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Comments 9

  • Really Homemade Oximeter Sensor 18 days ago

    Hi, for this project I've used the detector in the KY-39 but I didn't find online which type of photodiode it is.
    Now I'm also truing to build it from scratch. I've tried the LTR-301 but it is not good, the spectral response is quite narrow around 940nm. So it doesn't receive the red light.
    Now I'm waiting the arrival of LPT 80A which can receive both red (600 nm) and infrared (940 nm) light.

  • Really Homemade Oximeter Sensor about 1 month ago

    Quite sure the photodiode of my KY-039 sensor isn't a LTR-301. Better reading the datasheet of the LTR-301 I've noticed that it has a narrow spectral range around 940nm, so it will not receive the red signal! We need a wide range photodiode maybe like the LPT 80A, which can receive better also the 600nm of the red led light. I'm looking also better online to find another photodiode with a better response from 600nm to 940nm.

  • Really Homemade Oximeter Sensor about 1 month ago

    Sorry for my late reply, I've built the sensor from scratch using an LTR-301 photo transistor, and now I've the same problem. Maybe the photo transistor of the KY-039 sensor isn't an LTR-301 and it's a bit different. The result isn't correct with Red and Infrared traces reversed.

  • Really Homemade Oximeter Sensor about 1 month ago

    I'm not able to answer you in a precise way: a friend of mine suggested to implement this http://www.bristolwatch.com/ele2/pdiode_op_amp.htm - But I didn't try.

  • Really Homemade Oximeter Sensor about 2 months ago

    Every new oximeter need calibration, because leds and photo diode could be different from mine. So in the article I explain how to calibrate the sensor with working oximeter. Tested with a real oximeter mine is not as stable as one bought in a store.

  • Really Homemade Oximeter Sensor about 2 months ago

    It doesn't detect CO, but SpO2, the oxygen saturation: https://en.wikipedia.org/wiki/Oxygen_saturation_(medicine)
    I think your link is spam :-/

  • Really Homemade Oximeter Sensor about 2 months ago

    As you can see my circuit doesn't have a filter and doesn't have an amplifier. the signal is processed as it comes from the photodiode. The magic happens mantainig the sum of the last measures (which are also an average of many measur in T milliseconds). This method is better described by John Ha in his project (it's linked).

  • Really Homemade Oximeter Sensor about 2 months ago

    no, just one! I have an arduino uno.

  • Really Homemade Oximeter Sensor about 2 months ago

    Thank you! If you try it let me know your result! Bye!

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