Welcome Guest,Register Now
Log In

ANT Forum

Welcome guest, please Login or Register

   

HR Data and RR Intervals

Rank

Total Posts: 4

Joined 2020-02-05

PM

Hello.
I used sample code in my app.
On the screen and my HR data log I see that HR data updating is more frequently than real heart beats.
On one real heart beat HeartBeatCounter is increased by 4-5. CalculatedRRInterval receives more frequently too.
Data on the screen and log file writes direct from parameters of CalculatedRrIntervalReceiver() and HeartRateDataReceiver().
But ComputedHeartrate in HeartRateDataReceiver() is correct.
What's wrong?
     
RankRankRankRank

Total Posts: 139

Joined 2012-06-27

PM

How are you arriving at the following statement: "On the screen and my HR data log I see that HR data updating is more frequently than real heart beats. On one real heart beat HeartBeatCounter is increased by 4-5."

The profile specifies that this counter increments once per beat.

Note that the computed heart rate may remain constant across consecutive beats.

Ian      

Signature

Ian Haigh

Rank

Total Posts: 4

Joined 2020-02-05

PM

It seems that the problem is in the HR chest belt. It transmits incomprehensible data. HR is 74-75, but HR belt transmits increment BeatCount in every page. I don't understand it... HR belt build on nRF51422 (ANT+ and BLE).
Data from SimulAnt:
945801734 Rx[04][55][17][BE][55][C1][A8][4A]
945801968 
Rx[04][55][55][C1][93][C4][A9][4A]
945802218 
Rx[04][55][93][C4][BB][C7][AA][4B]
945802468 
Rx[04][55][BB][C7][EE][CA][AB][4B]
945802718 
Rx[84][55][EE][CA][21][CE][AC][4B]
945802953 
Rx[84][55][21][CE][54][D1][AD][4B]
945803203 
Rx[84][55][54][D1][87][D4][AE][4B]
945803453 
Rx[84][55][87][D4][BA][D7][AF][4B]
945803703 
Rx[04][55][BA][D7][ED][DA][B0][4B]
945803937 
Rx fail
945804187 
Rx[04][55][2B][DE][69][E1][B2][4A]
945804421 
Rx[04][55][69][E1][A7][E4][B3][4A] 
     
RankRankRankRank

Total Posts: 139

Joined 2012-06-27

PM

Yes that looks to be an incorrect transmission by the sensor. The beat to beat time seems to be fixed at 333 * (1/1024 sec) = 0.325 sec

I recommend that you report this to the sensor manufacturer. Does the sensor appear in our directory?

Ian      

Signature

Ian Haigh

Rank

Total Posts: 4

Joined 2020-02-05

PM

I can't find sensor in compatible devices list.
I will try get data from BLE and compare with ANT.      
RankRankRankRank

Total Posts: 114

Joined 2010-10-25

PM

Some of the cheaper devices coming out of China are not following the spec correctly with regard to this. The Coospo ones were the first dodgy ones I saw. There have been others since. There are similar sorts of issues with speed and cadence sensors not counting pedal revs or wheel revs correctly. The data to display the instantaneous main value is correct so to look reasonable to start with. If your head unit / app is using the counts though for things like averages then that data will be wrong.

I actually had contact with one of the companies spamming me a sales pitch for a customized version of a sensor. I normally don't respond to this stuff but in this case they got a detailed explanation of how they were breaking the spec and along with the response that I would only be interested in a device that had passed the certification tests.      
RankRankRankRank

Total Posts: 139

Joined 2012-06-27

PM

Greyfox: Can you share what sensor you are running into issues with?      

Signature

Ian Haigh

Rank

Total Posts: 4

Joined 2020-02-05

PM

haighi - 18 February 2020 11:45 AM
Greyfox: Can you share what sensor you are running into issues with?

haighi, yes, this is Kyto Fitness KYTO2809 ANT+ and Bluetooth heart rate sensor.
Manufacturer did not help, they convince me that everything is fine.

But I solved this problem by making my custom firmware using nRF5 SDK. Now sensor works fine.
This sensor maked on nRF51422-AA chip.