metal dector for barbed wire fences

[Hul Tytus]

comp.arch.embedded,sci.electronics.components
metal dector for barbed wire fences

Anybody here have any suggestions for possible ways to detect fence wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?
Typical mounting would be on a tractor or trailer, so the detector would need
a sense of direction, ie looking outward not inward. Minimum range would be
around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal free
environment, leaving the methods they use somewhat doubtful. Evidently, there
are detectors with seperate heads/coils and 1-5 foot ranges but, once again,
require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the other
recieving a reflection from the wire(s). A parabolic or corner reflector type
antenna maybe if not for the high frequency - two 12 inch antenna's would be
about max size and that's in the gigaherts range, which might be a problem.
Any suggestions along this line will be appreciated.

Hul

 

[Tim Wescott]

On Sat, 16 Jun 2012 15:04:18 +0000, Hul Tytus wrote:

comp.arch.embedded,sci.electronics.components metal dector for barbed
wire fences

Anybody here have any suggestions for possible ways to detect fence
wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square
matrix? Typical mounting would be on a tractor or trailer, so the
detector would need a sense of direction, ie looking outward not inward.
Minimum range would be around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal
free
environment, leaving the methods they use somewhat doubtful. Evidently,
there are detectors with seperate heads/coils and 1-5 foot ranges but,
once again, require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the
other
recieving a reflection from the wire(s). A parabolic or corner reflector
type antenna maybe if not for the high frequency - two 12 inch antenna's
would be about max size and that's in the gigaherts range, which might
be a problem.
Any suggestions along this line will be appreciated.

Hul

What are you actually trying to do? Is this an operator aid, to keep
from driving into the fence, or for a robotic tractor, or what?

You may be able to make a metal detector directional simply by backing up
the detection coil with a metal plate, one or two feet back. Metal
detectors work with near-field radiation of a low frequency signal (in
the 100's of kHz, if I recall correctly), and look for changes in the
coil inductance caused by nearby metal. Placing the coil a foot or two
from the metal backing will leave the detector "detecting" the backing --
but it'll be constant; as long as there's enough change from the metal
you want to detect, things should work.

 

[Paul]

In article <jri79h$opj$1@reader1.panix.com>, ht@panix.com says...

comp.arch.embedded,sci.electronics.components
metal dector for barbed wire fences

Anybody here have any suggestions for possible ways to detect fence wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?
Typical mounting would be on a tractor or trailer, so the detector would need
a sense of direction, ie looking outward not inward. Minimum range would be
around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal free
environment, leaving the methods they use somewhat doubtful. Evidently, there
are detectors with seperate heads/coils and 1-5 foot ranges but, once again,
require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the other
recieving a reflection from the wire(s). A parabolic or corner reflector type
antenna maybe if not for the high frequency - two 12 inch antenna's would be
about max size and that's in the gigaherts range, which might be a problem.
Any suggestions along this line will be appreciated.

Hul

Alternatively use the barb wire fence as an antenna for LF low power
signal and get the strength detection of carrier to denote when too
close.



--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font
<http://www.gnuh8.org.uk/> GNU H8 - compiler & Renesas H8/H8S/H8 Tiny
<http://www.badweb.org.uk/> For those web sites you hate

 

[Jamie]

Hul Tytus wrote:

comp.arch.embedded,sci.electronics.components
metal dector for barbed wire fences

Anybody here have any suggestions for possible ways to detect fence wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?
Typical mounting would be on a tractor or trailer, so the detector would need
a sense of direction, ie looking outward not inward. Minimum range would be
around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal free
environment, leaving the methods they use somewhat doubtful. Evidently, there
are detectors with seperate heads/coils and 1-5 foot ranges but, once again,
require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the other
recieving a reflection from the wire(s). A parabolic or corner reflector type
antenna maybe if not for the high frequency - two 12 inch antenna's would be
about max size and that's in the gigaherts range, which might be a problem.
Any suggestions along this line will be appreciated.

Hul

Ultra sonic projected on the fence wire should make it vibrated. A
ultrasonic mic just behind the transducer should detect this.

Fence wire is a hard surface and the only thing I can see that may
hamper this is rust..

If you transmit a low frequency magnetic wave in the vicinity,
surface rust on the metal may produce some nice G/T hz signals. Of
course, you need a detector for that. Maybe IR . who knows..

Jamie

 

Paul - that's definite possibility but, as you say, an alternative if
"plan a" doesn't prove feasible.

Hul

In comp.arch.embedded Paul <paul@pcserviceselectronics.co.uk> wrote:

In article <jri79h$opj$1@reader1.panix.com>, ht@panix.com says...

comp.arch.embedded,sci.electronics.components
metal dector for barbed wire fences

Anybody here have any suggestions for possible ways to detect fence wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?
Typical mounting would be on a tractor or trailer, so the detector would need
a sense of direction, ie looking outward not inward. Minimum range would be
around one foot with 4 feet probably optimum.
Typical retail metal detectors have a short range and need a metal free
environment, leaving the methods they use somewhat doubtful. Evidently, there
are detectors with seperate heads/coils and 1-5 foot ranges but, once again,
require a metal free environment.
One possible area would utilize rf antenna's, one transmiting and the other
recieving a reflection from the wire(s). A parabolic or corner reflector type
antenna maybe if not for the high frequency - two 12 inch antenna's would be
about max size and that's in the gigaherts range, which might be a problem.
Any suggestions along this line will be appreciated.

Hul

Alternatively use the barb wire fence as an antenna for LF low power
signal and get the strength detection of carrier to denote when too
close.

--
Paul Carpenter | paul@pcserviceselectronics.co.uk
http://www.pcserviceselectronics.co.uk/> PC Services
http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font
http://www.gnuh8.org.uk/> GNU H8 - compiler & Renesas H8/H8S/H8 Tiny
http://www.badweb.org.uk/> For those web sites you hate

 

[Morten Leikvoll]

"Hul Tytus" skrev i nyhetsmeldingen: jri79h$opj$1@reader1.panix.com ...

Anybody here have any suggestions for possible ways to detect fence
wire,
mostly 1, 2 or 3 levels of barbed wire but also some 8 inch square matrix?

This application makes my head shouts "radar!".. not metal detector..