John,

agreed a lot of pipe would be needed.
But also a lot of seismic sensors if they would be used.

I think it depends on what kind of protection Mr King is looking for.
A standard 4.5Hz geophones can detect motion of a human body=20
walking normally at about 5-10 meters but not more and not at all if
he is walking softly.
The cost of a 50 meters of rubber pipe is small if compared to the
cost of a single geophones that cannot pick that range.
You have to consider that spacing geophones at 50 meters
(to be large) you will need anyway 50 meters or more of twisted
cable to lead the signal to a sort of peamplifier or digitizer for=20
analysis.

If I don't remember bad there should also some sort of piezo wires
that could be useful for the same pourposes but obviously
several km of piezo wire would be very expensive.

Regards
Mauro


  ----- Original Message -----=20
  From: John Hernlund=20
  To: psn-l@.................
  Sent: Wednesday, April 09, 2003 9:35 AM
  Subject: Re: Intrusion Sensors


  On Tuesday, April 8, 2003, at 11:56 PM, Mauro Mariotti wrote:

    Hi Mr. King,
    I think that the major problem is what sensor to use instead of
    what amplifier use.
    Geophones have a limited detection range and not detect a person
    that eventually walk softly.
    It could detect a running animal instead or an animal trying to bury
    something near the sensor.
    Probably a better sensor is a pressurized rubber pipe buried along =
the border
    that could be long 10 - 20 meters or more.
    Then you can measure the pressure variation at one extremity when
    someone walk over it.


  That would take a lot of pipe...but maybe a better idea for sensors. I =
talked to an army guy who once did seismic sensors in the first Iraq =
war. They have (of course!) an acronym for this job, though I don't =
remember it...I don't think he even remembered what it stood for. He =
told me they are mostly designed to detect artillery sources, and =
combined with radar methods (he called it fire-finding radar, or =
something like that) pin point the location of an enemy's artillery and =
then be able to fire back at the correct position. He also said that it =
could pick up large vehicle convoys or even people on foot when they =
were very numerous and fairly close.=20

  What works in the Army tends not to be the case along the AZ border, =
which is run by coyotes hauling mostly smaller groups of people on =
foot...some times abandoning large numbers of them in the middle of the =
desert leading to hundreds of deaths from heat exhaustion, etc.. On a =
number of occasions I've run across a taxi looking for fares in the =
middle of the desert! In a few border towns there have been incidents of =
thousands of people lining up along the border, and then crossing all at =
once...thus overwhelming the border patrol...but not much is able to =
stop this from happening. The worst is the drug runners who are almost =
always armed and quite willing to shoot first and see who it is =
later...this may account for the low morale in the border patrol in some =
areas, since quite a few of them have been killed. No doubt about it, =
the lax border enforcement in the past decade in Arizona has caused this =
to be the main conduit for illegal cross-border activity in the US. It =
has brought the Mexican mafia into Phoenix, where they took control of =
much of the illegal activity there. They are a bold and brutal =
organization, and even wear clothing, drive trucks, etc. in a uniform =
way that announces who they are; i.e. their presence and lack of fear. A =
friend of mine, a Phoenix cop, lost his partner when a group of them =
telephoned the police and laid a trap...apparently just for "fun."

  So no doubt about it, this is a serious problem. Dealing with it is =
not trivial, and the complexities involved are mind-boggling. Arizona is =
the sixth largest state in the US, and contains 193 separate (and =
unsettled) mountain ranges that really makes it possible for much to =
happen off the beaten track. But there is always room for innovations. =
Some cities have set up microphones to detect gun shot locations before =
the inevitable 911 call. People need to just keep thinking and being =
creative, and a solution could present itself.

  Cheers!
  John







John,
 
agreed a lot of pipe would be =
needed.
But also a lot of seismic sensors if =
they would be=20
used.
 
