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How can we have the accurate signal from the eval-board ADPD105 ?

Hi,

 

We are working on a project using the ADPD105 optical sensor to measure PPG (heart rate and SpO2 values). We are using the evaluation board of the ADPD105. Now we are trying to have the accurate signal out of the evaluation board but every time we have a wrong signal. We installed the driver, we boot up the evaluation board, and we are using the default setting.

  • Hello,

    It's not clear to me what you're seeing from the ADPD105. When you run the wavetool, how are you trying to obtain the PPG signal and what are you seeing?

    Regards,.

    Kevin

  • Hello Buckly,

    Thank you for your help:

    With this configuration :                                                                                                                                                   

    I have this When I run the wavetool :

  • Hello,

    You are getting a response as shown in your data plot. What makes you think this is an incorrect response? You have 1 pulse setup in one timeslot and 8 pulses in the other timeslot. The response in the 8 pulse timeslot is ~8x the response of the 1-pulse timeslot so it appears that this is working as expected. I have no idea what you are using to reflect the LED light off onto the PD. If you are simply putting your finer on the optics then I would suggest you hold still for a while and watch what the data does. You should see a valid PPG signal.

    Regards

    Kevin

  • Hello,

    We want to see a valid PPG signal ( similar to a medical one ) .

    We putted the finger on the optics for more than 5 minutes  and we have this plot.   

  • Hello,

    You currently have your setup running with an internal sample rate of 10Hz and averaging of 8, for an effective output data rate of 1.25Hz. You will not see a typical PPG signal with an output data rate of 1.25Hz. The signal itself is ~1 beat per minute. Try changing your internal sample rate to 100Hz with averaging of no more than 4 to start with. Then set your LED currents so you can be sure you're not saturating the inputs. If you do that you should begin to see a more familiar PPG signal.

    Regards,

    Kevin