Wear OS: How to retrieve raw PPG data from fossil Gen 6 ? (ACCESS-LOCK SUSPECTED)

Question

I’m trying to retrieve raw PPG data from my Fossil Gen6 smartwatch, like other developers who have posted questions below.

Android Wear: How to get raw PPG data?

What is the best way to save and transfer smartwatch sensor data on Android Wear OS (i.e. as CSV)?

After having finished reading through existing relevant posts, I gave it a try to retrieve raw PPG data via SensorEventListener. However, unfortunately, my Fossil Gen6 wouldn’t return valid numbers! To do double-check, I also installed the following app, which is a kind of PPG sensor tester app, in the Fossil Gen 6.

https://play.google.com/store/apps/details?id=io.kuprel.heart_monitor

And then, here’s what I got from the app!!

smartwatch screen

I guess the way to collect raw PPG data of Fossil Gen 6 differs from the previous versions… Perhaps, some kind of access restriction to the PPG sensor value may have been applied in the Fossil Gen 6 series.

So, please tell me the proper way to retrieve raw PPG data from Fossil Gen 6.

Thanks in advance.