AFE 4404 Eval Board Outputting Noise as Data

D.O.

Other Parts Discussed in Thread: AFE4404, AFE4490

Hi,

I bought the AFE4404 eval board but I'm not getting any reasonable data out of it. I used the default values, reset the EVM to default, changed the currents to about 60 mA, changed the gain to about 250K, set the calibration option, used the notch filter (I tried combinations of all the settings adjustments I listed). I've attached a sample waveform taken with default values. Please do you know what the problem might be?

Thanks,

over 9 years ago

0 D.O. over 9 years ago

Prodigy 100 points

0 Amy Schnoor over 9 years ago in reply to D.O.

TI__Mastermind 18285 points

D.O.

How are you taking these measurements? Wrist? Finger?

0 D.O. over 9 years ago in reply to Amy Schnoor

Prodigy 100 points

Hi Amy, I strapped it onto my wrist with a wristband for the attached waveform. I also put it on my finger.

0 Amy Schnoor over 9 years ago in reply to D.O.

TI__Mastermind 18285 points

D.O.,

Have you tried isolating the sensor with electrical tape? See Figure 6 of the User's Guide.

Are you running the PC on battery power? If not, please do.

0 D.O. over 9 years ago in reply to Amy Schnoor

Prodigy 100 points

You were right. I was running the PC from the mains and power line noise was coupling into the signal. Thanks.

0 Amy Schnoor over 9 years ago in reply to D.O.

TI__Mastermind 18285 points

D.O.,

Glad I could help.

0 Janez Gramc over 9 years ago in reply to Amy Schnoor

Prodigy 10 points

Hi,

I have a task to do HR and SPO2 measurement on the wrist. For this purpose I have modified the AFE4490EVM optoelectronic part and I get good response to the wrist.
Now I'm doing a survey with AFE4404 EVM. Unfortunately, I can’t get good response even with the original Sensors. The signal is very disturbed, only green gets some results and there is no outcome on wrist.

Yes, I run the PC from main supply, such as I do with the AFE4490.
Would you give me some more advice how to improve the response?
Would you explain the comparison between the AFE4490/AFE4404 in more details?
How do I switch between a 2-LED 3-LED LED mode at the AFE4404?

Thank you,
Regards,
Janez

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AFE 4404 Eval Board Outputting Noise as Data