Polar Sensor Logger

Jukka Happonen

About this app

This application can be used to log HR and other raw biosignals from the Polar H10, OH1 and Verity Sense -sensors. It uses Polar SDK (https://www.polar.com/en/developers/sdk) to connect sensors.

One of the application's core feature is to save received sensor data to files on device, that can be then later accessed eg. via PC. User can also share saved files to eg. Google Drive or email them.

Verity Sense:
- HR, PPi, Accelerometer, Gyro, Magnetometer and PPG

OH1:
- HR, PPi, Accelerometer and PPG

H10:
- HR, RR, ECG and Accelerometer

H7/H9:
- HR and RR

Application also supports sensor data forwarding using MQTT-protocol.

Sensor firmware requirements:
- H10 firmware 3.0.35 or later
- OH1 firmware 2.0.8 or later

Permissions:
- Device location and background location: In order to scan bluetooth devices, device location is required by the Android system. Background location is required in order to seek devices if application is not in the foreground.

- All Files Access Permission: Data from the sensor is saved to files on the device and then they can be emailed, saved to Google drive, access via PC, etc...

- Internet: Data sending to MQTT-broker

Privacy Policy:
This app does not collect user data (location/etc...)

This application was made for my own purposes and it is not an official Polar app nor supported by Polar.

Tested with Sony Xperia II Compact (Android 10), Nokia N1 Plus (Android 9), Samsung Galaxy S7 (Android 8), Sony Xperia Z5 Compact (Android 7.1.1)

Here are the most frequently asked questions about the application:

Q: What is the timestamp format?
A: Timestamp format is nanoseconds and the epoch is 1.1.2000.

Q: Why nanoseconds?
A: Ask from Polar :)

Q: What are the extra columns in HR data?
A: They are RR-intervals in milliseconds.

Q: Why there are sometimes 0-4 RR-intervals?
A: Bluetooth exchanges data around 1 s intervals and if your heart rate is around 60 bpm, then almost every RR-interval hits between data transmission. If you have heartrate eg. 40, then your RR-interval is over 1s => not every BLE packet contain RR-interval. Then if your heartrate is eg. 180, then there is at least two RR-intervals in BLE packet.

Q: What is the ECG sampling frequency?
A: It is around 130 Hz.

Q: What does ECG, ACC, PPG, PPI mean?
A: ECG = Electrocardiography (https://en.wikipedia.org/wiki/Electrocardiography), Acc = Accelerometer, PPG = Photoplethysmogram (https://en.wikipedia.org/wiki/Photoplethysmograph), PPI = Pulse-to-Pulse Interval

Q: What does "Marker"-button do?
A: Marker button will generate a marker file. Marker file will hold timestamps when the marker is started and stopped. You can use the marker to mark some events during the measurement.

If you have more questions, please drop me an email!

Privacy policy: https://j-ware.com/polarsensorlogger/privacy_policy.html

Thanks to Good Ware for few images!
Marker icons created by Good Ware - Flaticon

Ratings and reviews

Like being able save the log files and how the graph rescales itself to more fully show the heart rate and trends. I use it to to see how my HR is changing over the workout and calculate the average over the last 5 minutes or so to enable a comparison to my lactate level. I took off a star because at the end it looks like I'm saving to my Google Drive folder on my phone, but it never saves. After the workout I have to go to my Files app, then Internal Storage, find the log file and then share with Google Drive folder (which I then open in Excel on my PC)

I love the simplicity of this app and the access to the raw data. However, sadly it does not work on my new phone which is a Pixel 9 pro XL. It was a user error, My new phone did not allow the polar sensor logger to write to the default file location. Once I made a new folder on the phone everything worked as I had hopped.

It works great once you figure out how to keep the phine from stopping the connection. Some phone will stop the connection to prioritize another app connected to the same device. I now use a second device (phone or computer) to record data when needed.

What’s new

- Bugfix when HR receiving is stopped
- Fixed incorrect "Disconnected" text when feature is not availble in sensor