Looking for some advice on the most appropriate sensors for a moored
cruiser. I have switches on the door, the hatch and some windows, I have
two infra red motion detectors and a pressure mat.

Are the IR detectors any good on a boat that sways a lot in the wind etc?
Any other options?

Thanks in advance

IR sensors will detect the heat generated by someone in your boat. It's
ultrasound sensors that would be trigered by the motion of something moving
in your boat. But what if the boat's interior is heated to higher than the
body's temperature on a sunny day? I dunno enough about this to risk a
categoric answer. But I GUESS it would generate a false alarm.

Jean Dufour
Montreal, Qc

John Smith wrote:

Looking for some advice on the most appropriate sensors for a moored
cruiser. I have switches on the door, the hatch and some windows, I have
two infra red motion detectors and a pressure mat.

Are the IR detectors any good on a boat that sways a lot in the wind etc?
Any other options?

Thanks in advance

I think IR sensors set off an alarm when the "picture" of IR changes. I have
done some testing with home security alarams, and if you really move slowly,
the alarm will not go off.

Haakon

"Jean Dufour" wrote in message
...
IR sensors will detect the heat generated by someone in your boat. It's
ultrasound sensors that would be trigered by the motion of something
moving
in your boat. But what if the boat's interior is heated to higher than the
body's temperature on a sunny day? I dunno enough about this to risk a
categoric answer. But I GUESS it would generate a false alarm.

Jean Dufour
Montreal, Qc

John Smith wrote:

Looking for some advice on the most appropriate sensors for a moored
cruiser. I have switches on the door, the hatch and some windows, I
have
two infra red motion detectors and a pressure mat.

Are the IR detectors any good on a boat that sways a lot in the wind
etc?
Any other options?

Thanks in advance

After trying various moored boat setups with false alarms, I found that an
ultrasonic motion detector wired in series with an IR motion detctor works
PERFECT. No false alrams ever, and will alarm if a person intrudes. The
ultrasonic units are considered obsolete, but you can still find them on eBay.

"Jean Dufour" wrote in message
...
IR sensors will detect the heat generated by someone in your boat. It's
ultrasound sensors that would be trigered by the motion of something
moving
in your boat. But what if the boat's interior is heated to higher than the
body's temperature on a sunny day? I dunno enough about this to risk a
categoric answer. But I GUESS it would generate a false alarm.

They don't. IR sensors 'look' into the area in sectors, like A-B-A-B-A-B and
reacts on the difference between A and B. If the environment temperature
changes, both the A and B sectors change, hence no alarm. If someone walks
through the area, A changes, then B, then A again. The alarm trigger is set
to the amount of change and the number of changes. It can be set so
accurately that it wouldn't alarm on a cat or a small dog, but only on a
large enough body, like a human. Because is reacts on changes, it also does
not alarm on a sudden sunshine through a porthole.

Meindert

Anyone found a source for 12 volt IR detectors?


"John Smith" wrote in message
...
Looking for some advice on the most appropriate sensors for a moored
cruiser. I have switches on the door, the hatch and some windows, I have
two infra red motion detectors and a pressure mat.

Are the IR detectors any good on a boat that sways a lot in the wind etc?
Any other options?

Thanks in advance

On Thu, 11 Dec 2003 19:29:21 GMT, "padeen"
wrote:

Anyone found a source for 12 volt IR detectors?

I hope You are joking, as they are all 12V for normal alarm use.
/Marcus

--
Marcus AAkesson
Gothenburg Callsigns: SM6XFN & SB4779
Sweden
Keep the world clean - no HTML in news or mail !

Marcus, are you capable of understanding that your post reveals our combined
ignorance? I'm an electrician who's been installing 120V IR sensors for
many years, but haven't had any alarm experience. You, on the other hand,
see the world from the 12V side. Shall we both broaden our knowledge?

Padeen


"Marcus AAkesson" wrote in message
...
On Thu, 11 Dec 2003 19:29:21 GMT, "padeen"
wrote:

Anyone found a source for 12 volt IR detectors?

I hope You are joking, as they are all 12V for normal alarm use.
/Marcus

--
Marcus AAkesson
Gothenburg Callsigns: SM6XFN & SB4779
Sweden
Keep the world clean - no HTML in news or mail !

"padeen" wrote in message
...
Marcus, are you capable of understanding that your post reveals our
combined
ignorance? I'm an electrician who's been installing 120V IR sensors for
many years, but haven't had any alarm experience. You, on the other hand,
see the world from the 12V side. Shall we both broaden our knowledge?


Well, I think Marcus is right. I think it would be fair to say that ALL IR
sensors for alarm applications are 12V, since it doesn't make sense to run
an alarm sensor at 120V when it will be connected to an alarm system that
works on low voltage. I think the 120V or 240V types you refer to are the
ones used to control a light. And you don't want to use these for an alarm
system because they react on anything. The alarm types are better in
discriminating between events that are important (moving people) and not
important (moving small animals for instance).

Meindert

The 120V sensors will control anything you want them to control, and have
considerable adjustment capabilities so as not to "react on anything",
including small animals, wind-propelled trees, or street traffic. But of
course all 12V alarm systems would have 12V sensors! However, I would
expect that the internal sensor electronics for both 12 and 120V is
essentially similar, with the difference being only in the PS & switch.

Padeen



"Meindert Sprang" wrote in message
...
"padeen" wrote in message
...
Marcus, are you capable of understanding that your post reveals our
combined
ignorance? I'm an electrician who's been installing 120V IR sensors for
many years, but haven't had any alarm experience. You, on the other
hand,
see the world from the 12V side. Shall we both broaden our knowledge?


Well, I think Marcus is right. I think it would be fair to say that ALL IR
sensors for alarm applications are 12V, since it doesn't make sense to run
an alarm sensor at 120V when it will be connected to an alarm system that
works on low voltage. I think the 120V or 240V types you refer to are the
ones used to control a light. And you don't want to use these for an alarm
system because they react on anything. The alarm types are better in
discriminating between events that are important (moving people) and not
important (moving small animals for instance).

Meindert