smoke detector
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Posts: 46,084
Help.
I want to interface a stamp with an inexpensive smoke detector so that, if
smoke is detected in my workshop, it will activate a relay that will in turn
signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to "alarm"
several other conditions in the workshop.]
My real question is what is the best way to detect the activation of the
smoke detector? My first thought was to open up the smoke detector and tap
directly into it by finding a voltage source that goes "high" when smoke is
detected. But maybe it would make more sense to leave the smoke detector
untouched and "detect" the alarm condition by the sound of the alarm going
off in the workshop. This could then be converted by a (I hope) simple
circuit into an on/off signal suitable for stamp processing. Any ideas
would be appreciated.
HKaresh
I want to interface a stamp with an inexpensive smoke detector so that, if
smoke is detected in my workshop, it will activate a relay that will in turn
signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to "alarm"
several other conditions in the workshop.]
My real question is what is the best way to detect the activation of the
smoke detector? My first thought was to open up the smoke detector and tap
directly into it by finding a voltage source that goes "high" when smoke is
detected. But maybe it would make more sense to leave the smoke detector
untouched and "detect" the alarm condition by the sound of the alarm going
off in the workshop. This could then be converted by a (I hope) simple
circuit into an on/off signal suitable for stamp processing. Any ideas
would be appreciated.
HKaresh
Comments
1) Take a 10uF to 47uF 15V capacitor and wire it directly across the two
battery clips or contact wires of the smoke detector.
2) Take any of the many 6 pin dip opto isolators and connect the opto input
so it is in series with one of the battery wires going to the detector.
The capacitor is required to fool the smoke detector battery sensing
circuit.
(The smoke detector IC performs a simulated battery load test every 15 min.
by drawing current for a millisecond or so and testing the battery voltage
at the end of this period.)
3) connect the opto output via a pull-up to the stamp input
When the buzzer sounds the current goes to 20-40ma and the stamp
input will go low.
Karl
Original Message
From: "H Karesh" <hkaresh@w...>
To: <basicstamps@egroups.com>
Sent: Wednesday, March 22, 2000 2:48 PM
Subject: [noparse][[/noparse]basicstamps] smoke detector
> Help.
> I want to interface a stamp with an inexpensive smoke detector so that, if
> smoke is detected in my workshop, it will activate a relay that will in
turn
> signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to
"alarm"
> several other conditions in the workshop.]
>
> My real question is what is the best way to detect the activation of the
> smoke detector? My first thought was to open up the smoke detector and
tap
> directly into it by finding a voltage source that goes "high" when smoke
is
> detected. But maybe it would make more sense to leave the smoke detector
> untouched and "detect" the alarm condition by the sound of the alarm going
> off in the workshop. This could then be converted by a (I hope) simple
> circuit into an on/off signal suitable for stamp processing. Any ideas
> would be appreciated.
>
>
> HKaresh
>
>
>
> -- Easily schedule meetings and events using the group calendar!
> -- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
independent and no need to worry about impairing it's function. Also if you
need to replace the detector you don't have another project to interface
again.
At 07:48 PM 3/22/00 +0000, you wrote:
>Help.
>I want to interface a stamp with an inexpensive smoke detector so that, if
>smoke is detected in my workshop, it will activate a relay that will in turn
>signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to "alarm"
>several other conditions in the workshop.]
>
>My real question is what is the best way to detect the activation of the
>smoke detector? My first thought was to open up the smoke detector and tap
>directly into it by finding a voltage source that goes "high" when smoke is
>detected. But maybe it would make more sense to leave the smoke detector
>untouched and "detect" the alarm condition by the sound of the alarm going
>off in the workshop. This could then be converted by a (I hope) simple
>circuit into an on/off signal suitable for stamp processing. Any ideas
>would be appreciated.
>
>
> HKaresh
>
>
>
>-- Easily schedule meetings and events using the group calendar!
>-- http://www.egroups.com/cal?listname=basicstamps&m=1
>
>
>
Larry G. Nelson Sr.
mailto:L.Nelson@i...
http://www.ultranet.com/~nr
but (from a data sheet I have) it looks like it works like a relay, i. e. if
the the control current (from the smoke detector circuit) is great enough,
it will activate the working current that will feed (through a resistor) to
input a low voltage into the stamp.
Just to make sure I understand:
the capacitor across the battery clip - Will this defeat the battery
checking circuit of the detector (so I need to manually check the battery
condition occasionally)?
input to the stamp - I need to initially set stamp input pin high, right?
At 07:14 PM 3/22/00 -0500, you wrote:
>Here is my solution:
>1) Take a 10uF to 47uF 15V capacitor and wire it directly across the two
>battery clips or contact wires of the smoke detector.
>2) Take any of the many 6 pin dip opto isolators and connect the opto input
>so it is in series with one of the battery wires going to the detector.
>The capacitor is required to fool the smoke detector battery sensing
>circuit.
>(The smoke detector IC performs a simulated battery load test every 15 min.
>by drawing current for a millisecond or so and testing the battery voltage
>at the end of this period.)
>3) connect the opto output via a pull-up to the stamp input
> When the buzzer sounds the current goes to 20-40ma and the stamp
>input will go low.
