Re: Sensors for doors & windows & ...

[Chris Hunter <cjhunter@xxxxxxxxxxxx>]

going a bit further ... maybe a string run between a point on the
door & spring-unit in the frame (or the other way around), to keep
the string in-tension, would work, the string being wound-around a
potentiometer at some point between the two ends ... with an
additional pulley, the spring & the potentiometer could be hidden in
the frame, or the door ...

a linear slider potentiometer might be an alternative ...

not sure about duty-cycle ...

hmm, could be worth an experiment ...

Chris


On 28 Oct 2007, at 11:41, Paul Gordon wrote:

> I'd already thought of the very same idea, however, I'd rather thought
> the hidden variety would be preferable.. You may have seen the hidden
> type, - it usually consists of a spring box which gets mounted in the
> door frame on the hinge side, and a tensioned chain issues forth &
> attaches to the hinge-side of the door.
>
> When the door is closed, no part of the mechanism is visible, - much
> better for a domestic environment, where I can't really imagine many
> SWMBO's being too happy with the rather industrial type shown in the
> picture...
>
> Again, I would imagine it shouldn't be beyond the wit of man to
> enhance
> this design to sense how much of the chain is fed out, which
> equates to
> how open the door is...
>
> Paul G.
>
>
>
> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of Rob Iles
> Sent: 27 October 2007 20:55
> To: UKHA Group
> Subject: Re: [ukha_d] Sensors for doors & windows & ...
>
> How about - - for doors, and non-sash (sliding) windows --- how
> about a
> pivoted arm and a potentiometer?
>
> I'm thinking of something similar to the "soft-close"
mechanisms you
> often
> find on doors in commercial premises - which consists of a box screwed
> to
> the door (hing side) - and two arms, hinged in the middle. the
> mechanism
> (spring?) inside the box cause the door to close when you let go.
> (hopefully, by now, you all know what I'm talking about!) :)
>
> a picture may help - - http://tinyurl.com/yok7h4
>
>
> well, if you replace the spring/tension mechanism with a
> potentiometer -
> you'd get an analogue reading of door position. feed into an A-D
> Converter,
> and with a little calibration, you could measure the exact angle /
> amount by
> which the door is open.
>
> The commercial products are quite bulky, and might not fit into your
> home
> decor (decreased SOAF) - - but they're the size they are as they
> need to
> apply considerable torque to close the door (due to the location of
> the
> mountings).
>
> You could probably build something significantly smaller, as the two
> arms
> only need to turn a potentiometer - mount it in a discreet box, and
> away
> you
> go :)
>
> If you think this is a fantastic idea, then I hereby claim - in
> public -
> all
> IP rights/copyright/patent pending ;) .....and may (seriously)
> consider
> having some made!
>
> Thoughts?
>
> Rob
>
>
> On 10/27/07, Chris Hunter <cjhunter@xxxxxxx> wrote:
>>
>>   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