DIY pulse oximeter

This pulse oximeter turned out very nicely. It is based around a Freescale microcontroller and detects pulse as well as oxygen saturation in your blood. The sensor is made of two wood pieces and allows two wavelengths of light to be shined through your finger. A sensor picks up the light on the other side of your stubby digit and the readings are compared to calculate saturation. Check out the finished project after the break.

We saw an Arduino-based oximeter a few months ago. These kind biometric hacks are rare around here. If you’ve got a well documented project don’t forget to tell us about it.

[Thanks Michael]

Comments

  1. Stephen says:

    Sounds like a hypochondriac modders wet dream.

  2. dan says:

    I bet when a hospital buys one of these it costs £several thousand.

  3. Drakonite says:

    Hey, thanks neat. But I gotta ask; why the alarm at 75bpm? Or was that just to demonstrate it supported an alarm?

  4. Drakonite says:

    Er… That should have been “Hey, thats neat”. I blame the proximity of the keys on my keyboard!

  5. mb1988 says:

    @Drakonite
    Alarm at 75bmp was just a demonstration ;-).

  6. Dick Cheney says:

    How is it calibrated? Commercial devices use look-up tables derived from volunteers, what about this one? This, to me, seems the greatest challenge for a home-built pulse oximeter.

  7. mb1988 says:

    In this case no blood was spilt during tests :P. But actually it uses empirical look-up tables found in some medical papers.

  8. tim says:

    direct link please, no download with google translate

  9. Skyler says:
  10. bothersaidpooh says:

    could it be modified to detect carboxyhemoglobin (aka CO saturated) ? could be very useful as a quick test for CO poisoning..

  11. Anon says:

    This was on Hackedgadgets first, btw.

  12. Rob says:

    @anon

    I bet it was on http://www.elektroda.pl/rtvforum/topic1655378.html first, tbh.

  13. Dan Fruzzetti says:

    now please find a way to do just this exactly, but testing for blood sugar.

    the pharmaceutical companies don’t care enough about their patients to do this quickly so diabetics are sticking themselves all the friggin’ time.

  14. Rachel says:

    @bothersaidpooh

    I very much doubt it can reliably detect CO. The sensor works by measuring the absorbency spectrum of the blood. Oxygenated hemoglobin appears much redder than deoxygenated. Unfortunately, CO binds in place of O2, also giving it a red colour.

    CO binds much better than O2, so it tends to stay in the blood longer, making it appear a bit more oxygenated than normal to this sensor. Maybe if you had a baseline to work off of, but it can’t distinguish CO poisoning from more oxygen, like from hyperventilation, or an oxygen tank.

  15. Amos says:

    “Shined” is what was done to a formerly tarnished piece of metal. “Shone” is what light did through a translucent material.

    I know, English can be pretty weird…

    Cool project, BTW :P

  16. MiG says:

    @bothersaidpooh

    As Rachel said, CO bonds to the hemoglobin in the place of O2 and gives it a very red, flushed color. If someone is exhibiting Signs and Symptoms of CO poisoning (skin very flushed, Headache, Nausea, Malaise, altered mental status, etc..) they will also have an SPO2 reading of 100%. At the current time I know of no SPO2 meter than can tell if someone has CO poisoning…but hopefully the healthcare professional treating you will recognize the distinct signs and symptoms and treat you with O2 therapy accordingly.

    So, the short and sweet answer is no, not that I know of.

  17. Klaus Leiss says:

    A Pulse CO-oximeter is basically the same as an
    Pulse Oximeter but uses more different light colours. According to the german wikipedia they use
    seven different colours.
    The english article

    http://en.wikipedia.org/wiki/CO-oximeter

    states only several wavelength.

    Klaus Leiss

  18. Valiant says:

    Speaking as a trained emt and firefighter, AND as an exercise nut, thats a pretty useful hack. i know that i’d love to have an oximeter on hand when i’ve been working out.

    definitely more helpful than that $40 dollar heart monitor watch. peice’o’crap.

    but as a gamer, i was wondering how hard it would be to output the info and incorporate it into a homebrew game..sony’s been working on something like that but it’ll be a while before it hits the market.

  19. TXMedic says:

    Alright that’s pretty awesome. As a FF/Paramedic I always like hacks that involve the healthcare field.

  20. mei says:

    do you have any idea how to make a pulse oximeter SIMULATOR?

  21. ash says:

    hai there, love the concept of spo2, using arduino its ?could u share source code?can email to me

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