Reading colors

[srspinho]

Hi friends,

I would like to know if it´s possible to read colors with a PIC and a Photodiode.

What I need to do is read a color in the video monitor showed in a small picture box, convert it in a Voltage level and via a lookup table, print the basic color in the LCD.

Have someone ever seen something like this ?

Regards

Sérgio

[BobK]

Hi Sergio,

Goto www.parallax.com and look for Sensors then at the bottom of that page there is Color and Light. They have the TCS230 Color Sensor Evaluation Kit for $79.00. Since the programs they offer are based on their product the Basic Stamp, they are also PIC compatible through PBP. There is also an application article from Nuts & Volts magazine available at that site also.

TAOS, the actual manufacturer of the Kit also makes RGB sensors that can be configured to detect colors. There has been a schematic published in Nuts and Volts magazine that shows how to get logic outputs for different colors using standard CMOS 4000 series logic gates. Not complicated stuff at all.

Have a nice day!

BobK

[jmgelba]

Around the end of last year I was commisioned to design the circuit for a color detecting device for a paint company. The circuit was based around a DSP running at 32MHz and 7 TAOS color sensors and 7 calibrated ceramic LED modules that were custom designed. To do it right, there isnt a PIC available thats even close to powerful enough. Massive amounts of data need to be processed to determine color, shade, hue, contrast, refelectivity, age fade etc etc. You also need to calibrate with Carbon Black otherwise data gets screwy over time. Unless you have access to propriatory information, you are going to struggle to build a nice device.

I did not program this device, just designed the circuit and did the 6 layer pcb layout. This thing was modelled in MATLAB for months before a schematic was even started. Your housing will determine amount of ambient light and thus interfere with your result.

Can you tell its a pain in the butt to do it right?