer-receiver separation distance by removing a primary receiver input radio frequency signal to a television receiver when a viewer is positioned closer than a preset distance comprising:

  • a hollow housing;

    coupling means for securing the housing to the television receiver; and

    an electronic circuit within the housing having a power input and control section, an ac to dc power converter section, a sensor section, a control relay, a switch, and a delay section,the power input and control section including a wall plug extended from the housing and interconnected with a key operated on/off switch and wherein the power input and control section receives an external alternating current input,the ac to dc power converter section including a transformer with a primary coil and a secondary coil and with the primary coil interconnected in series with the wall plug and the key operated on/off switch of the power input and control section, a full wave bridge rectifier formed of four diodes interconnected with the secondary coil of the transformer, and a filter capacitor interconnected across the bridge rectifier and wherein the alternating current input from the power input and control section is converted by the ac to dc power converter section into a low voltage filtered direct current output having inconsequential ripple,the sensor section being formed of a sensor having a power input interconnected across the filter capacitor of the ac to dc power converter section and a power output for providing an electrical signal output indicative of human presence within a detection range as preset in the sensor and another electrical signal output indicative of no human presence within the detection range,the control relay being formed of an electromechanical relay having an energizing coil and a pair of associated spaced and closeable contacts and with the contacts being terminated with a pair of radio frequency signal lines that are interconnectable with an incoming television receiver signal line of the television receiver, the electromechanical relay allowing, in a first state, a substantially unattenuated passage of the primary receiver input radio frequency signal to the television receiver when the contacts are closed and prohibiting, in a second state, a passage of the primary receiver input radio frequency signal to the television receiver when the contacts are open,the switch including a NPN transistor having a base, an emitter, and a collector and with the base interconnected with the power output of the sensor for receiving the electrical signal output therefrom and the emitter interconnected between the power input of the sensor and the filter capacitor of the ac to dc power converter section, the switch also including a diode interconnected to the collector of the transistor and further interconnected between the filter capacitor of the ac to dc power converter section and the energizing coil of the control relay, and with the diode used for shunting potentially damaging transient reverse current flow when current flow through the energizing coil terminates abruptly, andthe delay section being formed of a timer interconnected between the collector of the transistor and the energizing coil of the control relay for providing a temporal delay between the appearance of the electrical signal output from the sensor as delivered through the transistor to thereby delay subsequent placement of the control relay in one of its states.

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