I think it depends on what kind of =
protection Mr=20
King is looking for.
A standard 4.5Hz geophones can detect =
motion of a=20
human body 
walking normally at about 5-10 =
meters but not=20
more and not at all if
he is walking softly.
The cost of a 50 meters of rubber pipe =
is small if=20
compared to the
cost of a single geophones that cannot =
pick that=20
range.
You have to consider that spacing =
geophones at 50=20
meters
(to be large) you will need anyway 50 =
meters or=20
more of twisted
cable to lead the signal to a sort of =
peamplifier=20
or digitizer for 
analysis.
 
If I don't remember bad there should =
also some sort=20
of piezo wires
that could be useful for the same =
pourposes but=20
obviously
several km of piezo wire would be very=20
expensive.
 
Regards
Mauro
 
 

  
----- Original Message ----- 
  From:=20
  John=20
  Hernlund 
  
To: psn-l@.............. 
  
Sent: Wednesday, April 09, 2003 =
9:35=20
  AM
  
Subject: Re: Intrusion =
Sensors
  

On Tuesday, April 8, 2003, at 11:56 PM, Mauro Mariotti=20
  wrote:

  
Hi Mr. =
King,
I =

    think that the major problem is what sensor to use instead =
of
what =

    amplifier use.
Geophones=20
    have a limited detection range and not detect a =
person
that=20
    eventually walk =
softly.
It=20
    could detect a running animal instead or an animal trying to =
bury
something=20
    near the sensor.
Probably=20
    a better sensor is a pressurized rubber pipe buried along the =
border
that=20
    could be long 10 - 20 meters or =
more.
Then=20
    you can measure the pressure variation at one extremity =
when
someone=20
    walk over it.

That =
would take a=20
  lot of pipe...but maybe a better idea for sensors. I talked to an army =
guy who=20
  once did seismic sensors in the first Iraq war. They have (of course!) =
an=20
  acronym for this job, though I don't remember it...I don't think he =
even=20
  remembered what it stood for. He told me they are mostly designed to =
detect=20
  artillery sources, and combined with radar methods (he called it =
fire-finding=20
  radar, or something like that) pin point the location of an enemy's =
artillery=20
  and then be able to fire back at the correct position. He also said =
that it=20
  could pick up large vehicle convoys or even people on foot when they =
were very=20
  numerous and fairly close. 

What works in the Army tends not to =
be the=20
  case along the AZ border, which is run by coyotes hauling mostly =
smaller=20
  groups of people on foot...some times abandoning large numbers of them =
in the=20
  middle of the desert leading to hundreds of deaths from heat =
exhaustion, etc..=20
  On a number of occasions I've run across a taxi looking for fares in =
the=20
  middle of the desert! In a few border towns there have been incidents =
of=20
  thousands of people lining up along the border, and then crossing all =
at=20
  once...thus overwhelming the border patrol...but not much is able to =
stop this=20
  from happening. The worst is the drug runners who are almost always =
armed and=20
  quite willing to shoot first and see who it is later...this may =
account for=20
  the low morale in the border patrol in some areas, since quite a few =
of them=20
  have been killed. No doubt about it, the lax border enforcement in the =
past=20
  decade in Arizona has caused this to be the main conduit for illegal=20
  cross-border activity in the US. It has brought the Mexican mafia into =

  Phoenix, where they took control of much of the illegal activity =
there. They=20
  are a bold and brutal organization, and even wear clothing, drive =
trucks, etc.=20
  in a uniform way that announces who they are; i.e. their presence and =
lack of=20
  fear. A friend of mine, a Phoenix cop, lost his partner when a group =
of them=20
  telephoned the police and laid a trap...apparently just for =
"fun."

So=20
  no doubt about it, this is a serious problem. Dealing with it is not =
trivial,=20
  and the complexities involved are mind-boggling. Arizona is the sixth =
largest=20
  state in the US, and contains 193 separate (and unsettled) mountain =
ranges=20
  that really makes it possible for much to happen off the beaten track. =
But=20
  there is always room for innovations. Some cities have set up =
microphones to=20
  detect gun shot locations before the inevitable 911 call. People need =
to just=20
  keep thinking and being creative, and a solution could present=20
  itself.

Cheers!
John