Optical traffic control system with burst mode light emitter
First Claim
1. A traffic control preemption system, comprising:
- a receiver with a photodetector and circuitry that produces a number of electrical pulses in response to each detected light pulse, wherein for each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and a threshold number of electrical pulses and an activation frequency at which the threshold number of electrical pulses is repeated activates preemption;
a light emitter;
control circuitry coupled to the light emitter and controlling the light emitter to emit bursts of light pulses, wherein each burst includes at least two light pulses and a frequency of light pulses in each burst and a frequency of the bursts cause the receiver to produce at least the threshold number of electrical pulses at the activation frequency and activate the preemption; and
a phase selector coupled to the receiver for issuing a phase request to a traffic signal controller in response to the threshold number of electrical pulses.
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Accused Products
Abstract
Various approaches for a traffic control preemption system that includes a receiver, a light emitter, and control circuitry. The receiver includes a photodetector and circuitry that produces a number of electrical pulses in response to each detected light pulse. For each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and a threshold number of electrical pulses and an activation frequency at which the threshold number of electrical pulses is repeated activates preemption. The control circuitry is coupled to the light emitter and controls the light emitter to emit bursts of light pulses. Each burst includes at least two light pulses and a frequency of light pulses in each burst and a frequency of the bursts cause the receiver to produce at least the threshold number of electrical pulses at the activation frequency and activate the preemption.
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Citations
27 Claims
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1. A traffic control preemption system, comprising:
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a receiver with a photodetector and circuitry that produces a number of electrical pulses in response to each detected light pulse, wherein for each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and a threshold number of electrical pulses and an activation frequency at which the threshold number of electrical pulses is repeated activates preemption; a light emitter; control circuitry coupled to the light emitter and controlling the light emitter to emit bursts of light pulses, wherein each burst includes at least two light pulses and a frequency of light pulses in each burst and a frequency of the bursts cause the receiver to produce at least the threshold number of electrical pulses at the activation frequency and activate the preemption; and a phase selector coupled to the receiver for issuing a phase request to a traffic signal controller in response to the threshold number of electrical pulses. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for operating a traffic control preemption system, comprising:
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activating a light emitter to initiate traffic control preemption; in response to the activating, triggering emission of a plurality of bursts of light pulses, each burst including two or more light pulses; and controlling a frequency of light pulses in each burst and a frequency of the bursts to cause receiver circuitry to produce at least a threshold number of electrical pulses at an activation frequency to activate the preemption; producing a number of electrical pulses by the receiver circuitry in response to each detected light pulse, wherein for each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and the threshold number of electrical pulses and the activation frequency at which the threshold number of electrical pulses is repeated activates preemption; and issuing a phase request to a traffic signal controller in response to the threshold number of electrical pulses. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A traffic control preemption system, comprising:
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a receiver with a photodetector and circuitry that produces a number of electrical pulses in response to each detected light pulse, wherein for each detected light pulse the number of electrical pulses represents a level of radiant power of the light pulse, and a threshold number of electrical pulses and an activation frequency at which the threshold number of electrical pulses is repeated activates preemption; a phase selector coupled to the receiver for issuing a phase request to a traffic signal controller in response to the threshold number of electrical pulses; and a light emitter, including, a power supply; a plurality of LEDs coupled to the power supply; a switch coupled to the plurality of LEDs for controllably switching power on and off to the plurality of LEDs; and a microcontroller coupled to the power supply and to the switch, wherein the microcontroller is configured to control the switch for powering on and off the plurality of LEDs to emit bursts of light pulses to activate the preemption, wherein each burst includes at least two pulses and the microcontroller controls a frequency of the light pulses in each burst and a frequency of the bursts to cause the receiver to produce at least the threshold number of electrical pulses at the activation frequency for activating the preemption. - View Dependent Claims (24, 25, 26, 27)
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Specification