On Mon, 12 Feb 2007 21:33:39 -0800, krackula <<krack...@i.am>> wrote:
say you been wanting one of those kewl infrasonic sensor / microphone
units for monitoring those government missile launches, EMP firings
sonic booms or nuke tests ........ just to mention a few.
you been wanting one but the $800 for the differential transducer (
alone, not to mention all the rest ) a " slight " hinderance ??
well here is a way to get a " fantastically " sensitive infrasonic
microphone going for UNDER $100 and if you aren't all that handy
with a soldering iron .... for under $200 ready to go.
under $100 ........
go to this dealer's ebay auctions and buy one of these mamac
pressure sensors ....
http://cgi.ebay.com/MAMAC-TREND-PR-272-6-1-A-1-2-E-Low-Pressure-Trans...
these sensors are far too insensitive BUT the box contains ALL the LP
filter, power supply , and amplifier electronics you need . ready to
go.
remove the sensor in this box and in it's place substitute this
standard 4 wire ( bridge type ) Honeywell DUXL01D
( available from Digikey for $53.00 plus shipping )
http://sensing.honeywell.com/index.cfm?ci_id=140301&la_id=1&pr_id=81288
http://www.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch
add the adjustable syringe w/ leak , parts available here ......
http://www.smallparts.com/products/descriptions/stc-stcy.cfm#reducer
( trimmed capillary tube from old car dash gauges works just fine for
the leak ) ....... I use standard 50cc plastic syringes set to
between 10 and 30 cc depending upon the reference volume freq response
I want )
and " presto " you have the exact equivalent of a $1500 infrasonics
sensor / microphone almost for pocket change.
to complete this setup into a working infrasonics monitoring station.
add the wall wart to the above sensor setup ........ jack the output
of the sensor / microphone into a $25 Dataq a/d kit
http://www.dataq.com/products/startkit/di194rs.htm.......
and that's the whole ball of wax ...... as good ( or even better
really because the government stuff is pretty old ) as the
government's monitoring equipment and a whole lot less expensive.
under $200 ...............
see " project status on .......
http://www.knmi.nl/~evers/infrasound/web-article/how.html
place the sensor under your house or out in the barn etc.
and you have your very own REAL infrasonic monitoring system.
frequency response adjustable from .05 hz to 10 hz ( government
monitoring range ) or .003hz - .03 hz ( for civilian
natural emissions ) ....
pc chart recording resolution and time limited only by the size of
your hard drive and settings in the dataq software that comes in the
kit.
or ......... for $200 you can buy a ready made setup...... ready to
go ..........
see .......... ( the home infrasonics bibles ) .......
the belljar texts .........
http://www.belljar.net/microbar.htm
and the more affordable and desirable alternative.....
http://www.infiltec.com/Infrasound@home/
I have built several of the above setups and from field testing by
several knowledgable groups ....... these puppies work GREAT !!!
FAR better than trying to equalize and modify ( unsuitable )
back-electret microphone carts ..... and WAY better than those
$600 Baratron differential sensors .
these perform VERY well portable ( like with ALL infrasonic
mikes you have to find ways to manage the wind noise / interference
tho it's pretty easily taken care of ) and wonderful in a home
setup with the plastic pipe wind screens
( seen on the bottom of the page on this site )
http://www.knmi.nl/~evers/infrasound/web-article/how.html
sonic booms and mine blasting are EASILY recorded at distances of
several hundred miles and up with this setup. ( plastic pipe wind
screen used portable )
you would be very surprised at the number of infrasonic " events "
that can happen all around you and one would never know without the
proper equipment to detect it. the government is responsible for a
large number of these events in western Nevada , along with some
mining operations ( but there are others WELL worth checking out as
well ) .
think true infrasonics are beyond your ability ( especially
financially ) to own them ...... look this material over and think
again .
you can do it easily yourself and get fantastic results ......
if you run into baseline and / or offset level issues with the above
combination of equipment ( primarily with the single ended dataq
digitizer ) then an affordable and more desirable alternative is the
bipolar input Dataq USB cable a / d digitizer ... being sold on ebay
( as are all dataq products ) for a reduced price of only $50. see
in this auctionhttp://cgi.ebay.com/DATAQ-DI-148U-Data-Acquisition-Unit_W0QQitemZ3000...
for only $50. this adds slightly ( $25 ) to the cost of the under $100
setup mentioned above but is well worth the added cost.
