Samsung Galaxy Watch 4 HR_RAW sensor processing

Samsung Developer Program
1

I’m developing an app to retrieve PPG information from Samsung Galaxy Watch 4. I noticed HR RAW sensor (com.samsung.sensor.hr_raw) generates data at 25 Hz and each data point is an array of 16 floating values.
What do each of those 16 values represent and what king of filtering or post processing should I perform in order to retrieve the PPG information?

There is also PPG Batch sensor (com.samsung.sensor.ppg_batch). However, when I’m trying to retrieve the data from this sensor no data is generated. What is the purpose of this sensor and how do I retrieve data from this sensor?

I couldn’t find any documentation on these sensors anywhere.

Appreciate the help.

1 Like
2

The sensors Data API is documented in Android Developer Documentation. Here is one for Health Sensors

Ron
Samsung Developer Relation

3

I have already looked at the android documentation. I can get the heath and fitness data such as heart rate, blood oxygen, steps, sleep, etc. However I’m unable to make it work for getting PPG signal. There is no health data type defined for PPG in the Android Health API.
So, the only option I can think of right now is to directly process the raw sensor values from the above mentioned sensors.
However, I’m unable to make sense out of those senor values as there is very little to no documentation available online for those specific senors.
Is there any documentation or datasheets available for those sensors?
A code snippet or techniques or algorithms for retrieving or filtering PPG signal from the sensor is much appreciated.

Thanks for the help

4

I’m having the same issue, Tizen web apps would allow retrieving PPG signals, but WearOS Watch 4 apps doesn’t seem to have access to PPG signals just yet (although the sensor exists programmatically).

Did you find the fix yet?

To anyone : does this question best fits WearOS Google Help Community or Samsung Developers Forums? I’m thinking that sensor access is related to OS, so I will be also posting this question on Google Help Community.

1 Like
6

Any update on this?

We are searching for the same thing: retrieving PPG signal from Galaxy Watch 4.

7

(post deleted by author)

8

I’m having the same issue with retrieving accelerometer raw data… any news on this?

9

For health read the Android Health API training.

For the accelerometer data see the Android motion sensor documentation.

These are not really Samsung Developer Questions and should be brought up on the Android discussion groups.

Ron
Samsung Developer Relations

11

Dear Ron,

In my opinion, those are Samsung Developer questions as they are related specifically to the Samsung device sensors and the meaning of the produced measurements. Following this StackOverflow question I managed to register listeners for the data produced by the sensors.

As @maxa90, I am not receiving any data from PPG Batch sensor (com.samsung.sensor.ppg_batch).

Again as @maxa90, I am getting 16 float values for the HR RAW sensor (com.samsung.sensor.hr_raw), but I don’t understand the meaning of those values.
Is there any documentation where I could read about the meaning of those values?

Below you’ll find the exemplary 16 values produced by the Samsung HR Raw Sensor:

2022-03-14 13:16:38.307 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.939215E-39
2022-03-14 13:16:38.308 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 3.676067E-39
2022-03-14 13:16:38.308 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 0.0
2022-03-14 13:16:38.309 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 0.0
2022-03-14 13:16:38.311 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 3.672195E-39
2022-03-14 13:16:38.312 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 3.02545E-39
2022-03-14 13:16:38.313 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.942194E-39
2022-03-14 13:16:38.314 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 3.02545E-39
2022-03-14 13:16:38.317 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.943137E-39
2022-03-14 13:16:38.320 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.321 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.322 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.322 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.323 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.324 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.938736E-39
2022-03-14 13:16:38.326 13563-13563/? D/Sensor: Samsung HR Raw Sensor: 2.5E-44

Best,
Michał

12

All I can do is point you to the three recent blogs for Samsung Health/Health Services on Wear OS

I hope those get you started.

Ron

13

Hi All,

@maxa90, @kevv96, @developerA4G, @za.yonit and @michalg have some of you figured this out?

Thanks and best

14

That’s what you are looking for the last set of numbers is the PPG. Plot it on a graph against the time on X -axis