Re: Sensors for doors & windows & ...

[Chris Hunter <cjhunter@xxxxxxxxxxxx>]

Gerry's boards ... presumably as in :

http://www.rgbled.org/maxbotix/index.html

up to twelve sensors per board sounds pretty useful !

our PC has four RS232 sockets, one maybe two being spare ... so could
be good for us, too (assuming I can link to Cortex) ... !


Chris


On 27 Oct 2007, at 12:23, Kevin Hawkins wrote:

> I'm intending using some of the Maxbotix ultrasonic sensors pointing
> slightly diagonally across the doorways.  These then provide a
> direction
> indication for a person moving into or out of a room  (short to
> long or
> long to short reading) and based on distance you can elimate outside
> false trips.  I use Gerrys boards, only played so far but seems
> viable,
> fortunately I have deep doorways in walls often 3 foot thick. .   A
> top
> mount sensor might even identify people based on height- or the dog .
>
> I also have some Pulsor -strain sensors arriving any day now - which I
> hope to use on the stairs and a couple of doorways.
>
>      K
>
> Chris Hunter wrote:
>>
>>
>> 'thinking of sensors for doors & windows ... and the
limitations of
>> the reed-switch (just open or closed & no certainty on what
it's
>> telling about the door, unless perhaps it's attached to the
locking
>> mechanism in some way - which can't see how to do as a retro-fit)
...
>> was trying to think how else ... strain-gauge ... laser + mirror
...
>> all have just-as-bad limitations ... hmmm ...
>>
>> 'wonder if PIRs are all the same ... obviously not, but in the
sense
>> of being designed to pick-up just movement .... are there some
that
>> are designed to pick-up position, say, or presence not associated
>> with movement, or movement of hard but not soft objects, or ... ?
>>
>> with MHVR, having doors or windows open might be expected to
affect
>> the pressure in the house ... so, all closed => some
pressurisation,
>> maybe, depending on the relative speeds of the inlet & outlet
>> fans ... 'wonder if adding air-pressure-sensor(s) to each room
could
>> be useful ... picking-up both level & fluctuations ... and so
doors
>> open, people moving-about, curtains wafting, pesky flies,
>> whatever ...
>>
>> micro-phones are air-pressure sensors, of course ... wonder if a
>> broad or limited bandwidth one would be best ...
>>
>> hmmm ... would fuzzy logic be the thing, to make it work ...
looked-
>> up Wiki, but 'am really none the wiser, 'though it did mention
>> pattern recognition as being an application for it ...
>>
>> rambling, sorry, but I feel there's a glimmer here !
>>
>> or maybe I'm clutching at straws ...
>>
>> Chris
>>
>>
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