bangle2 no way to calibrate the altitude

[eisengpferd]

Hello folks,
i just got two bangle2 and it ist good fun. But not so staight forward as it should be...

I would like to use the altitude reading and try to calibrate it to the correct number.

1. in "Settings, System, Altitude" should be a way to calibrate and set as default. I can not change the value of pressure or altitude because when I click on "pressure" or "altitude" the setting is only displayed for 1/2s and it is resetted after any input.
   What does the "set default" mean? If I click it the altitude is set to -43m allways.
   Where can I define the "default altitude"?
2. Seen in the wiki I should be able to calibrate the altitude within the "Altitude App". The Alt Reading in this app is very accurate. But the button is assignd to switch to the "standard altitude". When I try to leave the app to use the calibrated altitude in another app the button will first reset the altitude before it leaves the app.

Thanks
cheers /Hendrik/

[gfwilliams]

Hi! When you go to "Settings, System, Altitude" you get:

• Pressure
• Altitude
• Adjust up
• Adjust down
• Set Default

Just tap on adjust up/adjust down and each time you press the altitude will change by around 5m. When you exit the menu by pressing the button or tapping in the top left the calibration is changed.

"Set Default" just sets the pressure at sea level to 1013.25 (you can't change that - it's just the agreed definition: https://www.google.com/search?q=pressure+at+sea+level)

For "Altitude App" do you mean https://banglejs.com/apps/?id=altimeter ? Sorry about that - there were some changes to the way buttons were handled to make the Bangle more responsive and it looks like that app wasn't updated. I'll make it display a 'do you want to reset?' prompt.

[eisengpferd]

Hi Gordon, thanks for rebly.
yes this adjustment works in rough steps. Would be ok. But while changing this the "pressure" still keeps at same reading.
And there seems to be a adjust menu if I click on the text "pressure" or "altitude" but they dont work.

Yes sorry for that: I meant the app "altimeter". Yes a prompt for reset woult solve the problem as this will not effect the alt when I keep the button pressed :-)

I found another solution: In the settings of the "altimeter widged" there is also a setting where I can adjust the barometer / alt.

It would be nice to be able to adjust the "Default" because this could be used to start from in differend days when I start a walk at home and the barometer has changed.

Thanks /Hendrik/

[gfwilliams]

But while changing this the "pressure" still keeps at same reading.

Yes, that's expected. The same happens for Altimeter too.

The calibration isn't a calibration of the sensor (we just assume that the reported pressure is correct), it's just to adjust for the weather changing the air pressure at sea level and hence how we calculate altitude.

And there seems to be a adjust menu if I click on the text "pressure" or "altitude" but they dont work.

Thanks! I didn't spot that first time. I've just put a fix in for it (but there was never intended to be a menu when you tapped on the altitude/pressure, so now tapping just doesn't do anything). To set the calibration based on a specific altitude (which might be a nice addition) we'd have to do a bit of maths to work out the sea level pressure.

If you update now, those two apps should be fixed.

adjust the "Default" because this could be used to start from in differend days

Ahh, ok. I guess what you really want then is to input a 'default altitude', and for the sea level pressure to be worked out from that?

[eisengpferd]

Great thanks. Now I can use the "Altimeter app" to set the altitude. If I know the altitude of my location I can set this in. And if I know the sea level pressure of my location (from perhaps some meteo service or from a calibrated barometer) I can set this in and the result will be the same.

What I mean with the default altitude: Just imagine evey weekend you want to start a bycicle tour from your home and want to mesure the altitude correctly. If you know your high of your home it could be "default" and with one click in the "altimeter app" the correct alt could be set every time you start a ride at home.
For me it would make sense to write in the "default high" in the settings app so I could use it in other apps (altimeter)

From other gadgeds I know the mesurement of "altitude gain" up or down. For that I did post an issue for the app "gps trekking".
https://github.com/espruino/BangleApps/issues/3887 but this is perhaps not your code :-/

thanks /Hendrik/

[gfwilliams]

Yes, the GPS Trekking app isn't something I worked on - but as you say favouring the barometer over GPS altitude is probably more sensible.

Makes sense about the default - being able to configure the default sea level pressure I don't think is useful, but being able to set a height and have Bangle.js work out sea level pressure would be cool.

Doing so would mean reversing this formula: https://github.com/espruino/Espruino/blob/master/libs/banglejs/jswrap_bangle.c#L5265

I'm not sure when/if it's something I'd get around to, but if you or someone else wanted to look into it, it'd be pretty neat.

[eisengpferd]

but I am doing exactly this: In the altimeter app I can adjust the high or the sea-level-pressure because they are changing at the same time.
So this code could be useful to use even in the settings app.
Or just let the altimeter app set in the default high/sl-pressure.

Sorry, I did very little coding with a Seeduino in C++ with much help of a friend. I have never coded in JS...
But I like to test settings and apps so I can help in this way.

[eisengpferd]

(just bringing the thread back to live after account ban)