Subject: Folded pendulum history From: "David H. Youden" dyouden@......... Date: Mon, 31 Mar 2003 17:20:58 -0500 All, I have finally hit pay dirt in my quest for the original folded pendulum seismometer. The original instrument of this type was built in 1882 by Dr James Ewing. I believe that Dr Ewing was in Tokyo at the time. His instrument used a common pendulum coupled to an inverted pendulum so as to decrease the stability of the common pendulum. It appears to me that this was a two-axis instrument. Dr Ewing referred to it as a "Duplex pendulum" seismometer. History has it that a number, possibly ten of these instruments were placed at sites in Northern California and Nevada during 1887-1888. Seismographic observatories at Berkeley and Mount Hamilton had duplex pendulum seismometers. Perhaps an avid researcher in California might be able to actually find one of these instruments. Dr Ewing built many different seismometers and, along with Dr Thomas Gray, He seems to have been one of the founders of modern seismological instrumentation. The single axis instrument which I constructed is certainly not identical to the two-axis unit of Ewing, but it employs the same principals and is, in many ways similar to his duplex pendulum design. My best to all, Dave... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Folded pendulum history From: Jim ODonnell jimo17@........ Date: Mon, 31 Mar 2003 23:13:28 -0800 Hi Dave- Try looking in Bulletin of the Seismological Society of America. Vol. 59, No. 1, pp. 183-227. February, 1969 or go to: http://neic.usgs.gov/neis/seismology/history_seis.html to see what Ewing did. BTW- Dewey works in the same office as John Lahr- NEIC-Denver...Jim/UNLV The Early History of Seismometry (to 1900) by James Dewey and Perry Byerly Abstract The earliest seismoscope was invented in 132 A.D., by Chang Hêng. Seismoscopes of limited effectiveness were used by Bina and others in the eighteenth century. The middle nineteenth century saw the invention by Palmieri of a seismoscope to record the times of small earthquakes. A successful seismograph of low sensitivity was invented by Cecchi in 1875. British scientists at the College of Engineering, Tokyo, independently built seismographs in the 1880's. The British in Japan made many observations with their instruments and must be credited with first demonstrating the value to seismology of seismographic devices. Von Rebeur-Paschwitz obtained the first recording of a teleseism in 1889. In the next decade, investigators in Italy, Germany, and England studied the waves from distant earthquakes and constructed the first teleseismic travel-time charts. Wiechert introduced a seismometer with viscous damping in 1898. Theory seems to have been neglected in the early development of the seismograph. Theoretical studies of forced damped harmonic-oscillator seismographs were presented by Perry and Ayrton, and Lippmann, but these had little effect on the construction of seismographs. In the 1890's, the importance of tilt was much debated. By 1900, many seismologists had become convinced that the effect of tilting on seismograph response could usually be neglected. On Mon, 31 Mar 2003 17:20:58 -0500 "David H. Youden" writes: > All, > > I have finally hit pay dirt in my quest for the original folded > pendulum > seismometer. > > The original instrument of this type was built in 1882 by Dr James > Ewing. I > believe that Dr Ewing was in Tokyo at the time. His instrument used > a > common pendulum coupled to an inverted pendulum so as to decrease > the > stability of the common pendulum. It appears to me that this was a > two-axis > instrument. Dr Ewing referred to it as a "Duplex pendulum" > seismometer. > > History has it that a number, possibly ten of these instruments were > placed > at sites in Northern California and Nevada during 1887-1888. > Seismographic > observatories at Berkeley and Mount Hamilton had duplex pendulum > seismometers. > > Perhaps an avid researcher in California might be able to actually > find one > of these instruments. > > Dr Ewing built many different seismometers and, along with Dr Thomas > Gray, > He seems to have been one of the founders of modern seismological > instrumentation. > > The single axis instrument which I constructed is certainly not > identical > to the two-axis unit of Ewing, but it employs the same principals > and is, > in many ways similar to his duplex pendulum design. > > My best to all, > Dave... > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > >
Hi Dave- Try looking in   Bulletin = of the=20 Seismological Society of America. Vol. 59, No. 1, pp. 183-227. February= ,=20 1969  or go to: http://neic= ..usgs.gov/neis/seismology/history_seis.html to=20 see what Ewing did.
BTW- Dewey works in the same office as John Lahr-=20 NEIC-Denver...Jim/UNLV
 

The Early History of Seismometry (to = 1900)=20

by
James Dewey and Perry Byerly= =20
 
 

Abstract

The earliest seismoscope was invented in 132 A.D= .., by=20 Chang H=EAng. Seismoscopes of limited effectiveness were used by Bina and= others=20 in the eighteenth century. The middle nineteenth century saw the = invention by=20 Palmieri of a seismoscope to record the times of small earthquakes.

A successful seismograph of low sensitivity was = invented by=20 Cecchi in 1875. British scientists at the College of Engineering, Tokyo,= =20 independently built seismographs in the 1880's. The British in Japan made= many=20 observations with their instruments and must be credited with first=20 demonstrating the value to seismology of seismographic devices.

Von Rebeur-Paschwitz obtained the first recording of a= =20 teleseism in 1889. In the next decade, investigators in Italy, Germany, = and=20 England studied the waves from distant earthquakes and constructed the = first=20 teleseismic travel-time charts. Wiechert introduced a seismometer with = viscous=20 damping in 1898.

