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AFE4404 LED usage and algorithm

kevin lin97
Prodigy 50 points

Other Parts Discussed in Thread: AFE4404

Hi,

I have read the TI AFE4404 firmware code for MSP430 and test it using an third party module with AFE4404 and costom LED.

I see the firmware use only "LED1 - Ambient Data" to calculate hear trate, and the result seems good enough. So I wonder when to use LED2/LED3 data?

Usually the LED1 is green, LED2 is red, LED3 is IR, right? When should I use these LED is different situation?

I am currently study on developing our own algorithm to detect heart rate, and satisfied with the result without motion artifact.

With motion artifact, how to eliminate its effect and keep the result accurate? I saw some solution use an accelerometer, 

but I have no idea how to apply the data of accelerometer to the heart rate algorithm.

Any suggestions or clue would be helpful.

Thanks.

  • 0
    TI__Guru 50036 points
    Hi Kevin,

    We have received your inquiry regarding the application implementation of AFE4404 and hope to have some answers back to you shortly.
  • 0
    TI__Guru 50036 points

    Hi Kevin,

    The usage of a specific LED (Green / Red / IR) typically depends on the application.
    You could use any of the three LEDs for extracting the Photoplethysmogram signal using reflective PPG technique.
    We have seen Green LED being used for the wearable / wrist based applications due to its wavelength (penetration depth) and reduced susceptibility to motion.

    Regarding the algorithm for HRM with motion compensation, we do not hold expertise on this topic and I will let the experts in the community to respond to this. I know that there is lot of IP revolving around this and I suspect if anyone will be willing to share this information.