Abstract:
An apparatus and method for converting an audio signal output through a stereo headphone jack into an infrared remote control signal. The invention utilizes the audio output to generate positive and negative pulses for operating two infrared light emitting diodes placed in parallel with opposite polarities. This allows for multiple devices with audio output jacks to be utilized as remote control devices. This connection also allows for doubling of the audio output frequency to generate infrared signals at frequencies above the normal capabilities of the audio output.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to the generation of infrared signals. More particularly, this invention pertains to the generation of infrared signals utilizing an audio signal driver. 
     Several United States Patents discuss the generation of infrared signals. These include: U.S. Pat. No. 5,268,889 entitled Display device for a compact disc player and a compact disc; U.S. Pat. No. 5,255,313 entitled Universal remote control system; U.S. Pat. No. 4,850,040 entitled Infrared remote control system for activating and deactivating one or more devices in a single enclosed space; U.S. Pat. No. 4,802,114 entitled Programmable remote control transmitter; U.S. Pat. No. 4,774,511 entitled Universal remote control unit; U.S. Pat. No. 4,769,643 entitled Transmitter driver for programmable remote control transmitter; U.S. Pat. No. 4,482,947 entitled Multi-function, multi-unit remote control system and method therefore; U.S. Pat. No. 4,371,814 entitled Infrared transmitter and control circuit; U.S. Pat. No. 4,045,777 entitled Remote control transmitter and receiver for use with a television receiver; U.S. Pat. No. 3,534,351 entitled Light coupled battery powered remote control apparatus; and U.S. Pat. No. 3,341,708 entitled Amplitude Modulated Laser Transmitter. Each of these references is hereby incorporated by reference. 
     In addition, a plethora of devices are known that produce a standard headphone output signal utilizing a stereo headphone jack. These devices include portable computers, handheld computers, midi players, mp3 players, tape players, CD players, radios, etc. . . . which will generally be referred to herein as existing audio signal generating devices. 
     These teachings fail to take advantage of the two channel audio output available from a wide variety of devices that may be used to generate an infrared control signal. What is needed, then, is an infrared generator that can generate an infrared signal from a multiple channel audio signal source. 
     SUMMARY OF THE INVENTION 
     The present invention teaches an apparatus and method for converting a multiple channel audio signal to an infrared signal. A multiple channel audio signal is an audio output typical of a stereo headphone jack that includes a ground reference with left and right channels as a first signal output and a second signal output. The present invention utilizes these signals with a first infrared generator connected from the first signal output to the second signal output so that the first infrared generator will convert a positive signal differential between the first and second outputs into an infrared signal. This gives a pulse for each positive differential. The invention then goes on to use a second infrared generator connected from the second signal output to the first signal output so that the second infrared generator will convert a negative signal differential between the first and second outputs into an infrared signal. This creates a second pulse from the waveform outputs. Thus, at least two pulses are created for each period of the signal. This allows for frequency doubling to create signals in the infrared control signal frequency range while utilizing the lower frequency capabilities of the audio output. 
     In the present embodiment, the present invention utilizes infrared light emitting diodes for the infrared generators and is connected to a standard female headphone output jack using a male stereo headphone jack that is adapted to fit the female output jack. 
     The infrared LEDs are housed in a housing encasing at least a portion of the infrared generators. The housing is constructed to define at least one opening that will allow the infrared signal to be transmitted from the infrared generators. In the present embodiment, this housing is constructed from two halves that are shown as a first case and a second case which are engaged to encase the infrared generators. The two parts of the case are held together by a a securing band wrapped around the first and second case. 
     The present invention also teaches a method of generating an infrared control signal from an audio output signal with first and second audio output signals. The method includes the action of converting a positive differential between the first and second audio output signals into a first infrared pulse, and converting a negative differential between the first and second audio output signals into a second infrared pulse. The pulses may then be utilized by combining the first and second infrared pulses to generate the infrared control signal. 
     A still further method is taught by the present invention for generating an infrared control signal. This method includes the actions of generating a first audio output signal, generating a second audio output signal, converting a positive differential between the first and second audio output signals into a first infrared pulse, and converting a negative differential between the first and second audio output signals into a second infrared pulse. These pulses may then be used by combining the first and second infrared pulses to generate the infrared control signal. 
