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Re: DeviceMotion event vs Accelerometer sensor data

From: JOSE MANUEL CANTERA FONSECA <jmcf@tid.es>
Date: Thu, 27 Oct 2011 10:50:32 +0200
To: Lars Erik Bolstad <lbolstad@opera.com>
Cc: "public-geolocation@w3.org" <public-geolocation@w3.org>, Steve Block <steveblock@google.com>, Andrei Popescu <andreip@google.com>, "public-device-apis@w3.org" <public-device-apis@w3.org>
Message-id: <CACEE7CB.1CA36%jmcf@tid.es>
Thanks for your advice. We will rename those interfaces and make
clarifications on the spec in order not to confuse authors.

best

El 17/10/11 11:13, "Lars Erik Bolstad" <lbolstad@opera.com> escribió:

>Hi Jose,
>
>There is as you say a subtle difference between the two proposed specs
>and I guess that fact could be confusing to developers, especially since
>the interfaces have the same names (e.g. DeviceAcceleration,
>DeviceRotationRate) but give different values (smoothed vs. raw).
>Maybe you could consider renaming the Sensor API interfaces to make it
>more clear that they expose raw sensor data?
>
>Best regards,
>Lars Erik
>
>
>On 06.10.2011 14:03, JOSE MANUEL CANTERA FONSECA wrote:
>> Dear GeoLoc WG,
>>
>> My name is Jose Cantera and I'm one of the editors of the Sensor API [1]
>> within the Device APIs WG.The purpose of the Sensor API is to provide
>> access to the raw data provided by sensors accessible from a device. We
>> have had within the Working Group different discussions whether the
>>Sensor
>> API should address Acceleremoter and Gyroscope sensors or not, due to
>> potential overlapping problems with your DeviceMotion events spec.
>>
>> DeviceOrientation says "The information provided by the events
>> is not raw sensor data, but rather high-level data which is agnostic to
>> the underlying source of information." but our Sensor API is intended to
>> provide raw sensor data. In theory there is a subtle difference between
>> the two. The article at [2] gives a good explanation on the difference
>> between raw sensor data and smoothed data coming from the accelerometer.
>>
>> Another important point to take into account is that in the Device
>>Motion
>> event spec there is no way for an author to specify the delivery rate
>>for
>> sensor data. And that is something well covered by the sensor API.
>>
>> Thus the question for you is how do you see this problem?
>>
>> Should the sensor API target Accelerometer and Gyroscope?
>>
>> How we can coordinate? Can we have different APIs for different use
>>cases
>> and share data structures for example?
>>
>> Many thanks, All the best
>>
>> [1] http://dev.w3.org/2009/dap/system-info/Sensors.html
>> [2]
>>
>>http://windowsteamblog.com/windows_phone/b/wpdev/archive/2010/09/08/using
>>-t
>> he-accelerometer-on-windows-phone-7.aspx
>>
>>
>>
>>
>>
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Received on Thursday, 27 October 2011 08:50:54 GMT

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