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AFE4404: AFE4404

Part Number: AFE4404
Other Parts Discussed in Thread: , AFE4405

Hi,
You could show me sample code for AFE4404 with SFH7072 sensor, wich does not need the AFE4404 EVM GUI.
I have one more question with AFE4404 EVM kit what kind of exact compared to medical instrument. ( e.g. HRM, SpO2)
Used on the wrist how much a real vaule?

  • Hi Trapp,

    The register setting of AFE4404 will not change for SFH7072 sensor, only the connections of the LEDs and PDs have to be done properly.
    To use AFE4404EVM without the GUI , you have to build your own software that follows the message communication protocol as discussed in following post.
    e2e.ti.com/.../1884624

    AFE4404 can be used in the medical devices, but that depends on the level of performance you are looking.

    Regards,
    Prabin.
  • HI!
    Thanks for the reply!
    I can solved it and works fine on finger tips, but on the wrist not enough accurate, you have the idea of what the problem might be, calibration or sensor?
  • Hi Trapp,

    Few suggestions to get better signal on the wrist using SFH7072.
    1) Are you using Green LEDs to get heart rate signal? If yes, please make sure to use IR-Cut photodiode (Pin 3 and Pin 10 of SFH7072) as the other photodiode attenuates the Green light.
    2) You can increase the LED current even higher to get the better signal. Please note that this can lead to ADC saturation and which can be mitigated by using the Offet cancellation DAC in the LED phase.
    3) Lastly you can increase the TIA gain ( after DC has been removed ) to amplify the signal.
    4) Avoid noise pick up from the AC mains by running the measurements from battery operated instruments (i.e. Laptop)

    Regards,
    Prabin.
  • Hi!

    I continued my code and i think works fine. 

    I used Broadband photodiode, because i would like to determin heart rate and the SpO2, when i used IR-Cut photodiode the heart rate value was better, but it is still enough.

    Last question,if i would like to use AFE4405 with 2 inputs, I can use my code with little change or i should write it all again?

    Thanks for the reply!

  • Hi Trapp,

    You may have to update the register settings for your code to works with AFE4405. But these changes will be few, I would suggest to go through the datasheet for both the devices along with the register setting and do the required changes.

    Also good luck with AFE4405's code modification.

    Regards,
    Prabin
  • Thanks for reply, helped lot!