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Turning off source switching.

milesnz
5 months ago

I have noticed that the ability to turn off HR source switching does not always work.

I have source switching turned off on my watch because I trust my HR strap to give a more accurate reading and do not want my watch to switch to optical HR during an activity.

To test this feature I wore my HR chest strap during an activity and verified that the watch was recording data from the strap. All good.

I then removed my HR strap and noticed HR on watch disappeared as expected. 

However the watch LED's then came on and started displaying optical HR.

Isn't this not supposed to happen if I switch off HR source switching.

Edit.

It has now occurred to me that taking off the chest strap will in effect turn it self off, thus loosing connection with the watch. The watch Optical HR will then take over.

As long as there is a connection between chest strap and watch then the watch optical HR will NOT take over.

I repeated a similar experiment with a external optical arm strap, If I turned it off, the watch optical Heart rate took over.

If I just removed it from my arm and maintained a connection with the watch, the watch optical HR did NOT take over.

If  this is how it it supposed to work, I can see the logic in it.

Can anyone else confirm these findings.?

  • 0 5 months ago

    Here's Garmin's official explanation:

    [https://support.garmin.com/en-US/?faq=Nf8r6ApX4d9lX0G0flEsVA]

    Heart rate dynamic source switching aims to provide the most accurate heart rate possible by dynamically selecting the best source of heart rate data when when wearing a compatible Garmin heart rate monitor strap with a compatible Garmin watch.

    What Garmin Products Are Compatible With This Feature?

    Any Garmin® HRM strap and compatible watch from the list below can do basic heart rate source switching when a heart rate monitor is unavailable (for example, if there is a drop in connection). Switching sources based on the quality of the heart rate signal during an activity requires the use of a Garmin HRM-FitTm, HRM-ProTm, or HRM-Pro PlusTm heart rate monitor along with a watch from the compatible watch list below.

    How Does Heart Rate Dynamic Source Switching Work?

    Dynamic source switching is available for all activity types to provide seamless heart rate data if the heart rate strap becomes unavailable. The biggest benefit of the feature is for running activities. A heart rate strap is usually the most accurate source of heart rate data for running but occasionally there can be inaccurate heart rate at the beginning of runs, often referred to as start-up noise.  This is caused by poor connection between the skin and the electrodes and typically resolves once you start to sweat. With dynamic source switching, when a heart rate strap detects low signal quality, heart rate from the optical heart rate sensor on the watch is displayed and logged instead. The heart rate strap remains connected to the watch and the heart rate source will automatically switch back to the strap once the signal quality improves.

  • 0 4 months ago in reply to FlowState

    With my 955 I don't have this option => Select Source Switching

    It seems your link is not for the 955.

  • 0 4 months ago in reply to PJohann

    I think it has to be disabled like this:

    Settings -> Health and Wellness -> Wrist Heart Rate -> Source Switching (on/off)

  • 0 4 months ago in reply to FlipStone

    Yes, but I dont have this option.

    Only Status, While Swimming, Abonrmal HR Alerts and Broadcast HR ( to start it)

    My FW is 19.18 

    Bizarre

  • 0 4 months ago in reply to PJohann

    My link is for 955, it works just as FlipStone described it. I have firmware 19.18

    I don’t know why the dynamic “product compatibility checker” in your screenshot doesn’t work (but it’s not surprising for Garmin tbh). However, 955 is on the compatible watches list on the same page.

    I’ll guess that the reason you’re not seeing it is you don’t have an HRM paired to your watch. Someone else mentioned this in another thread, and it’s right in the support article:

    Can I Turn Off Dynamic Source Switching?

    Disabling this feature requires for you to not be in a activity profile and have a heart rate monitor strap as a paired sensor to the watch.

  • 0 2 months ago in reply to FlipStone

    Got it, and mine greyed out: cannot toggle it. 255 Music. WTF? I'm on 20.21 Beta

  • 0 2 months ago in reply to Sir Rasor

    Looks like they changed the behavior: previously you could toggle source switching if an external HRM has been paired, but now you can only toggle it if an external HRM is *currently connected*.

    Someone posted a bug report: forums.garmin.com/.../source-switching-option-gone

  • 0 2 months ago in reply to FlowState

    Okay I figured it out. I must enable automatic searching for external sensors AND connect one. After that the toggle works and after that I can disable automatic searching too. Weird :)