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Re: [sensors] Device Proximity (was: Device light and proximity sensor)

From: Marcos Caceres <w3c@marcosc.com>
Date: Thu, 10 May 2012 10:19:45 +0100
To: public-device-apis@w3.org
Message-ID: <B92C8D6501914E25821AB0E639E4946D@marcosc.com>
On Thursday, 10 May 2012 at 06:04, N.V.Balaji wrote:
> Just reporting the value is a better approach. Even though you may trust the
> people closer to OS, you can't guarantee all implementers agreeing on the
> same values.

Again, this only comes down to the use case and the variance between them. Remember that other things can cause variance in the reading too (e.g., transparent plastic in front of the infrared beam, as iPhone users learned: http://www.youtube.com/watch?v=3tGqQd7S7d8). For other types of proximity sensors, there is also other sources of variance simply based on the type of material (this is by design: http://www.fargocontrols.com/sensors.html ).  
 

So, can we please get some agreement on the use case(s) and requirements? If the use case is "phone next to ear", then a variance of a few centimetres or millimetres won't matter. If the use case is more industrial, like "detect when metal gear spoke spinning at 200rpm comes into 2mm proximity to the sensor", then current model would be better. However, we still need to consider that higher sensitivity proximity sensors might be part of an array of sensors (i.e., car parking sensors). See this proximity sensor array as an extreme example: 
http://www.youtube.com/watch?feature=endscreen&NR=1&v=vzWEgOt3xsM

See also the following, which also contains good details about proximity sensors: 
http://www.omron.com.au/technical_guide/proximity_sensor/index.asp 




-- 
Marcos Caceres
http://datadriven.com.au
Received on Thursday, 10 May 2012 09:20:30 GMT

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