Device and System for Measuring Flicker

Abstract

Techniques are disclosed for measuring an amount of flicker produced by a light source. In one embodiment, a flicker measuring device includes a photo sensor to measure the amount of light produced by the light source, a dedicated processor to receive and process data from the photo sensor, a memory bus coupled to an analog-to-digital converter (ADC) and to a first memory, and a direct memory access (DMA) bus coupled to the ADC and to a second memory. In another embodiment, a flicker measuring system uses a light sensor, an associated circuit and a portable computing device (PCD), such as a smart phone, to measure an amount of flicker produced by a light source by sending an electrical signal from the light source and associated circuit via an audio output to an audio sub-system of the PCD, so that the PCD may calculate the flicker value.

What is claimed is: 
     
         1 . A device for measuring flicker produced by a light source, the device comprising:
 a light sensor configured to transform collected light into an electrical current signal;   a circuit coupled to the light sensor, the circuit configured to convert the electrical current signal into a voltage signal; and   an audio output coupled to the circuit, the audio output configured to interface with an audio input of a portable computing device and to transmit the voltage signal via the audio output to an audio sub-system of the portable computing device coupled to the audio input.   
     
     
         2 . The device of  claim 1 , wherein the light sensor and the circuit are disposed on a same printed circuit board. 
     
     
         3 . The device of  claim 1 , wherein the light sensor is a three-color light sensor having three channels that each have a responsivity different from the other two channels, and the three-color light sensor is configured to generate three electric current signals. 
     
     
         4 . The device of  claim 3 , wherein the circuit comprises a three-channel amplifier configured to convert each of the three electric current signals into three voltage signals, and wherein each channel of the three-channel amplifier utilizes a controller variable resistor. 
     
     
         5 . The device of  claim 1 , wherein the circuit comprises:
 an amplifier configured to convert the electrical current signal into the voltage signal;   a low-pass filter configured to filter out undesirable higher frequencies from the voltage signal; and   a voltage limiter configured to limit an amount of voltage output to the audio subsystem from the voltage signal by the audio output of the device.   
     
     
         6 . The device of  claim 5 , wherein the amplifier has a bandwidth that matches a bandwidth of the audio sub-system of the portable computing device. 
     
     
         7 . The device of  claim 5 , wherein the circuit further comprises a microcontroller coupled to the low-pass filter, and wherein the low-pass filter has a variable frequency that is controlled by the microcontroller. 
     
     
         8 . The device of  claim 5 , wherein the circuit further comprises a multiplexer that determines whether the voltage signal is transmitted from the circuit as digital data or as analog data. 
     
     
         9 . The device of  claim 1 , wherein the device is configured to draw power from a universal serial bus (USB) port of the portable computing device and transmit the voltage signal via the audio output. 
     
     
         10 . The device of  claim 1 , wherein the device is configured to draw power via the audio output from the audio sub-system of the portable computing device. 
     
     
         11 . A method for measuring flicker produced by a light source, comprising:
 transforming, by a light sensor, light collected from the light source into an electrical current signal;   converting, by a circuit coupled to the light sensor, the electrical current signal into a voltage signal; and   transmitting, via an audio output jack coupled to the circuit, the voltage signal to an audio input of a portable computing device to measure the flicker of the light source.   
     
     
         12 . The method of  claim 11 , wherein transforming the light and converting the electrical current signal comprises:
 transforming, by the light sensor, the light collected from the light source into a first electrical current signal corresponding to a first color channel;   transforming, by the light sensor, the light collected from a light source into a second electrical current signal corresponding to a second color channel;   transforming, by the light sensor, the light collected from the light source into a third electrical current signal corresponding to a third color channel;   converting, by an amplifier of the circuit, the first electrical current signal into a first voltage signal;   converting, by an amplifier of the circuit, the second electrical current signal into a second voltage signal; and   converting, by the amplifier of the circuit, the third electrical current signal into a third voltage signal.   
     
     
         13 . The method of  claim 11 , further comprising adding, by an adder coupled to the amplifier, the first voltage signal, the second voltage signal and the third voltage signal into a single voltage signal that is the voltage signal transmitted to the portable computing device via the audio output. 
     
     
         14 . A system comprising:
 a device having a light sensor, a circuit, and an audio output, the device configured to generate a voltage signal representative of light collected by the light sensor and emitted by a light source, and to transmit the voltage signal via the audio output to an audio input coupled to an audio sub-system of a portable computing device; and   a software engine executable by a processor of the portable computing device, the software engine configured to:
 cause the audio sub-system of the portable computing device to sample and buffer the voltage signal received at the audio input; and 
 measure a flicker of the light source based on the sampled voltage signal. 
   
     
     
         15 . The system of  claim 14 , wherein the circuit comprises:
 an amplifier configured to convert an electrical current signal collected by the light sensor into the voltage signal;   a low-pass filter configured to filter out undesirable higher frequencies from the voltage signal; and   a voltage limiter configured to limit an amount of voltage output to the audio subsystem from the voltage signal by the audio output of the device.   
     
     
         16 . The system of  claim 14 , wherein the circuit further comprises a multiplexer that determines whether the voltage signal is transmitted from the device as digital data or as analog data. 
     
     
         17 . The system of  claim 14 , wherein the device is configured to draw power from a universal serial bus (USB) port of the portable computing device. 
     
     
         18 . The system of  claim 14 , wherein the device is configured to draw power via the audio output from the audio sub-system of the portable computing device. 
     
     
         19 . The system of  claim 14 , wherein the software engine, when executed, is configured to communicate with the light source and the device, and to modify operation of the light source and the device. 
     
     
         20 . The system of  claim 19 , wherein a user may modify operation of the light source and the device via a graphical user interface on the portable computing device.