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Hi all! (newbie) can anyone help? plz have a look!!

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craigarro

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Hi, my name is craig :D and im doing an assignment for my second year electronics BTEC. Im thinking of making a colour identification machine that displays the colour of an object through L.E.D's blue, red, yellow, green and reject white.

Im wondering if anyone has done anything like this before and how did they go about doing it, PLC? micro? etc. any help would be grately appreciated!!! thanx.
 

Are you serious? Good luck!!! But if you find somethink about that, let me know, that looks very interesting.

I think that it is all in sensores, so if yo find sensor that can register the light colour (frequency) than you have done the job. Rest of it is easy. Or you can use tree diferent sensores for red, green, blue (if that even exsists, cause I didnt heard of it. ) Or you can take digital camera from some phone, and use it if you can find datasheet.
 

the_edge said:
Are you serious? Good luck!!! But if you find somethink about that, let me know, that looks very interesting.

I think that it is all in sensores, so if yo find sensor that can register the light colour (frequency) than you have done the job. Rest of it is easy. Or you can use tree diferent sensores for red, green, blue (if that even exsists, cause I didnt heard of it. ) Or you can take digital camera from some phone, and use it if you can find datasheet.
Click to expand...

Basically if you want to make things that can recognize color then you can use the LDR but put a color filter on it.
Use Basic comparator circuit to compare voltage from the LDR with the threshold voltage that you can adjust depend on each color using variable resistor.

If you still have any problem on this then please let me know.
 


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    craigarro

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I agree with fazan83.Use filters(optical filters) to get the desired colr light to fall on the Photosensors and use comparators to detect them.
 

check the attached diagram this will be flexible and accurate as it gives flexibility of programming ( sensitivity, gain, comparing, multi comparing to find white light ):idea:
 

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    craigarro

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we tried something similar to this and

idea that we tried was using a photoresistor and resistor in voltage divider configuration and we fixed the voltage range for each color using the readings for color papers that we had in hand.... we then designed a comparator type ADC with suitable voltage limits to identify the color.......
 

WOW what a good response!!!!! seems like there are some helpfull people on this site, cheers for all your replys youve been very kind.

gona start swatting up on this project and ill let you all know how i get on, my tutor wants me to make something simple like a thermister or op-amp but that'll bore me so im gona go for this and if it fails op-amp it is ha ha!!!! cheers guys.

Added after 25 minutes:

Oh and im gona start with building my sensor tomorow after ive been down to farnells!! i know i might be asking a lot but can anyone recommend a suitible microcontroller????? cheerz
 

I think you can use a CMOS sensor (like those used in digital cameras) . Those sensors contains RGB filters . You can make an analysis of the output pixels and derive the colour of the object
 

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