>Karl
>
>
>
Original Message
>From: "H Karesh" <hkaresh@w...>
>To: <basicstamps@egroups.com>
>Sent: Wednesday, March 22, 2000 2:48 PM
>Subject: [noparse][[/noparse]basicstamps] smoke detector
>
>
>> Help.
>> I want to interface a stamp with an inexpensive smoke detector so that, if
>> smoke is detected in my workshop, it will activate a relay that will in
>turn
>> signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to
>"alarm"
>> several other conditions in the workshop.]
>>
>> My real question is what is the best way to detect the activation of the
>> smoke detector? My first thought was to open up the smoke detector and
>tap
>> directly into it by finding a voltage source that goes "high" when smoke
>is
>> detected. But maybe it would make more sense to leave the smoke detector
>> untouched and "detect" the alarm condition by the sound of the alarm going
>> off in the workshop. This could then be converted by a (I hope) simple
>> circuit into an on/off signal suitable for stamp processing. Any ideas
>> would be appreciated.
>>
>>
>> HKaresh
>>
>>
>>
>> -- Easily schedule meetings and events using the group calendar!
>> -- http://www.egroups.com/cal?listname=basicstamps&m=1
>>
>>
>
>
>
>
>eGroups.com home: http://www.egroups.com/group/basicstamps
>http://www.egroups.com - Simplifying group communications
>
>
>
>
>
Original Message
From: "H Karesh" <hkaresh@w...>
To: <basicstamps@egroups.com>
Sent: Friday, March 24, 2000 10:04 AM
Subject: [noparse][[/noparse]basicstamps] Re: smoke detector
Close enough,
The current through the input LED will turn on the LED and the light emitted
will make the output transistor conduct (like closing a switch)
This in turn will pull your stamp pin from its high condition to low.
There is no physical circuit connection between the input and output of an
Opto-Isolator. I am not too familiar with stamps as I work with 80C31 cpus
most of the time, but I was under the impression that the stamp inputs are
pulled high after a power reset. I might be wrong on this. If they are
pulled igh by the stamp, you wont need the external pullup resistor.
Karl
> Karl - Thank you for your response. I have not used an opto isolator
before
> but (from a data sheet I have) it looks like it works like a relay, i. e.
if
> the the control current (from the smoke detector circuit) is great enough,
> it will activate the working current that will feed (through a resistor)
to
> input a low voltage into the stamp.
> Just to make sure I understand:
>
> the capacitor across the battery clip - Will this defeat the battery
> checking circuit of the detector (so I need to manually check the battery
> condition occasionally)?
>
> input to the stamp - I need to initially set stamp input pin high, right?
>
>
>
> At 07:14 PM 3/22/00 -0500, you wrote:
> >Here is my solution:
> >1) Take a 10uF to 47uF 15V capacitor and wire it directly across the two
> >battery clips or contact wires of the smoke detector.
> >2) Take any of the many 6 pin dip opto isolators and connect the opto
input
> >so it is in series with one of the battery wires going to the detector.
> >The capacitor is required to fool the smoke detector battery sensing
> >circuit.
> >(The smoke detector IC performs a simulated battery load test every 15
min.
> >by drawing current for a millisecond or so and testing the battery
voltage
> >at the end of this period.)
> >3) connect the opto output via a pull-up to the stamp input
> > When the buzzer sounds the current goes to 20-40ma and the stamp
> >input will go low.
> >Karl
> >
> >
> >
Original Message
> >From: "H Karesh" <hkaresh@w...>
> >To: <basicstamps@egroups.com>
> >Sent: Wednesday, March 22, 2000 2:48 PM
> >Subject: [noparse][[/noparse]basicstamps] smoke detector
> >
> >
> >> Help.
> >> I want to interface a stamp with an inexpensive smoke detector so that,
if
> >> smoke is detected in my workshop, it will activate a relay that will in
> >turn
> >> signal an alarm in the house. [noparse][[/noparse]Note: the stamp is also being used to
> >"alarm"
> >> several other conditions in the workshop.]
> >>
> >> My real question is what is the best way to detect the activation of
the
> >> smoke detector? My first thought was to open up the smoke detector and
> >tap
> >> directly into it by finding a voltage source that goes "high" when
smoke
> >is
> >> detected. But maybe it would make more sense to leave the smoke
detector
> >> untouched and "detect" the alarm condition by the sound of the alarm
going
> >> off in the workshop. This could then be converted by a (I hope) simple
> >> circuit into an on/off signal suitable for stamp processing. Any ideas
> >> would be appreciated.
> >>
> >>
> >> HKaresh
> >>
> >>
>
>>
> >> -- Easily schedule meetings and events using the group calendar!
> >> -- http://www.egroups.com/cal?listname=basicstamps&m=1
> >>
> >>
> >
> >
> >
> >
> >eGroups.com home: http://www.egroups.com/group/basicstamps
> >http://www.egroups.com - Simplifying group communications
> >
> >
> >
> >
> >
>
>
>
>
> eGroups.com home: http://www.egroups.com/group/basicstamps
> http://www.egroups.com - Simplifying group communications
>
>
>
>