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Author Topic: Why do sliding doors not open, at first attempt, when I approach them?  (Read 3150 times)

Tebele Molata

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Tebele Molata  asked the Naked Scientists:
   
Hi

Why do the sliding doors not open, at first attempt, when I approach them?
 
Regards,
 
Tebele Molata

What do you think?
« Last Edit: 05/12/2010 14:30:05 by _system »


 

Offline Don_1

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I presume you are talking about PIR activated automatic doors, in which case are you a Size Zero
 

Offline RD

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I presume you are talking about PIR activated automatic doors, in which case are you a Size Zero

or well insulated, or in a hot country, (i.e. your exterior is a similar temperature to your environment).
« Last Edit: 06/12/2010 20:34:42 by RD »
 

Offline techmind

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If it's PIR then the sensitivity does depend on your external temperature being recognisably warmer than the environment.
If you're in skimpy clothing and the ambient temperature is near 37C, you'll be near-invisible to that technology.
Or if it's cold and snowy, you're wrapped up in a thick coat and hat and boots and have been outside long enough for the outside of your clothes to have reached equilibrium with the outdoors then you'll also be fairly invisible.
If you have a small size (or are a child) it only makes things worse.

Whether it's PIR or microwave Doppler radar (less common these days, but still used) the direction and speed at which you approach the door can also be a factor. Experience shows that if you approach at a glancing angle then this reduces your chances of being detected - so the door is more likely to fail to open.
 

Offline Geezer

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Does any of this explain why I frequently become invisible in retail establishments and restaurants?
 

Offline CliffordK

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They open just fine...

You just have to run fast enough  ;D

When I was a kid,
We were picking walnuts at a friend's house.
I went into the house to go the the bathroom and left the door open.
When i cam out of the bathroom, someone had closed the door...  needless to say I cam running through the door full speed ahead.   :o

It made a nice hole right through the middle of the door.  [B)]  As far as I know, I was unhurt.

If you are talking about a sensor-thing in a store.

There are a few different kinds of sensors in common use.
    Weight sensor under a mat.
    Motion sensor.
    IR/heat sensor.

If it is a motion sensor, it may depend on the direction you approach.
Perhaps wave at it. 

Are you "short"?
Is it only one store?  I always have the other issue that the doors open when I'm not intending to exit.

 

Offline Don_1

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Being slightly on the large side (eh em), I have the opposite problem, when I go to the high street, all the stores doors open in unison, even those at the opposite end of the street to where I am.
 

Offline Don_1

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Does any of this explain why I frequently become invisible in retail establishments and restaurants?

Try waving a few $1000 bills in the air. This usually attracts the attention, unless its a Monday morning ('What I did over the weekend' far more important) or the day after a much hyped episode of some p***y soap opera, or the sales assistants (sorry, should be more PC - Retail Ad visors) are all in their teens or are all women or are all men or are all old.......... Hmmmm. Problem, isn't it.
 

Offline maffsolo

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Does any of this explain why I frequently become invisible in retail establishments and restaurants?


maybe that you are recognized, as a not a hot spender of money.
 

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