     Each of these actions may include multiple sub actions such as the action of generating a first audio output signal including the actions of determining a first electrical audio signal for the first audio output signal; creating a first audio signal file with a first signal representation; and processing the audio signal file to generate a first electrical audio signal from the first signal representation for the first audio output signal. 
     The action of generating a second audio output signal may include the actions of determining a second electrical audio signal for the second audio output signal, adding a second signal representation to the first audio signal file, and processing the audio signal file to generate a second electrical audio signal from the second signal representation for the second audio output signal. In addition, the action of generating a first audio output signal may include storing the audio signal file. 
     Furthermore, the action of generating a first audio output signal may include reading an audio signal file, and processing the audio signal file to generate an electrical audio signal for the first audio output signal. 
     The action of generating the first audio output signal can include the action of generating a pulse at one-half of a desired infrared signal frequency as a first electrical audio signal waveform, and the action of generating the second audio output signal can comprise generating an inverted magnitude pulse at one-half of the desired infrared signal frequency as a second electrical audio signal waveform. 
     Finally, the action of combining the first and second infrared pulses may include overlapping light paths of the first and second infrared pulses. 
     Thus, the present invention teaches the advantages and objectives of generating a multiple channel audio output signal and converting this signal to an infrared control signal for use as a remote control device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic overview of an audio signal generation system and infrared converter. 
         FIG. 2  is a signal representation of a left channel waveform. 
         FIG. 3  is a signal representation of a right channel waveform. 
         FIG. 4  is a signal representation of the difference between the left and right channels using one of the channels as a reference. 
         FIG. 5  is a charted representation of the light pulse output from the converted audio signal. 
         FIG. 6  is a top elevation of the audio infrared generator of Applicant&#39;s invention. 
         FIG. 7  is a front perspective view showing the audio infrared generator of Applicant&#39;s invention. 
         FIG. 8  is a back elevation of the audio infrared generator of Applicant&#39;s invention. 
         FIG. 9  is a left side elevation of the audio infrared generator of Applicant&#39;s invention, both sides being identical. 
         FIG. 10  is a front elevation of the audio infrared generator of Applicant&#39;s invention. 
         FIG. 11  is a right side elevation of the audio infrared generator of Applicant&#39;s invention, both sides of the case being identical. 
         FIG. 12  is a bottom perspective view of the audio infrared generator of Applicant&#39;s invention. 
         FIG. 13  is a bottom elevation of the audio infrared generator of Applicant&#39;s invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a schematic overview of an audio to infrared converter  100  including a signal generation system  124  and infrared converter  110 . The signal generation system  124  can create a multiple channel audio signal  122  in any of the well known manners of the prior art. Typical frequency ranges for these prior art audio devices are in the 20 Hz to 20,000 Hz range. The present invention uses this low frequency capability to generate the high frequency infrared output signal  126  such as that typically utilized in the 37,500 Hz range. 
     The preferred embodiment generates the audio signal  122 . An audio signal file  102  is read from a storage medium such as a computer hard drive or RAM by an audio signal processor  104 . The processor  104  instructs the waveform generator  106  to create a first signal output  116  and a second signal output  118  for the left and right channels of the output  108 . The output is a male stereo headphone jack that is adapted to fit a female headphone input jack. The output  108  connects the multiple channel audio signal  122  to the infrared converter  110 . The multiple channel audio signal  122  needs to at least include a left channel output  116  and a right channel output  118  and may also include a ground reference signal  120 . The novelty of this approach is the development of the left and right channel outputs as utilized to control the frequency of the infrared output  126 . This may be understood by looking at the infrared converter  110 . 
