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RE: [Sensors] Temperature sensor use cases

From: Josh Soref <jsoref@rim.com>
Date: Tue, 26 Jul 2011 18:51:53 -0400
To: "Tran, Dzung D" <dzung.d.tran@intel.com>, "public-device-apis@w3.org" <public-device-apis@w3.org>
Message-ID: <6A252AE18765C3468EF06946F24F0B571FFCAE5D59@XCH102CNC.rim.net>
> Temperature Sensor
> 
> Use-Cases
> 
> Application can throttle activity based on device temperature.
> 
> A web application can take device temperature into account in order to
> throttle activity and avoid degraded performance or crashes due to heat
> from intense hardware use. For example, some devices include RFID
> radios with >1 watt power amplifiers and can generate a lot of heat.

Overheating is something the device needs to handle on its own. This isn't a good reason to expose temperature to web apps, potentially some might choose to actively *try* to cause the system to overheat.

General information about wanting to use less power can be reflected by the battery indicator claiming to be running down faster (which will probably be true anyway).

> Throttling performance may avoid degradation or crashes on these
> devices. In addition the application may present the user with a
> notification about device temperature and suggest an action

The system will need to do this anyway and shouldn't be relying on a web application (which will probably fail under interesting cases anyway). In fact, deployed devices already do this (the last products I shipped certainly did, I know, I rewrote the translations for them).

> or send a notification to an IT web service that indicates the
> device is "running hot".

While a widget might want to exist for this purpose, I really don't think this justifies a Web facing API. It's a use case for SNMP and if the device wants to support SNMP, it can and should.

This should really be SNMP/nagios (or an equivalent).

> A weather monitoring application uses temperature data from automobile
> temperature sensors.

This is more reasonable, and probably supports a path via Discovery (with pairing to applications) of Sensors.

> A web application that runs on a dashboard console could send the
> temperature outside the car, with additional location information to a
> weather related web service.

This is the same use case as the previous one.

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Received on Tuesday, 26 July 2011 22:52:21 GMT

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