I generally run a four channel setup with the infrasonics detector in
one channel, a vertical and horizontal seismic sensor on two more,
and an environmental fluxgate magnetometer in the 4th channel
( on one inexpensive older laptop ) .
like with the above equipment suggestions , the additional equipment
needed for this total setup is inexpensive and easy to assemble.
used seismic geophones are commonly available on ebay for under $10 ea
http://cgi.ebay.com/3-Seismic-vertical-geophone-28-HZ-for-earthquakes...
and simple economical preamp info is available here ....
http://www.infiltec.com/seismo/http://www.infiltec.com/seismo/inf-qm45.htm
or buy older inexpensive used analog Keithley microvolt meters on
ebay and use those for preamps ....... ( they run on internal
batteries for nifty portable use as well )
and used fluxgate magnetometers are frequently seen on ebay or buy
and build the very affordable Fat Quarter's magnetometer kit ( it's
, of course , long period only )
http://www.fatquarterssoftware.com/product.aspx?id=18
http://72.14.253.104/search?q=cache:XLk3zviKLOMJ:www.directivesystems...http://home.planet.nl/~pa1six/sam/manual.htmlhttp://apwww.stmarys.ca/~lonc/magnet.html
very little or possibly ( as some people claim ) absolutely nothing
can slip past a set of instruments as mentioned above. similar
combinations are commonly used in government circles ( generally
with even more channels and more detailed sensors ) and works
" extremely " well in the field , portable. the ability to
discriminate between natural phenomena and " unnatural phenomena "
is the key element of this setup ( besides being able to detect
nearly " everything " interesting you want to find happening in your
Nevada or eastern California desert environment ) .
just about anyone , with a small amount of technical exposure, can
assemble the equipment mentioned above. it's fairly easy to do and the
" results ' of using this setup are impressive to say the least.
the only downside to all of this is the usual problem ( like with any
of this hobby ) is being there when the " phenomena " is happening
or at least recording the sensor results 24 / 7 and reviewing the
results as an alternative. this equipment makes the latter do-able,
if you can't be in the area full time.
the addition of additional channels of SID ( sudden atmospheric
disturbance ) sensors / receivers ....
http://www.infiltec.com/SID-GRB@home/http://www.aavso.org/observing/programs/solar/easySID.shtml
and Schumann waves ( capable ) equipment is HIGHLY recommended
for the advanced user of the equipment mentioned .....http://www.vlf.it/matteobruna/ULF_Induction-Coil.htmhttp://www.vlf.it/re_2/schumannsearch.htmlhttp://www.vlf.it/
wavebender magnetics shows many affordable schumann wave capable
equipment suggestions , type " wavebender magnetics " into Google
for more info on his equipment.
( some people , scientists and engineers, think that the schumann
receivers are the do all - be all of all the environmental monitoring
equipment and will reveal more natural and un-natural phenomena than
all the rest of the equipment combined.
they point to spectra like these as exampleshttp://xoomer.alice.it/rromero/ULFgallery3/ULFgallery3.htmlhttp://xoomer.alice.it/rromero/ULFgallery2/ULFgallery2.htmhttp://xoomer.alice.it/rromero/ULFgallery1/unexplained.htm
myself, I have found that if you live in populated areas, the
schumann wave equipment is trashed by man made interference that
cannot be overcome without moving to unpopulated areas , unfortunately
)
the US Government has contractors located in Colorado, Utah,
Alaska , and Wyoming ( to mention a few , stateside and others
worldwide ) that have " serious " sensor / monitoring equipment
as mentioned above ( especially the fluxgate, schumann, and infrasonic
) which is manned 24 / 7 to monitor and record information. they say
it's used to detect nuclear testing and missile launches world wide
and for some defense purposes ........ but who knows what the full
range of applications actually are ? the wide open possibilities
are very interesting tho ..........
got your infrasound system up and running ....... here is a handy site
to check your results with theirs for comparison and waveform
recognition and analysis ..... a very handy resources to use to
learn about what you are seeing with your system. http://www.gi.alaska.edu/infrasound/Infrasound257.htmhttp://www.sethwhite.org/science%20tech%20links.htm