Uncaught InternalError: Timeout (Magnetometer)

[espruino-discuss]

Posted at 2017-05-10 by badryan

I'm using the magOn event to report magnetometer readings. As shown in the example for the Door Controlled Light, I defined a global variable zero and calibrate the sensor with the readings of an initial Puck.mag() call. However, when I try and use Puck.mag() out of the convenience of a setWatch function upon a button press, I get the above error message.

Can anyone tell me what's wrong here?

setWatch(function() {
  zero = Puck.mag()
}, BTN, {edge:"rising", debounce:50, repeat:true});

and I receive something like

Uncaught InternalError: Timeout (Magnetometer)
 at line 9 col 12
  Puck.mag();
           ^
in function called from system

[gfwilliams]

Posted at 2017-05-10 by @gfwilliams

Are you using up to date (1v92) firmware?

Also, the only time I've come across this before has been when the battery is almost flat - the main processor works fine but the magnetometer stops working slightly before the ARM has trouble.

Please could you check Puck.getBatteryPercentage() just to make sure?

[espruino-discuss]

Posted at 2017-05-10 by badryan

Says 1v88. Battery level is shown as 100, but I know that can't be true.

Is there a video for firmware updates using iOS? Watched the Android one, but the iOS app looks quite different.

[espruino-discuss]

Posted at 2017-05-10 by badryan

Upgraded to 1v92. That fixed it.

[gfwilliams]

Posted at 2017-05-10 by @gfwilliams

Great! I'm afraid there isn't a video for iOS - I'll make a note to create one.

[espruino-discuss]

Posted at 2019-08-07 by user101989

I reproduced this behavior with a flat battery showing 0 or 10 with E.getBattery(), not sure why the oscillation, but the magnetometer failed to record even though other components were still functional. Changing to a new battery brought the magnetometer back to life. firmware 1.99

[espruino-discuss]

Posted at 2019-08-07 by Robin

Wed 2019.08.07

'not sure why the oscillation'

Basic physics, based on lack of sufficient voltage supplied.

See p.17 nominal voltage is 3v - device unpredictable below that level, especially the AD as it's readings are ratio-metric based on voltage reference

https://www.espruino.com/datasheets/nRF52832_PS_v1.0.pdf

See 'Continuous Discharge Characteristics' graph in datasheet:

http://data.energizer.com/pdfs/cr2032.pdf

 
For this battery type, once voltage starts to fall off, functionality goes quickly.

https://www.espruino.com/Reference#l_E_getBattery
"Note: this is an estimation only, based on battery voltage."

The calculation

https://github.com/espruino/Espruino/blob/master/src/jswrap_espruino.c#L1745

Other discussions but for different board:

http://forum.espruino.com/comments/14517894/

[espruino-discuss]

Posted at 2019-08-07 by user101989

Thanks for the info! Ill read up, i suck at basic physics

[gfwilliams]

Posted at 2019-08-08 by @gfwilliams

Thanks for letting us know! I'll add a note to the docs.

By the time the magnetometer fails the battery is almost completely dead - it just happens that the microcontroller is a little better at eeking out the final few percent than the magnetometer is!