TCS230 output problem. HELP URGENT!!!

[thavamaran]

tcs230/2

Hi guys, im working on TCS230, a CMOS color sensor, so im really confused what the problem will be. please someone.


actually my sensor was working well, but the output, when i measured it in oscilloscope, its not stable, like an example.

i triggered to blue filter and measured a blue printed A4 paper, so during my measurement in oscilloscope, it varies greatly, it alternates crazily, like 3,98khz to 4.59khz and then back to 3.8khz, and go back to 4.83 khz, and return back to 3.39 khz, it just keeps alternating. so what i did was, i concluded that external light source is giving too much of trouble and i get a black box, stick it on my PCB all around the white LED and also the sensor, its covering around, the sensor is covered by 1.7cm plastic around it. So when now i measure it, the waveform actually got worst, it varies like hell and there is noise in the waveform now. its getting crazy. i really got no idea what to do.

my circuitry is like very simple, a color sensor and two white bright led by the side of it, i just design it by myself, do anyone can give me idea what would be the problem, please someone, and is there certain specification how the LED must be fixed by the side of sensor? please someone help me. cause once the sensor is stable only, i could do my pixel level analysis and sensitivity analysis.

 

[thavamaran]

tcs230 output

Hi guys, actually im having a problem with my sensor characteristic, its like this, when it reads for an example red, its gives a frequency, when its blue it gives a frequency, but when its capturing both colors, like say in an image there will be a lot colors, so when it captures a pixel with two colors, it averages them, so how can i overcome this problem? what can i do?

 

[FvM]

tcs230 led color

so when it captures a pixel with two colors, it averages them, so how can i overcome this problem?

Yes, that's the supposed sensor operation, to my opinion. So what's the problem actually? The sensor isn't a camera providing spatial resolution...

 

[mfratus]

I've used that chip. It is VERY sensitive, and needs to have good bypass capacitors on short legs very close to the chip, bypassing the power supply.
Remember a white LED is not really white. It is primarily blue with a phosphor which adsorbs blue light and emits red and yellow. Try a light bulb running off of DC, like a flashlight.
The chip could be sensing minute variations in light, also.
There is no lens, so no focus. it only senses what is shined on it. To make it only see what is in front of it, you have to use a lens and a dark tube around it.

Mike