Door annunciator...

I'm looking for a door annunciator...a simple, wired, line-powered one. Goes BONG when the door opens.

Not battery-powered {they go dead}. Not wireless {why?} as the alarm will be at the door. Not straight mechanical {"EZTone"} as I need an on/off switch.

You'd think someone sold such, but I've Googled/Froogled/etc until my fingers are blue.

Yea, I could build such with a one-shot, etc...but the economics of scale..

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A host is a host from coast to coast.................wb8foz@nrk.com
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Reply to
David Lesher
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One of the first hits I got was this one:

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Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Hello David,

Maybe just a normal doorbell with a mometary door contact that closes briefly while the door swings by?

Ours are powered by food and water. They don't emit a "Bong" but a "Woof". They also have another signaling mode when a delivery van pulls up: "Woof...rrrrr...grrrr...WOOOOFFFFF!". The third mode is for fire engines: "Wahooooooooooooo", which one of them can hold for 7-8 seconds.

Regards, Joerg

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Reply to
Joerg

There was in fact a clever switch that did just that. It was a pendulum that hung 1" inside the door, with a contact on one side so as the door opened, but not closed, it closed. I have not seen one in 30+ years.

Did I mention this is an office? The FedEx and UPS folks are our FRIENDS...

And as for

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the only one I see there that's close is the air pressure one. Err, no thanks. This is an interior door, from the elevator lobby...

I want a simple mechanical or magnetic sensor on the door; not photobeams, air pressure, or backscatter radar....

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

How about adding a 9 volt battery eliminator (wall wart) to this Radio Shack "Door Alarm and Entry Chime??

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David Lesher wrote:

Reply to
Chuck Wozniak

That may well be my best bet; despite it being 10X as complex as we need. It has 2 NO reed switches within. I can parallel an ordinary alarm contact with those for remote mounting. (The door is in fact a double-door; so I can't mount this as intended....)

Thanks for the lead.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

You could try to find one of the heavy duty pressure mats used for older alarm systems.

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Reply to
Michael A. Terrell

Hello David,

There still is a type of switch that sits above the door and has an oval spring. This spring closes a switch above it while the door is between just a crack and 10 degrees maybe. Many stores have that but the downside is that is also alerts when closing the door.

This is also an office. The dogs alert the same way when anyone pulls up and sometimes that's a good thing. It keeps not so well meaning folks away. When the meter reader comes they make a racket, too, but then sit there next to the meter drooling because he always has dog biscuits. Dogs have an amazing sense of good and bad. When they sense trouble they show some teeth with the growl.

I have heard a Dog bark type electronic alert before. It was pathetic. The bark stopped in the middle of a woof. Intruders aren't that stupid.

Should be no problem. Some electronic "bong" chimes from the hardware stores react to a door bell button the same way whether it is momentarily pressed or held down long. So if you'd get one of these and an "open when released" switch you should be in business. Hardware stores often also have those switches as kits, with brackets, screws and all. They used to be popular to illuminate a walk-in closet or pantry the instant its door was opened. If they don't have them you could look at garage door opener end switches since it's a low voltage application.

Regards, Joerg

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Reply to
Joerg

Mounting arm v ------ || * < microswitch || || || || || ^ DoorFrame

Use an L bracket as a mounting arm for the microswitch. As the door swings by, it makes the switch and the bell (standard doorbell) gord bong.

Ed

Reply to
ehsjr

...

That will signal twice; once as the door opens, the second as it closes... That's what the pendulum type avoided.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

I want to sense the door opening. Not people in the hall walking by same.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

I have seen them just inside the door so you have to step on them to enter.

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Reply to
Michael A. Terrell

Here's a down and dirty trick. Use a spdt contact for the door switch, a big capacitor, 12-24 VDC, common door chime. Feed the +DC to the doorswitch contact that is normally closed when the door is closed. Connect the capacitor (+) to the common terminal of the switch. Connect the door chime to the switch contact that is open when the door is closed. Connect the capacitor ( - ), the -DC and other side of the chime together.

With the door closed, the capacitor charges, When the door is open, the capacitor charge is switched to the door chime and it rings one time. When the door is closed again, the process starts over.

Note: Put an on/off switch where convenient and break one side of the the dc power or a chime lead. Change the value of the capacitor for more or less chime striking force. Use a recessed, surface mount or motion switch as desired.

Hope this helps!

Reply to
lenp

People walk by on the INSIDE of the door.....

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

....

I've considered building same; but prefer not to invest the time. IMHE, it's the mounting+box+etc that eat the time....

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
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Reply to
David Lesher

Here's the pendulum type. Bend the microswitch leaf into a U and hang the chain on it. The weight of the sinker provides enough tension on the chain so that the door opening will cause the leaf to move. You don't need much. Note that the microswitch body is mounted at an angle so that the leaf is perpendicular. The mounting arm for the switch isn't shown. I'm not a fisherman - but a fishing leader might work in place of the chain.

--------o / O / | / / | / /===|

Reply to
ehsjr

That presents a different kind of problem. It should be laid out so that the door can't hit someone walking by, as most entry doors open in, or swing both ways. There are optical sensors that detect the direction of movement, as well as video motion detectors. They use a cheap CCTV camera and you can set two or more crosspoints for detection. The ones I've used had separate dry contact outputs so you add some simple logic to detect direction. There was a simple circuit to build the detector in one of the design magazines around 1990, written by someone at 3M.

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Reply to
Michael A. Terrell

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