Need sensor to detect if door is locked (not just closed)
Stefan Demetrescu
door is locked (e.g. with a deadbolt), not just that it's closed?
Thanks,
Stefan Demetrescu (ste...@xenon.stanford.edu)
OrrinCharm
of microswitches mounted into door strikes that will monitor deadbolt
position. They all seem crude and expensive. I have seen a "strike
liner" in hardware stores. It's basically a plastic piece that fits
behind the strike plate. You could mount a small switch, such as an
automotive door switch, on it to monitor the bolt.
I've been meaning to try this for a long time, but it seems like a lot of
work to get it right!
Most mortise type locks are available with bolt supervision, but they're
expensive and require tricky installation.
I've also thought about using a metal sensor mounted behind the strike.
Don't know if it would work.
I've talked to many lock manufacturers at the ISC security shows about
this, and about making an electrically lockable (as opposed to releasable)
lockset. They all sounded interested, but I haven't seen any yet.
Sentrol just came out with a sliding door/window bolt with a built-in mag
contact, so maybe that's a start!
Many people seem interested in:
1. Locking all of their doors automatically when arming alarm system
2. Being able to determine if all their doors are LOCKED, not just closed.
3. Being able to open a door remotely through a keypad, phone, etc.
The third option is fairly easy, if you consider an electric strike
sufficient security and aesthetically acceptable. The other two are much
more difficult, and potentially much more useful. Sounds like a business
opportunity out there-- any takers??
* Orrin Charm *
* Charm and Imagination *
* Consultants in Home Automation *
* User Interface Design *
* Product Design and Marketing *
* Systems Integration *
* *
* 638 Camino de Los Mares #C-240-202 *
* San Clemente, CA 92673 *
* 714-366-6243 *
* FAX> 714-366-6273 <FAX *
* Orrin...@aol.com *
* Orr...@ix.netcom.com *
Fred Stuebner
>
>Has anyone ever seen a detector which can tell the alarm system that
the
>door is locked (e.g. with a deadbolt), not just that it's closed?
>
The easiest is to install a reflective photosensor in the jam, looking at
the ens of the bolt. Position it about 1/4 inch past the end (1/4 inch
gap) The sensor cannot see something too close. A suggested device is
available from Digikey, their part no QRB1114QT-ND, for $2.00, or their
ORD.....
A second approach is to insert a magnet into the end of the bolt, or
magnitise the bolt, and then place a Hall effect sensor in the jam. THis
has a difficulty in that the bolts are usually hardned, therefore
undrillable. therefore, magnetizing them may be the only option. Alegro
(formerly Sprague) make these.
-
FRED STUEBNER PJK...@prodigy.com
Mike Moss
: Has anyone ever seen a detector which can tell the alarm system that the
: door is locked (e.g. with a deadbolt), not just that it's closed?
: Thanks,
: Stefan Demetrescu (ste...@xenon.stanford.edu)
Stefan,
I have been using a switches designed for automotive alarms mounted in my
door frame behind the dead bolt quite successfully for the last 3 years.
They are very inexpensive and fairly easy to wire. The most difficult
part is placing the wire out of sight. With some forethought it was easy.
--
__
__ __ __ | |__ __
| | | | | | | __| |__| Mike Moss
| | | | | | | | __ Western Telematic, Inc.
| | | | | | | | | | 5 Sterling
| |_| |_| | | |__ | | Irvine, CA 92718
|____________| |_____| |__| (800)854-7226
Craig Dewick
>Has anyone ever seen a detector which can tell the alarm system that the
>door is locked (e.g. with a deadbolt), not just that it's closed?
No, but it wouldn't be too hard to make something to do this yourself.
You could use a simple infrared sensor with a LED and phototransistor in
the one package, position this on one side of the hole that the deadbolt
goes into so that the beam is interupted when the deadbolt is in far
enough to be deemed locked, and just have a small reflector of some sort
on the other side of the hole which, when the door is unlocked, will
reflect the IR beam back at the phototransistor of the emitter/detector.
