SINGLE WAVELENGTH LIGHT SOURCE FOR USE IN LIGHT BASED POSITIONING SYSTEM
In one aspect, the present disclosure relates to a self identifying single wavelength light source including an emitter that produces a single wavelength of visible light; and an autonomous modulator in electrical communication with the emitter that automatically and continually modulates the single wavelength of visible light produced by the emitter, wherein the modulated single wavelength of visible light represents an identification code of the light source. In some embodiments, the emitter is a light emitting diode (LED) and further includes an LED driver that provides a specified voltage and current to each LED in the light source. In some embodiments, the emitter can be a blue light emitting diode (LED).
1 . An asynchronous self-identifying single wavelength light source comprising:
an emitter that produces a single wavelength of visible light; and
an autonomous modulator in electrical communication with the emitter that automatically and continually modulates the single wavelength of visible light produced by the emitter to form a modulated signal,
wherein the modulated signal represents an identifier of the light source capable of being demodulated,
and wherein the modulator comprises a nonvolatile memory storage area that stores the identifier of the single wavelength light source, wherein the nonvolatile memory comprises instructions to generate a random identifier for the single wavelength light source when the single wavelength light source is powered on.
2 . The single wavelength light source of claim 1 , wherein the emitter comprises a light emitting diode (LED) and further comprises an LED driver that provides a specified voltage and current to each LED in the light source.
3 . The single wavelength light source of claim 1 , wherein the emitter comprises a blue light emitting diode (LED).
4 . The single wavelength light source of claim 1 , wherein the modulator comprises solid state transistors that are digitally controlled by a microcontroller and the solid state transistors change the current provided to the emitter and as a result switches the emitter on and off.
5 . (canceled)
6 . (canceled)
7 . The single wavelength light source of claim 4 , wherein the microcontroller comprises a timer module to generate a sequence of signals that control the modulator to send a modulated light signal through the emitter that includes the identifier.
8 . The single wavelength light source of claim 7 , wherein the modulated light signal comprises a starting bit sequence to indicate the beginning of a packet of information followed by the identifier.
9 . The single wavelength light source of claim 7 , wherein the modulated light signal comprises an error detection identifier after the identifier.
10 . The single wavelength light source of claim 7 , wherein the modulated light signal comprises a pulse width modulated signal where a frequency of the modulation corresponds to a symbol of digital data.
11 . The single wavelength light source of claim 7 , wherein the modulated light signal is on off keyed to transmit the identifier of the single wavelength light source.
12 . The single wavelength light source of claim 1 , wherein the identifier of the single wavelength light source comprises location information that provides an indication of the geographical location of the single wavelength light source.
13 . An autonomous modulator that controls modulation of a single wavelength of visible light produced by an asynchronous single wavelength light source to send an identifier that identifies the single wavelength light source, the modulator comprising:
memory that includes an identifier for the single wavelength light source, the identifier being represented by a predetermined sequence of signals, and instructions to generate a random identifier for the single wavelength light source when the modulator is powered on; and
an electrical connection to an emitter of the single wavelength light source that automatically and continually sends the predetermined sequence of signals to the emitter to modulate the single wavelength visible light produced by the emitter according to the predetermined sequence of signals.
14 . (canceled)
15 . The modulator of claim 13 , wherein the predetermined sequence of signals comprises a starting bit sequence to indicate the beginning of a packet of information followed the identifier after the starting bit sequence.
16 . The modulator of claim 15 , wherein the predetermined sequence of signals comprises an error detection identifier after the identifier in the packet.
17 . The modulator of claim 16 , wherein the predetermined sequence of signals comprises a pulse width modulated signal where a frequency of the modulation corresponds to a symbol of digital data.
18 . The modulator of claim 13 , wherein the predetermined sequence of signals is on off keyed to transmit the identifier of the light source.
19 . The modulator of claim 13 , wherein the identifier of the single wavelength light source comprises location information that provides an indication of the geographical location of the single wavelength light source.
20 . The modulator of claim 13 , wherein the single wavelength light source comprises a blue light emitting diode (LED).