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Topic: where can i find a circuit of Pulse-oximeter ??help! help! (Read 503 times) previous topic - next topic


I need to make a Pulse-oximeter ,but i can't find the circiut.
who can help me !
thank you !


Google? 31,200 hits for the search string 'Pulse-oximeter arduino'
Beginners guide to using the Seeedstudio SIM900 GPRS/GSM Shield


Google? 31,200 hits for the search string 'Pulse-oximeter arduino'
it is difficult to browse google.so...


it is difficult to browse google.so...

Then use a search machine that works in your country.

// Per.


There are so many out there, but I thought this one looked cool:



I'm also building a pulse oximeter/heartrate monitor! I've used more or less the circuit in this tutorial: instructables. Extracting the pulse rate wasn't so difficult (just filter, filter, filter 'til you get rid of enough hi-freq noise) but i haven't been able to get a quantitative SpO2 reading yet. However i can clearly see the ratio ir/(red+ir) changing when i hold my breath so it's just me who need to learn some more programming. A more detailed description of a professional implementation can be found here: Texas Instruments. Things become much more complicated when trying to measure both heartrate & oxygen saturation (semi)simultaneously - for the oxygen you need both wavelengths, and for the heartrate you need continuous samples of one (pref. ir) over a justifiable time period. Switching between wavelengths more or less excludes the use of analog lowpass filters, so the raw signal will be extremely noisy. This problem is discussed in depth in the TI app note above, though i'm working with digital filters only since i want to keep the need for extra hardware to an absolute minimum.

Anyone else doing something similiar? I'd love to hear about your experiences. As i've said i'm really close to getting it all to work using the very simple circuit from Instructables with only a standard-issue opamp. If/when i get it to work i'll of course post the source (ah, the shame...my programming is completely amateurish).

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