How to grab the color from RGB code fetched from LDR?

[Stig124]

Hello,

I have an assignement that I'm struggeling with :

I need to use a Pololu Zumo 32U4, and a color sensor made from LDR + RGB LED (schematic attached)

I'm able to successfully fetch the RGB codes (see the code)

Code (too long to fit on the post message)

But I actually need to recover the color that that RGB code signify

I have a checkerboard with 6 colors which are [Black, White, Red, Green, Blue and Yellow], and the robot will need to make a specific action after having scanned the color

Black and White will not be an issue though as Black report as ~{0,0,0} and White ~{255,255,255} due to the calculation method used

But the issue here is the other 4 colors, especially Yellow

I was thinking about a percentage-based method but the yellow will effectively not work as it will only use the three primary color and I couldn't find the minimal percentage of Red and Green needed for that color to be actually Yellow

If someone had an idea that would be awsome

Thanks in advance

[UKHeliBob]

What are the RGB values for each of the colours ?

[Stig124]

I can't know for sure actually, I need to make a range that will lock the color, as the sensor is not that precise and very sensible to environement light

Oh, I just found a way while typing that, I'll retake mesures when I'll be able and setup ranges (That yellow will still be an issue though)

Thanks anyway

[wvmarle]

You have to set ranges indeed, and do consider shielding your sensor setup from ambient light as it will otherwise seriously mess up your readings.

[UKHeliBob]

Maybe sum the RGB values read by the sensor like this

unsigned long value = (R << 16) + (G << 8 ) + B;

then testing whether the result is in one of the required colour ranges having derived the ranges by empirical measurement