How to measure frequency of light color using TCS3200-DB???

Abdul Hakim

Hi,

My name abdul hakim and I am student from departement of physics of Institut Teknologi Bandung Indonesia...
I have a final project about measuring the frequency of a leaf color by using TCS3200-DB...
But I don't know how to do it...

We know the spektrum of a light color at range THz, and I stil don't know ho to measure it since the frequency is too large, therefore is there anybody know how do I measure the frequency at that range??

Please I really need help...

Thank you

Mike Green

You're a physics student. What's the relationship between frequency and wavelength? The datasheet for the TCS3200 gives graphs of the response of the sensor at different wavelengths. Have you read the datasheet? What do you understand about the way the sensor functions? Since this is a final project, you need to put in some effort in learning these things if you don't already know them. We can help you, but you have to show that you're putting in some effort.

ElectricAye

Abdul,

you will not be able to measure the frequency of the light directly, but you can derive the frequency range based on the different responses you will get from the RGB (wavelength dependent) sensitivity of the TCS3200-DB. The TCS3200 has an array of photodetectors, each with either a red, green, or blue filter, so you can switch filters to get different response curves. If you need to measure the light at a very specific frequency (via wavelength), then you will need to get some sort of external filters that will narrow the range, for example interference filters or laser line filters, etc. The filters that are already built into the TCS3200 are not very specific. Another way of deriving information from such a system might be to use an assortment of LEDs, each of which that emits a different wavelength. By testing different combinations of illuminating LEDs and TCS3200 filters, you might be able to derive better wavelength resolution.

atok_91

hye, i am unable to get a square wave from oscilloscope when i connect tcs3200 output(pin6) to the oscilloscpe, iam using infrared (s2 & s3 low) for the sensor? can you correct me, maybe circuit or the sensor cant detect the infrared.......

ElectricAye

atok_91 wrote: »

hye, i am unable to get a square wave from oscilloscope when i connect tcs3200 output(pin6) to the oscilloscpe, iam using infrared (s2 & s3 low) for the sensor? can you correct me, maybe circuit or the sensor cant detect the infrared.......

Based upon its spectrum, the TCS3200 is able to detect near IR in the range of about 800 - 950 nm, and a little bit beyond that. So I guess it depends upon what you mean by "IR." For example, this sensor is NOT going to detect heat from a person's body. The wavelength that a "Passive InfraRed" (PIR) device can detect is much longer than that. But, yes, to get the sensor to selectively detect the red part of the spectrum, you will want to drive pins 2 and 3 low. Make sure you have your enable pin and S0 and S1 set properly, too. Then test with visible red light before you try the sensor into the near IR range.

Hope that helps.

Phil Pilgrim (PhiPi)

The lens in the TCS3200-DB has an IR-blocking filter, which prevents IR from reaching the sensor. This is necessary to prevent IR from masking the visible color response, which is what the TCS3200 is designed for.

-Phil

atok_91

hye electric aye, what did u mean by visible red light? red diode...? and my S0 & S1 is high, is that correct configuration for it to detect red colour?

ElectricAye

atok_91 wrote: »

hye electric aye, what did u mean by visible red light? red diode...? and my S0 & S1 is high, is that correct configuration for it to detect red colour?

My apologies. Are you working with the raw tcs3200 chip, or are you talking about the Parallax product, the tcs3200-DB????

There are product data sheets for the tcs3200-DB here:
http://www.parallax.com/Store/Sensors/ColorLight/tabid/175/ProductID/429/List/1/Default.aspx?SortField=ProductName,ProductName

If you are talking about the raw chip, then look here for the data sheet:

www.taosinc.com/getfile.aspx?type=press&file=TCS3200-E11.pdf

For the raw chip, S0 and S1 can be high if you want the chip to output the max number of pulses per second when it detects light. These pins scale how many pulses per second are output when the chip receives light. You can scale that output by changing the values of those pins.

To switch color filters on the chip, you change the value on pins S2 and S3. Both S2 and and S3 need to be set low if you want to look at the red end of the spectrum. You need to consult the data sheet to see which physical pins on the chip correlate to S2 and S3, etc. As Mike Green would say, the data sheet is your friend.

As for testing your set up, use a red LED to see if you get any output at all. You don't want to test for IR if your chip can't detect red light that you can see. (You can't see IR, as you know.)

atok_91

im working with raw material of tcs 3200(2nd link).... im using the infrared thermometer, its infrared that i used to check the sensor output at oscilloscope, however, i havent use red led, i will inform after using it....
thanks for the feedback.....

ElectricAye

atok_91 wrote: »

..... im using the infrared thermometer, its infrared that i used to check the sensor output at oscilloscope,.......

Please note that the type of IR detected by heat sensors is a much longer wavelength than this TCS3200. See my post above with the spectrum chart. For example, heat from a human body would be about 5000 nm to 14000 nm (I think), which is WAY off the scale for the TCS3200. So if your intention is to make a thermometer, then the TCS3200 is probably the wrong chip. The TCS3200 chip is primarily designed for light you can see, but it can pick up a little bit of the NIR (near infrared) spectrum.

atok_91

im using it and it gives output in square wave(as written in its datasheets)...
thanks for helping