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Help me build a colorimeter and choose sensors for it

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UroBoros

UroBoros

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Hai

I have to impliment a Colorimeter to mesure the concentration of a solution using Coloured light sourses (Preferabily LEDS). Without using light filters but by coloured LEDs.

readouts using LCDs using a, microcontroller.

Which are the best sensitive light sensors and emitors which will be ideal for my purpose?

Please suggest helping links

picstudent
 


    UroBoros

    UroBoros

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concept of colorimeter

hi
u can chose led based on WL u require.
but with this u can do analysis only at one WL,
To eliminate filter u can chose different led at different WL, and shift this led positions according to WL required this way also u can avoid filters.

In market there are available light to frequency converter.
Interface this frequency to micro controller.

All the best
Babesh
 

    UroBoros

    UroBoros

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colorimeter sensor

Hai
Thanks for the replys.


In that sensor range there is normal light to voltage converters as well as light to frequency converters.

What is the purpose of using light to frequency converters ? More resolution?

Colorimeter measurments require light to frequency converters for accuracy or we can use light to voltage converters also?

Thanks again.
picstudent
 

light to frequency converter project

You can try both ..

Some years ago when microcontrollers and A/D converters were not as common as they are today, you could buy voltage-to-frequency converters, and frequency was just easier to measure - just by counting pulses using for example TTL counters ..

Nowadays AD converters are cheap and readily available and I wouldn't bother to use something-to-frequency converter .. unless it is an unique sensor/converter that is difficult to replace ..

Regards,
IanP
 

    UroBoros

    UroBoros

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light frequency sensor

hi picstudent

the very purpose of using light to frequency converter is to avoid noise interference.

Signal conditioning of light to voltage converter is a bit tedious it requires grounding, shielding, etc..
Beter to go for light to frequency sensors.

tks
Babesh.

Added after 2 seconds:

hi picstudent

the very purpose of using light to frequency converter is to avoid noise interference.

Signal conditioning of light to voltage converter is a bit tedious it requires grounding, shielding, etc..
Beter to go for light to frequency sensors.

tks
Babesh.
 

    UroBoros

    UroBoros

    Points: 2
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building a colorimeter

hey, i'm working on the concept of colorimeter.. for implementing a glucometer. but in this process i ve come across a problem. i'm using a LED and an LDR. i can now obtain the resistance across the LDR. how do i proceed further?? do i need to obtain the voltage across the LDR or shld i use ohm to frequency converter to use a microcontroller?? plz help me design the cricuit.

thanks,
 

colour light to voltage

Hi 23/11,

From u r ckt what i can understnad is that u need to tap voltage accross LDR to get Proportional response for your gluco levels..

all the best
--babesh
 

colorimeter with light filters

hey.. BABESH

actually here.. since the resistance changes according to the intensity of the light and also since here it is acting like a voltage divider.. so the voltage across the LDR remains constant.. or might vary in close proximity.... dont u tink so??
 

Colorimeter sensors?

It is voltage divider then the voltage will change with change in LRD resistance,

The resolution may be less, it is depends on the applicatoin u r looking,

implement a BUFFER ckt while measuring voltahe
 

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