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TCS230 light sensor theory

  1. Apr 17, 2009 #1
    Hi guys, i been recently implementing TCS230 for my final year project, so i have did few experimental stuff on TCS230 and applied few theory for the methodology, first experiment was TCS230 without LED illumination and with just fluorescent light illumination, i got some result and it was not good and i prove it with Fermat's principle, then i did experiment with LED illumination and i prove the theory with lamberts cosine law. im planning to do more experiment with TCS230 and prove some of light or wavelength theory, what kind of experiment can i do?

    Since TCS230 output is frequency base, can i calculate the wavelength with c=f.lamda? is all the visible color has the same speed of light? This particular TCS230 has internal light to frequency converter, i cant find any info on this particular device, how actually it works? please help me, i have tried research across net and books, but i cant really find any reliable source for all this question, please do help me.
  2. jcsd
  3. Apr 17, 2009 #2


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    Staff: Mentor

    Welcome to the PF. From a quick google search, the TCS230 is an RGB photodiode converter to a frequency output signal. Looks to be for light level sensing and color sensing.

    Fermat's principle has to do with refraction of light, and would seem to be unrelated. Lamber's Cosine Law relates to reflectance off of surfaces (gotta' love Wikipedia.org). What exactly do you want to do? And yes, the speed of light in a vacuum and in air is the same for all colors. There are some media that are dispersive, but you will probably not run into that in your experiments.
  4. Apr 17, 2009 #3
    Hey berkeman, you are right about fermat's principle for refraction and there is laws of reflection which using fermats principle as methodology.

    Check it out here:

    http://http://hyperphysics.phy-astr.gsu.edu/HBASE/phyopt/Fermat.html" [Broken]

    So the thing is i am not satisfied with the experiments i did with TCS230, i have this thought that i could perform more on this sensor, so as you know its directly got to do with light, what else experiment i can do with this sensor, may be through illumination, surface, or wavelength or whatsoever, so i dont really have any idea right now, so i need ideas from pros like you, please help me. let me tell you in detail about the experiments i done so far.

    1st was i used this color sensor without any diffuse illumination and only got the reading which fluorescent lights illumination in my lab, therefore when i read the through the medium which is an A4 paper printed with colors and my sensor on top of it, so there was no proper reflection and only shadow left, so i prove this with laws of reflection correlated to fermats principle.

    2nd i did a new board with White Led, white led because through my research i found that white led blocks other ambient light, correct me if im wrong, then the output was perfect with i measured the same color with diffrent intensity, which from dark to bright, like an example for red, from 0 to 255, and the output keep increasing according to brightness. so i prove the diffuse reflection works fine with lamberts cosine law.

    now i need idea to further extend my experiment, i really want to squeeze out everyting i need to know about this, please give me idea, i just need idea with some guidance, im not really good with physics, sorry about that.

    another thing is how actually this internal light to frequency converter works, i really couldnt get proper resource on that, please guide me as well.

    Thank you!!
    Last edited by a moderator: May 4, 2017
  5. Apr 17, 2009 #4
    The TCS230 does NOT convert the visible light to frequency. It has outputs that put out different frequencies (few kHz to 500 kHz) for various color (red green blue) light illumination. Read the data sheet.
  6. Apr 17, 2009 #5


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    If you want to play with different colors to see if you can reproduce the data-sheets "PHOTODIODE SPECTRAL RESPONSIVITY" you could use filters, vary the intensity, and record the frequency output. http://www.edmundoptics.com/" [Broken].
    Last edited by a moderator: May 4, 2017
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