You could put some simple logic on the output of the phototransistor to
generate a positive yes/no signal and feed this to a small micro or some
other device if the sensor needs to be hooked directly into a control
network.
The only real drawback with this method is that you need to be able to
alter the wall where the deadbolt goes in so that you can install the IR
emitter/detector and run some wires to some other electronics.
The other way to do it would be with a proximity detector, but I don't
know how they'd react with all the static metal in the faceplate over the
deadbolt hole.
Regards,
Craig.
--
Craig Dewick, located in Sydney, Australia. cde...@orb.apana.org.au
Phone: [PSTN] (int. +612, loc. 02)-527-1292, or [GSM] 0411-158-574
Always striving for a secure long-term future in an insecure short-term world
"But wait, there's more..." - "Don't send any money, we'll bill you..."
Dave Poulson
the lines already discussed. A very small microswitch (taken from a VCR
) is fitted into the door frame and works very well.
Good luck
Gerard Zuideveld
>> Has anyone ever seen a detector which can tell the alarm system that the
>> door is locked (e.g. with a deadbolt), not just that it's closed?
I`ve worked for a company that installed security systems. Sometimes we had to
install systems that armed when the main door was on the night-lock. We
therefore installed a microswitch in the lock. This is a simple procedure,
there`s space enough for a small microswitch. The only problem is to make
connect a wire to the door in such a way this coulndn`t cause any problems. We
used a felxible piece of metal pipe, specially suited for this.
In this way people couldn`t forget arming the security system.
CU, Gerard
Brett Kappenman
> Has anyone ever seen a detector which can tell the alarm system that the
> door is locked (e.g. with a deadbolt), not just that it's closed?
>
>
> Stefan Demetrescu (ste...@xenon.stanford.edu)
It seems to me that it would be fairly simple to do. First of all you could
magnetize the deadbolt so that there was a fairly strong magnetic field coming
from it. Then all you would have to do is get a magnetic door sensor and
place it in the deadbolt hole. When the deadbolt is locked, it should be close
enough to trigger the deadbolt switch. That's a great idea. I think I might
install one.
Could you imagine that. The robber breaks the window to unlock the deadbolt.
The minute he unlocks the door, bingo the alarm goes off.
Cool.
George Photakis
kapp...@carver.com (Brett Kappenman) wrote:
>In article <stefand-0508...@dialin33532.slip.nts.uci.edu>,
ste...@xenon.stanford.edu (Stefan Demetrescu) writes:
>> Has anyone ever seen a detector which can tell the alarm system that the
>> door is locked (e.g. with a deadbolt), not just that it's closed?
>It seems to me that it would be fairly simple to do. First of all you could
>magnetize the deadbolt so that there was a fairly strong magnetic field
coming
>from it. Then all you would have to do is get a magnetic door sensor and
>place it in the deadbolt hole. When the deadbolt is locked, it should be
>close enough to trigger the deadbolt switch.
This is along what I was thinking but instead of trying to magnitize the door
bold my thought was just to drill a small hole in the end of the bolt (I know
it's hardened steel but it can be done) and insert a small rare earth magnet.
Then countersink the mag switch in the jam and away you go.
g
Edward Cheung
>bold my thought was just to drill a small hole in the end of the bolt (I know
>it's hardened steel but it can be done) and insert a small rare earth magnet.
If the bolt is indeed steel (or another ferous material) this may not work.
Since the magnetic permeability of steel is very good, most of the
magnetic field lines will pass thru the steel surrounding the
magnet, and very little will will escape into the space at the end of the
bolt. As a consequence, the magnetic sensor (hall, reed, etc.) will not
'see' much of the magnet.
It may be better to deepen the hole that accepts the bolt, and glue the
magnet onto the end of the bolt with both poles exposed (small magnet).
Slide the magnet right upto the switch.
Comments?
