GPS speed from Android/Gadgetbridge in m/s

[espruino-discuss2]

Posted at 2023-11-29 by flaparoo

Hi fellow Banglers

While working on an app which also displays the current speed, I've noticed that the read-out was wrong when using the "Overwrite GPS" function of the Android integration. I'm not a Java expert, but as far as I can tell, the code in Gadgetbride (app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/banglejs/BangleJSDeviceSupport.java) forwards the Android location.getSpeed() unchanged. According to the Android SDK, that's in "meters per second" - so, not what the Bangle API should return (ie. kph).

I think the correct fix (speed * 3.6) should be done in Gadgetbridge. Alternatively, the Bangle android app could do the same. Thoughts?

BTW I'm new to Bangle coding. The watch is brilliant!

[espruino-discuss2]

Posted at 2023-11-29 by @gfwilliams

Hi! Thanks for tracking this down, that's a huge help!

I think you're right - it's nicer to put it in Gadgetbridge so all the GPS structs on the Bangle have speed in the same format.

I've just put a fix into Gadgetbridge, so it should be in the next nightly build (or next time I update the play store)

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Posted at 2023-11-30 by flaparoo

Thanks Gordon!
I'll wait for the next F-Droid Bangle.js Gadgetbridge update.

For anybody stumbling across this post, this is my temporary work-around:

var androidOverwriteGps = false;
var androidSettings = require("Storage").readJSON("android.settings.json",1)||{};
if ('overwriteGps' in androidSettings && androidSettings.overwriteGps)
      androidOverwriteGps = true;

... [snip] ...

if (androidOverwriteGps) // speed from Android GPS is in m/s (not kph)
      fix.speed *= 3.6;