Re: Sensors for doors & windows & ...

[Chris Hunter <cjhunter@xxxxxxxxxxxx>]

'wonder if something like this would be better than a potentiometer -

http://www.usdigital.com/products/s4/

with the string-approach, that is ...

Chris


On 28 Oct 2007, at 12:02, Chris Hunter wrote:

> 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
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