+---------------------------------------------------------------------------+
| Edward Cheung, Ph.D. | The opinions expressed herein |
| NASA Goddard Space Flight Center | do not necessarily reflect |
| Code 714.1, Bldg T11B | those of my employers' |
| Greenbelt, MD 20771 | |
| 301-286-1269(office) 286-1717(fax) | My next book: |
| Internet: ebc...@rs710.gsfc.nasa.gov | Statistics, Demos and Other Lies |
+---------------------------------------------------------------------------+
George Photakis
ebc...@rs710.gsfc.nasa.gov (Edward Cheung) wrote:
>>From: geo...@infinet.com (George Photakis)
>
>>bold my thought was just to drill a small hole in the end of the bolt (I
know
>>it's hardened steel but it can be done) and insert a small rare earth
magnet.
>
>If the bolt is indeed steel (or another ferous material) this may not work.
>
>Since the magnetic permeability of steel is very good, most of the
>magnetic field lines will pass thru the steel surrounding the
>magnet, and very little will will escape into the space at the end of the
>bolt. As a consequence, the magnetic sensor (hall, reed, etc.) will not
>'see' much of the magnet.
>
>It may be better to deepen the hole that accepts the bolt, and glue the
>magnet onto the end of the bolt with both poles exposed (small magnet).
>Slide the magnet right upto the switch.
>
That's the main reason why I suggested a rare earth magnet instead of a normal
ferious one. The rare earth one should be strong enough to trip the small
microswitch in the jam sensor.
Simply glueing the magnet on the outside of the bold may be a problem with the
clearance of the door to the jam. On my front door there is less than an 1/8
inch clearance. Gluing anything to the bolt will not allow the door to close.
Deepening the hole wouldn't to much good because the door wouldn't close
enough to allow the bolt to be thrown.
Either way it should be interesting to try it out. Hope anyone who gives it a
shot will post their experiences here.
George
Rob-L
: It may be better to deepen the hole that accepts the bolt, and glue the
: magnet onto the end of the bolt with both poles exposed (small magnet).
: Slide the magnet right upto the switch.
Why not just put a pin-switch in the hole where the bolt goes?
Bolt goes in, pushes switch, switch opens or closes (either type possible).
Put a little pad or something on the end of the pin to adjust and cushion it.
Alternatively, you could place an optical sensor in the hole, which the
bolt triggers by breaking the beam, or by reflecting off the end to
reflect a specific pulse frequency back at a reflection sensor when it is
close enough.
Edward Cheung
> clearance of the door to the jam. On my front door there is less than an 1/8
>inch clearance. Gluing anything to the bolt will not allow the door to close.
Oops, you are right!
Mike Morris
>In article <stefand-0508...@dialin33532.slip.nts.uci.edu>, ste...@xenon.stanford.edu (Stefan Demetrescu) writes:
>> Has anyone ever seen a detector which can tell the alarm system that the
>> door is locked (e.g. with a deadbolt), not just that it's closed?
>>
>>
>> Stefan Demetrescu (ste...@xenon.stanford.edu)
>
>It seems to me that it would be fairly simple to do. First of all you could
>magnetize the deadbolt so that there was a fairly strong magnetic field coming
>from it. Then all you would have to do is get a magnetic door sensor and
>place it in the deadbolt hole. When the deadbolt is locked, it should be close
>install one.
>
>Could you imagine that. The robber breaks the window to unlock the deadbolt.
>The minute he unlocks the door, bingo the alarm goes off.
Or just put a button in the deadbolt hole (normally closed or normally open,
your choice)... When the pressure of the deadbolt is removed, the button opens.
Saves the hassle of magnetizing the deadbolt.
--
Mike Morris play: mor...@grian.cps.altadena.ca.us
Network Technology Development Group work: Michael....@jpl.nasa.gov
Jet Propulsion Laboratory M/S 126-130 818-393-3872 fax 818-393-3875
4800 Oak Grove Dr. Pasadena, CA. 91109
Chuck Rinker
>That's the main reason why I suggested a rare earth magnet instead of a normal
>ferious one. The rare earth one should be strong enough to trip the small
>microswitch in the jam sensor.
