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  • Author Author: ajkahl
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Smarter Life Challenge: Smart Bicycle Light (update #3)

ajkahl

Light Sensing


 

 

Hi all, here's a quick demo of a photodiode coupled to one of the psoc4 internal op-amps, in turn driving PWM'd LED. I've gone for the photodiode circuit for simplicity and small component size. It's also very low on power, essentially only drawing the light current of the diode itself, it's always good to deal with active power at a low level rather than rely purely on code-side power managment. Even though the sample rate and time (DC) of the light sensor will be low, keeping it's active power low will leave open opportunities to do extra things. I may want to have a mode where the device is sampling light more rapidly to detect not only state, but transition rate of light, for example when suddenly illuminated by the headlights of a car.

 

image

 

Cheers

 

A.

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  • Great progress, Anthony!

     

    Keep in mind you have a couple Current DACs on the PSoC 4 ("IDAC") that are shared resources with the CapSense block. So, in case your design doesn't need any touch sensing, you have the option of using those IDACs for providing excitation current to your sensors where applicable.

     

    good luck!

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  • Great progress, Anthony!

     

    Keep in mind you have a couple Current DACs on the PSoC 4 ("IDAC") that are shared resources with the CapSense block. So, in case your design doesn't need any touch sensing, you have the option of using those IDACs for providing excitation current to your sensors where applicable.

     

    good luck!

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