Accelerometer question

Michael 'Mickey' Lauer mickey at
Fri Oct 10 15:24:58 CEST 2008

Am Freitag, den 10.10.2008, 00:55 -0400 schrieb Joel Newkirk:
> AFAIK by default they're always powered up.  Certainly apart from the times
> I hit 'dead accelerometers' that took a few reflashes to get going again,
> I've never had to power them up unless I'd previously powered down.

They're only consuming energy once someone has the device nodes open.

> According to the datasheet at
> Symbol Parameter Test         conditions         Min.Max.Unit
>   Idd  Supply current         T = 25°C, ODR=100Hz 0.3 0.4 mA
> IddPdn Current consumption in T = 25°C             1   5  μA
>        power-down mode
> So the power draw is pretty low, both together being less than one
> milliamp.
> I suspect that frameworkd will be able to shut them down automatically if
> nothing needs them, once accel support is incorporated.  (IIRC it does that
> now for other subsystems, like gps)

I'm still waiting for the kernel developers to enable the
wakeup-threshold. That should make it possible to shake it before it
reacts to any gesture, hence allowing to incorporate gestures everywhere
(if wanted).


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