Outdoor Recreation Archive

fēnix 5 Series Ant+ sensors disconnect at same time - Help please!

Ant+ sensors disconnect at same time - Help please!

Former Member over 6 years ago

I've recently purchased 2 sensors to track bike ridings (speed and cadence). When they work, they work fine. But, from time to time, they disconnect from my Fenix 5s and never get back to record.

The main problem is, when they disconnect, there is no way to make them work again. Only reliable way to recover is stop, pause the activity 5~10 mins in order for everything to reset/go into stand-by mode and resume/restart the activity.

I would like ideas to try and/or Garmin team to keep the investigation of the root source.

Setup: Sensors (Magene Gemini 210) are installed on front wheel hub (speed) and left cranckarm (cadence). I use the watch on the left hand, so distance to sensors is <1m (<3 foot). Fenix 5s is on latest production firmware (12.3 / Sensor hub 6.25) and there are no 3rd party watch faces or apps installed that could interfere the watch processor.

Tests executed so far:

1.- Ability to connect in distance: ~6m (~20 foot), both sensors connected fine and worked in a controlled environment (no real ride).
2.- Sensor battery replacement. Before and after the battery swap, Garmin reported sensor battery to be OK (checked through the 'About' menu option, within each sensor configuration options).
3.- Disabled 'auto-pause' feature from my bike activity setup. -This helped a lot to improve reliability-.

I' ve also searched internet and seems to be a common problem across Garmin (try to search: "ant+ sensors disconnect at same time site:forums.garmin.com") and in general (try to search: "ant+ sensors disconnect at same time").

I do not ride with my mobile phone, so the only devices connected to my Fenix 5s are these Ant+ sensors,

So far, my guess of the reason for disconnection, 'as a user' without tech knowledge on how Ant+ connectivity works, are:

a.- A process within Fenix that drops sensor readings. -> if this were the reason, some more work on the sensor hub firmware design could help.
b.- Environment radio interference. -> nothing that any vendor can do here except for improving their firmware design to recover more rapidly.
c.- A certain time-out on activity recording that triggers the disconnection (e.g. stop pedaling for a while in a terrain descent). -> this may explain cadence disconnection but not bot sensors at the same time, I guess.

Since I've not been able to reproduce the issue repeatably, it seems to be of random occurrence, but I do not believe that to be the case, and truly believe that we have to provide Garmin team the most information we can collectively can in order for them to be able to figure out what is going on and, hopefully, help us with a fix.

Thank you all in advance for any input/suggestion.

Cheers!.

Top Replies

George over 6 years ago +1

Temp disconnecting is "normal"

Oh come off it. Yes, I understand that it might default to internal sensors in the case that an external one is out-of-range but it happening repeatedly at the same…

All Replies

0 Former Member over 6 years ago

Hi OnlyTwo, can you see this activity? (Sensors disconnect at 3'47", previous cadence readings in 0 are OK): https://connect.garmin.com/modern/activity/3348070440?share_unique_id=2

This is the usual behaviour when disconnection happens. Actually, I tend to believe it is somehow related to an interference, since the disconnection use to happen around the same geographical spot.

I was thinking that, if there is no way around, at least we should have an option and/or key shortcut to turn off sensors in order to avoid data loss on tracked activity (to speed up the process while riding). In my case, when the speed sensor is lost, tracking of speed and distance is lost (i mean, even though GPS data is there though, the information can not be seen in GC).

In regard to your BLE comment, how do you do that? I don't find any menu option for that. Also, I have reinstalled the sensors with new batteries, I do not believe that to be the reason for disconnections .

Thanks!

0 TrippyZ over 6 years ago

The problem is caused by electrical interference from the train tracks. A quick stop and start of the activity should cause them to reconnect.

0 Former Member over 6 years ago

Thanks for the feedback and apologize for the delay on my side (I've never cared about .fit files to be honest, and needed some time to figure out which one would apply to that activity).

OnlyTwo , find attached the fit file of that activity... I'll try to dig into how to read these files for clues. In regard to ANT+ and BLE, I've not been able to find how to connect these sensors as BLE. When they are detected, only ANT+ option is available. I've not found a way -within the watch menu- a way to force 'only connect sensors with BLE' (which is supported by the sensors in theory).