>Simply glueing the magnet on the outside of the bold may be a problem with the
> clearance of the door to the jam. On my front door there is less than an 1/8
>inch clearance. Gluing anything to the bolt will not allow the door to close.
> Deepening the hole wouldn't to much good because the door wouldn't close
>enough to allow the bolt to be thrown.
>Either way it should be interesting to try it out. Hope anyone who gives it a
> shot will post their experiences here.
Pardon my ignorance on this subject as I am new to the field of home
automation, but isn't there a simpler solution using a standard
contact sensor. One that could be embedded in the socket that would
be closed as the dead-bolt is locked?
Also...who do you usually recommend for a source for X10 products?
Thanks for your help...
Duqun
I use a pushbutton type switch installed in the deadbolt or lockset hole
in the door frame. The pressure of the bolt pushes the switch in telling
your alarm that the door is indeed locked. All of your magnet ideas WILL
NOT work.
Good Luck
Jimkoke
pressure of the deadbolt - who will provide a source and part number for
such a switch??
I had thought of doing this years ago, but could not find the appropriate
part --
until I walked through an auto-parts store. The switches used for
detecting a
closed car door seemed ideal, but most were not threaded for being screwed
into a door jamb.
Any other thoughts?
Charles Smith
back of the deadbolt hole. You would then drill the end of the deadbolt
and press or glue a small bar magnet in it. You probably would have to
use a narrow gap switch as not to show a false locked condition.
Rob-L
: Now that the consensus is to use a mechanical switch activated by the
: pressure of the deadbolt - who will provide a source and part number for
: such a switch??
Radio Shack "Short pin switch" 49-508 ($2.99/2pk)
or "Long pin switch" 49-509 ($2.99/2pk)
Both are threaded, and they are sold for car alarm systems. They have
one contact with a lug or crimp connector, and I guess you tie your other
wire to the switch body. Don't know if they're normally open or closed
switches.
Brian Edwards
From bedw Tue Sep 26 11:48:31 1995
To: jim...@aol.com (Jimkoke)
Cc:
Subject: Re: Need sensor to detect if door is locked (not just closed)
In article <43ehj8$4...@newsbf02.news.aol.com> you write:
|>Now that the consensus is to use a mechanical switch activated by the
|>pressure of the deadbolt - who will provide a source and part number for
|>such a switch??
|>
|>part --
|>until I walked through an auto-parts store. The switches used for
|>detecting a
|>closed car door seemed ideal, but most were not threaded for being screwed
|>into a door jamb.
|>
|>Any other thoughts?
|>
the planet!
Look out for cupboard door switches; ones that go "click" when you press
them. They'll probably be better.
----------------------------------------------------------------
Brian Edwards "Still running against the wind"
10002...@CompuServe.Com -Bob Seger
be...@btma57.se.bel.alcatel.be
Richard Pritzker
I have experience in electrical devices that can sense that a door lock
(locking device like a deadbolt) is secured.
(The auto switch idea sounds ok... but why not just use a plunger type
switch available from Radio Shack. Car switches are designed for sheet
metal installation, are negative ground based and dificult to adjust.
Probably not the best choice for this application.)
One manufactured product is the Model 103 Strike Actuator Switch by the
Folger Adam Company. The product is basically a strike box with a
microswitch mounted inside for the deadbolt to depress when extended.
However, the device can easily be fooled with a wad of paper and is very
expensive. Folger Adam products are available from a Contract Hardware
distributor or from a prison hardware vendor. Something could be
fabricated to accomplish the task by taking a metal strike box (available
from a locksmith or hardware store) and mounting a microswitch.
Another possibility is drilling a hole and placing a magnet into the locks
deadbolt. Then, place a small reed switch deep in the strike box. (In this
case a plastic box would probably be prefered.)
Still another possibility is to get an electric strike with the sensing
switch already built in. (Try Adams-Rite, Rofu, Folger Adam or maybe even
Trine.)
Hope this helps.