     The infrared converter  110  includes a first infrared generator  112  connected to the first signal output  116  and the second signal output  118 . The first infrared generator  116  is an infrared light emitting diode (LED) that is adapted to convert a positive signal on the first signal output  116  into an infrared signal  126 . The infrared converter  110  also includes a second infrared generator  114  connected to the first signal output  116  and the second signal output  118 . The second infrared generator is also an infrared LED that is adapted to convert a positive signal on the second output  118  into an infrared signal  126 . In this manner, the infrared converter is connected to the first channel output  116  and second channel output  118  to monitor the signal differential between these outputs  116 ,  118 . Thus, the infrared generator  110  is adapted to convert either a positive or negative voltage differential to an infrared signal  126 . This may best be understood by referencing an example of the multiple channel audio signal  122  as shown in  FIGS. 2 through 5 . 
       FIG. 2  shows a signal representation of a left channel waveform  200  and  FIG. 3  shows a signal representation of a right channel waveform  300 . if the right channel is used as a reference point, the signal differential between the left and right channels may be seen as shown in FIG.  4 . The connection from the left to right channel provides an increased voltage by utilizing both the positive and negative aspects of the audio output signal, as well as providing a floating output. As shown in  FIG. 4 , by connecting the first LED to pulse on the positive aspect of the signal-to-signal differential, one pulse is achieved for each cycle of the signal differential. Similarly, by connecting the second LED to pulse on the negative aspect of the signal-to-signal differential, an additional pulse is achieved for each cycle of the signal differential. In this manner, two pulses are achieved for each cycle of the signal differential. This results in the pulse output as shown by FIG.  5 . Each light output pulse  500  is shown associated with either the first 112 or second  114  LED converter. 
       FIGS. 6 through 13  show various angles of the design of the audio infrared generator  100 . The infrared LEDs  112 ,  114  are housed in a housing  600  encasing at least a portion of the infrared generators  112 ,  114 . The housing  600  is constructed to define at least one opening  602  that will allow the infrared signal to be transmitted from the infrared generators  112 ,  114 . In the design shown, two openings  602  are provided with one opening  602  for each infrared generator  112 ,  114 . In the present embodiment, this housing  600  is constructed from two halves  604 ,  606  that are shown as a first case  604  and a second case  606  which are engaged to encase the infrared generators  112 ,  114 . The two parts of the case are held together by a securing band  608  wrapped around the first and second case  602 ,  604 . The securing band  608  is a colored adhesive backed band that sticks upon itself and the first and second cases  602 ,  604 . 
     Through the apparatus and waveforms of the figures, one can see that the present invention also teaches a method of generating an infrared control signal from an audio output signal. The audio output signal includes both first and second audio output signals. The method includes the action of converting a positive differential between the first and second audio output signals into a first infrared pulse, and then converting a negative differential between the first and second audio output signals into a second infrared pulse. The infrared control signal may then be created by combining the first and second infrared pulses to generate the infrared control signal. 
     Each of these actions may include multiple sub actions. For example, the action of generating a first audio output signal may include the actions of determining a first electrical audio signal that is needed for the first audio output signal. This may be done for existing remote control devices by measuring the existing signals and determining the pattern, pulses, duration and other characteristics for that signal. The process may then continue by creating a first audio signal file with a first signal representation that will generate the first electrical audio signal when the file is played. Finally, the method continues by reading and processing the audio signal file to generate a first electrical audio signal from the first signal representation for the first audio output signal. In this manner, we have created the necessary electrical audio signal that may be used for the conversion process. The action of generating a second audio output signal may also include the actions of determining a second electrical audio signal for the second audio output signal, adding a second signal representation to the first audio signal file, and processing the audio signal file to generate a second electrical audio signal from the second signal representation for the second audio output signal. This allows for both signals to be created from a common audio file. In addition, the action of generating a first audio output signal may include storing the audio signal file so that the file can be used at a later time. 
     The action of generating the first audio output signal can include the action of generating a pulse at one-half of a desired infrared signal frequency as a first electrical audio signal waveform, and the action of generating the second audio output signal can comprise generating an inverted magnitude pulse at one-half of the desired infrared signal frequency as a second electrical audio signal waveform. 
     Finally, the action of combining the first and second infrared pulses may include overlapping light paths of the first and second infrared pulses such that the signals become mixed to form the output infrared signal. 
     Thus, although there have been described particular embodiments of the present invention of a new and useful Infrared Generator from Audio Signal Source, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.