Problems with BLE speed sensor, Locus 3.18.6+

Tirfo shared this problem 5 years ago


I have used a Wahoo Speed Sensor on my bike since a couple of weeks. I have made 3 observations which are most likely not (!) connected to each other. Maybe you find them interesting, too.

1) Especially at lower speed, the speed sensor value in the dashboard drops to 0 frequently. By contrast, the track chart as well as the gpx export are fine, there are no "0" values. It seems that Locus caluculates speed differently for dashboard.

2) Sometimes, but not always, when the connection to speed sensor has just been established there is a spike of >>100 km/h in the chart. Due to this outlier, the scaling of the y-axis is way too high for the rest of the speed values. Could this be prevented somehow?

3) In the chart, there are gaps for "speed" from sensor. These gaps do not corellate with "0" values in the dashboard (see 1) and they do appear also at high speed. In the gpx export the whole line for the speed extension (<gpxtpx:speed>...) is missing for the respective track point. Surprisingly, there is a value in the csv export. Do you have an explanation?


Replies (2)


Good day Tirfo,

I've moved your post to separate topic, not to mess old topic too much with something, not directly connected.

Thank you for your observation. These all are connected to sensor that provide such data - inaccurate, with gaps etc. Locus currently do not do any optimizations or filtering of speed values from sensor. Seems it will be needed ...

I'll need to measure some own sensor values and use them for testing, so I'll let you know later. If my sensor will work correctly (to be true, I never attached speed sensor to my bike for real field testing), I'll ask you for a log with special version, that will print out some data.

Meanwhile just for your infoomation:

1) values in chart are speed values - if there is sensor speed, it is used if not is used speed from GPS. Anyway "sensor speed" in dashboard should be same as speed exported to GPX 1.1. Interesting

2) yep, some filtering is needed here

3) speed in <gpxtpx:speed> is always speed from sensor, speed in csv is same as in case 1), so "sensor" if available, otherwise GPS


Hello Tirfo,

very old topic. If you still use the Locus Map app, give it a try to the latest Locus Map 4 version. I believe that the problem will be solved there. Otherwise, feel free to write me and I'll look at it closer.

Jiří M. aka Menion

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