TrippyZ , train tracks well could be, also thought it could be related to a sort of Police cabin that is also around that geo spot.

The problem is, when the disconnection happens it is not that 'quick' to re-establish the reading.

What I noted on the watch after the drop of data:

1.- Sensor status says' connected', but there is no info on the watch from them (I've created a data field screen with Speed & Cadence information to monitor their information).
2.- A quick stop/resume of the activity does not fix the issue.
3.- 'I guess', since the sensor status is 'connected', speed data is not switched automatically to GPS unfortunately. Only way to achieve this 'on the fly' is to go into the menu/settings/sensors/speed/and switch to 'off' (too many key inputs required while riding... not safe, trust me :) ).
4.- For everything to get back to normal, without any interversion, I've found that I need to pause the activity, wait for everything to go into stand by status (5 mins+) and resume the activity.

That is why, I was thinking that it may help if garmin enables a sort of 'sensor reset' option to re-connect everything from zero on the fly.

Thanks again for your support!.

0 Former Member over 6 years ago

Told you OnlyTwo , never cared about fit files :). I believe I downloaded the previous one from the wrong directory (garmin/monitor instead of garmin/activity).

Try this one. With GPXSee I can see that speed (from GPS) works but Cadence drops to zero.

What tool do you use to view the data?.

thanks!

0 Former Member over 6 years ago

OnlyTwo thanks for reviewing , I need to learn to use fit files :)

Interesting if sensors are sending zeros. In the watch they appear as connected -right after the disconnection-, perhaps the interference in that spot makes them crazy and they need to go into stand-by mode themselves to recover.

0 George over 6 years ago

Just because zeros are recorded it doesn't mean that this is what the devices are sending. I have a similar problem on a 645m which sometimes breaks the Bluetooth headphone and Ant+ sensor connections at the same time (especially when running under a particular railway bridge but sometimes for no apparent reason). The only reliable way I've found to recover is to reboot the watch. What's needed is a reset connections options in the setup menu so you can do this without stopping the activity.

0 Former Member over 6 years ago

George , in my case, I've tried:
watch reboot;
activity pause-resume;
with activity still running, turn off and on each sensor
wait <2 mins and restart
none of these fixes the issue.

In my case, it seems I need to wait for sensors to go into stand by mode (~5 mins) and then re-connect (no need to do anything special on watch, just pause the activity so when it resumes, everything is synchronized from scratch).

OnlyTwo , I'm currently on watch firmware 12.4 and sensor hub 6.25. The sample activity had firmware v12.3 and sensor hub 6.25. This is the link to Connect Web https://connect.garmin.com/modern/activity/3348070440

Cheers!

0 Funracerr over 6 years ago

Hello.
Yesterday I had a similar issue with my Garmin 935. I was riding indoor and after ~1 hour the power, cadence, speed and also heartrate did not show any value. Sometimes it showed 0 or even two dashes ( -- ). This behaviour was intermittend. It can be clearly shown in the result on Garmin connect. (see Photos)
I never had this problem before. There was a recent software update. Maybe there is something funny.
Attached is the .fit file.
Help is appreciated!
Cheers
Volkerciq.forums.garmin.com/.../1454707.gif

0 George over 6 years ago

OnlyTwo here is the sample run. Let me know if you need the actual FIT files and I will see if I can work out how to find these.
[FONT=helvetica neue]connect.garmin.com/.../3384352539 [/FONT]

You can see the Tempe disconnecting at about 18 minutes in (where the temperature jumps up for about 1 minute). I'm running with a 645m firmware 4.20 plus a Tempe (no version) and Trekz Air headphones.

CesarF5s I had a similar experience to you.
The headphones disconnected at about the same time as the Tempe but on this occasion I was able to reconnect them a few minutes later.

0 George over 6 years ago

Temp disconnecting is "normal"

Oh come off it. Yes, I understand that it might default to internal sensors in the case that an external one is out-of-range but it happening repeatedly at the same time as losing other sensors or the headphones is too much of a coincidence. It seems much more likely that this is simply a bug; the internal Garmin driver is hanging when it receives corrupted data (caused by EM interference).

OnlyTwo FIT file attached with compliments.