DCM03 and AFE4490SPO2EVM

Hello Mohammad,

Below are the register settings, AFE was configured with.

Hi Praveen,

I used your suggested settings and at best I obtained the below results.

I then set RED TIA Gain to 25 K and IR TIA Gain to 100K (switched them) and got the below results.

One thing I've noticed is that the results are also very sensitive to how much pressure you place using your thumb and even the specific area of your thumb.

Regardless, looking at the above results, do you have any suggestions to improve the readings?

Thanks.

I posted a reply with pictures, but it didn't go through apparently.

Anyway, I tried your configuration, but wasn't getting any results from RED LED. I switched around the TIA Gains (IR: 100K and RED: 25K) and got the below results.

I've noticed that it's hard to get consistent results. The output varies depending on how hard you press on the sensor and even the area of your thumb being used.

Do you have any specific configuration suggestions looking at the above picture?

Thanks.

Yes your observations about the DCM03 sensor are correct. The PPG data was sensitive to the pressure applied on the sensor and the surface area of the thumb.

Based on the PPG signal waveform, you can increase the Red LED TIA gain by 2x (50k) still operating under 60% of ADC full scale range.

Also the PPG signal has a very good perfusion index (> 2.5%)

Hello, can I ask where you sourced your DCM03s from? I'm from the UK and I am struggling to find samples/a distributor for them.

Many thanks,

Christian

Hello Christian,

You may want to check the manufacturer's website.
http://www.apmkr.com/

Yes I've already emailed the manufacturer (I was just wondering if anyone knew of any distributors in EU/US). Thank you for your response though!

Many thanks,
Christian