Infrared CO2 sensors for capnography

[[email protected]]

Hi,

I'm an italian electronic engineer and I'm planning to design a
capnography system.
It will be made with a circuit that uses a microchip pic and datas will
be sent via rs232.
Please can you give me a list of Co2 infrared sensors that can be
useful form my purposes?
I know that for pulse oximetry TAOS produces light-to-voltage
converters ; i would like to know If TAOS products are useful for
capnography as well; or, alternatively, any other manufacturer for this
kind of sensors (wich are tested on capnography systems).
Thanks in advance for your reply.

Paolo

[email protected]

 

[[email protected]]

Hi,

I'm an italian electronic engineer and I'm planning to design a
capnography system.
It will be made with a circuit that uses a microchip pic and datas will
be sent via rs232.
Please can you give me a list of Co2 infrared sensors that can be
useful form my purposes?
I know that for pulse oximetry TAOS produces light-to-voltage
converters ; i would like to know If TAOS products are useful for
capnography as well; or, alternatively, any other manufacturer for this
kind of sensors (wich are tested on capnography systems).
Thanks in advance for your reply.

http://www.rcjournal.com/online_resources/cpgs/co2mvcpg.html

Capnography means measuring CO2 concnetrations in gas streams.

Here is a particularly crude IR spectrum of CO2

http://science.widener.edu/svb/ftir/co2.jdx

Here is a detailed picture of the P and the R branches

www.dynament.com/applications/an0004.pdf

Tony Williams reported a particularly sad tale of an LED which emitted
bang on one of these narrow absorbtion lines all through lab testing,
but which shifted a bit when used on the colder shop floor so that it
missed the line ... he went over to a broader-band source that always
sampled a fair number of lines (and would have given a non-Beers Law
calibration curve).

 

[Paul Burke]

Tony Williams reported a particularly sad tale of an LED which emitted
bang on one of these narrow absorbtion lines all through lab testing,
but which shifted a bit when used on the colder shop floor so that it
missed the line ...

How hard would it have been to keep it at constant temperature, e.g.
with a Peltier thingy?

Paul Burke