@Lee_Nover: indeed I can see the HR calculated by the HxM is not very reliable I have made some tests with my software where I use the RR to calculate the HR (HR=60000/RR, RR being in milliseconds) and there there is nearly no drop or maybe 2 -3 seconds max, and those can be filtered out. when I compare this HR based on RR with my Garmin HR values it is consistent (yes I wear both Garmin and HxM belt during my tests).
ok, your findings are very usefull, so we can exclude the skin contact as the reason of the issue.
in the meantime I also made some tests where I calculate the HR using the RR values that you receive from the HxM.
and when using the RR and some filtering (that needs to be further validated) I don't have the drop but I need to make more tests.
Yes it is a problem with the HxM not with RunGPS, I can confirm that since with my program I have access to the packets received from the HxM.
I have already sent my findings to Zephyr with the packets traces received from the HxM to prove it. this was friday, so hopefully next weeks I should have some answers from the analysis of their engineer.
10.01.2010 19:24:55 UTCgeändert am 10.01.2010 19:33:14 UTC
Problem with HxM, not with contact to the skin
Just did an long test.
http://www.gps-sport.net/home/Rouven/trainings201001/100110_181810_744290/training.html
The problem with the "lock" is not an problem with the contact to the skin!
I used my electrodes with the wire to the HxM, so i really have perfect skin contact.
Traininglog:
0 - 40min = just sitting at the desk and working. (no problem at all)
40min ...
then i did some sprints.
everytime, really eveytime it "lockes" and then go up to the right value.
You see it on the last 5 peaks!
-> lock, raise ....... lock, raise ..... lock, raise ....
If you raise your heartrate to fast, the HxM need some time to react on this fast change!
gmngueko you said that with your test program you got the same error,
so its definitely an problem with the HxM itself and not with Run.GPS right?
But why this problem occure?
This is an log of my run.
http://www.gps-sport.net/trainings/running_213256
And there is the same (now figured out) problem. I started to run....the heartfreq. raises fast and it "locks"
Then after a while there are no fast/huge changes so it works perfekt....
I´m a little bit happy that i figured out the problem now!
Can someone confirm this "lock" problem on his own training logs?
That would be nice to see, perhaps its just an fault on my device...
10.01.2010 17:40:48 UTCgeändert am 10.01.2010 18:33:30 UTC
Thanks for the idea! Just made the first prototype.
With this you have a very good connection to the skin,
because of the electrodes. But its not so good to wear..
I need to check if the cadence is right, if i put the HxM into the bag of my HD2.
Perhaps i have the time tomorrow.
With the electrodes and the wires its a better feeling than with the new prototype.
EDIT:
It would be nice to disable the cadence.
The smaler version of the HxM dont have the cadence.
I always use GPS in the outside, so the cadence is not that important.
Than i could put the HxM in the pocket without any problem.
EDIT2:
The HxM really need to be vertical to work propperly.
Just checked it!
I'am not sure about the cadence, but my understanding was that the cadence was calculated using the vertical acceleration mostly. But actually you can try and see what is the result.
Your solution is very interesting BUT it will most likely kill the speed and distance calculation like for the cadence, but it will be very interesting to actually make a test to see what is the exact behavior.
will it be possible to use the EKG electrode in place of the original belt ? meaning the HxM will actually be hold in place by the EKG electrodes which would be holding on your chest ?