Theory seems to have been neglected in the early = development=20 of the seismograph. Theoretical studies of forced damped harmonic-= oscillator=20 seismographs were presented by Perry and Ayrton, and Lippmann, but these = had=20 little effect on the construction of seismographs. In the 1890's, the=20 importance of tilt was much debated. By 1900, many seismologists had = become=20 convinced that the effect of tilting on seismograph response could = usually be=20 neglected.

 
 

=
On Mon, 31 Mar 2003 17:20:58 -0500 "David H. Youden" <dyouden@.........> writes:
>= =20 All,
>
> I have finally hit pay dirt in my quest for the = original=20 folded
> pendulum
> seismometer.
>
> The = original=20 instrument of this type was built in 1882 by Dr James
> Ewing. I >=20 believe that Dr Ewing was in Tokyo at the time. His instrument used
>= ; a=20
> common pendulum coupled to an inverted pendulum so as to decrease= =20
> the
> stability of the common pendulum. It appears to me = that=20 this was a
> two-axis
> instrument. Dr Ewing referred to it = as a=20 "Duplex pendulum"
> seismometer.
>
> History has it = that a=20 number, possibly ten of these instruments were
> placed
> at = sites=20 in Northern California and Nevada during 1887-1888.
> Seismographic= =20
> observatories at Berkeley and Mount Hamilton had duplex pendulum=20
> seismometers.
>
> Perhaps an avid researcher in = California=20 might be able to actually
> find one
> of these=20 instruments.
>
> Dr Ewing built many different seismometers = and,=20 along with Dr Thomas
> Gray,
> He seems to have been one of = the=20 founders of modern seismological
> instrumentation.
>
>= The=20 single axis instrument which I constructed is certainly not
> = identical=20
> to the two-axis unit of Ewing, but it employs the same principals= =20
> and is,
> in many ways similar to his duplex pendulum=20 design.
>
> My best to all,
> Dave...
>
>=20 __________________________________________________________
>
>= =20 Public Seismic Network Mailing List (PSN-L)
>
> To leave this = list=20 email PSN-L-REQUEST@.............. with=20
> the body of the message (first line only): unsubscribe
> See= http://www.seismicnet.com/= maillist.html=20 for more information.
>
>
 
Subject: Quote of the day From: "Brady Romberg" bromberg@......... Date: Mon, 31 Mar 2003 20:34:47 -0700 Quote of the day: "You know the world is changing when the best rapper is a white guy, the best golfer is a black guy, the tallest guy in the NBA is Chinese, the Swiss hold the America's Cup, France is accusing the USA of arrogance and the Germans don't want to go to war!" __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Quote of the day - posting of OT material From: "Larry Cochrane" cochrane@.............. Date: Mon, 31 Mar 2003 19:53:16 -0800 I just send Brady a note telling him that his message was off topic and not allowed on this list. -Larry Cochrane Redwood City, PSN >From: "Brady Romberg" >Sent: Monday, March 31, 2003 7:34 PM >Subject: Quote of the day __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Folded pendulum history From: John or Jan Lahr johnjan@........ Date: Mon, 31 Mar 2003 22:44:39 -0700 Hi Dave, Thanks for finding this information! What do you think we should call this type of system? How about "Ewing duplex-pendulum seismometer?" Cheers, John At 03:20 PM 3/31/2003, you wrote: >All, > >I have finally hit pay dirt in my quest for the original folded pendulum >seismometer. > >The original instrument of this type was built in 1882 by Dr James Ewing. >I believe that Dr Ewing was in Tokyo at the time. His instrument used a >common pendulum coupled to an inverted pendulum so as to decrease the >stability of the common pendulum. It appears to me that this was a >two-axis instrument. Dr Ewing referred to it as a "Duplex pendulum" >seismometer. > >History has it that a number, possibly ten of these instruments were >placed at sites in Northern California and Nevada during 1887-1888. >Seismographic observatories at Berkeley and Mount Hamilton had duplex >pendulum seismometers. > >Perhaps an avid researcher in California might be able to actually find >one of these instruments. > >Dr Ewing built many different seismometers and, along with Dr Thomas Gray, >He seems to have been one of the founders of modern seismological >instrumentation. > >The single axis instrument which I constructed is certainly not identical >to the two-axis unit of Ewing, but it employs the same principals and is, >in many ways similar to his duplex pendulum design. > >My best to all, >Dave... > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Seismic Display From: "Connie and Jim Lehman" lehmancj@........... Date: Tue, 1 Apr 2003 17:20:45 -0500 PSN-friends, Saturday Mar. 29, I exhibited the JMU, "Lehman" long = period sensor at the Nat. Assoc. of Geoscience Teachers, & Nat. Earth = Science Teachers Assoc. Share-a-thon in Philadelphia. An interesting = "Earth Science" Day--- An enjoyable occasion--a number of inquiries. I = as always, give a big promotion to the PSN and its resources/links, = etc. Perhaps there will be some new people moving into the world of = real-time seismic activities. Best wishes, Jim Lehman
PSN-friends,  = Saturday Mar.=20 29, I exhibited the JMU, "Lehman" long period sensor at the Nat. Assoc. = of=20 Geoscience Teachers, & Nat. Earth Science Teachers  Assoc. = Share-a-thon=20 in Philadelphia.  An interesting "Earth Science" Day--- An = enjoyable=20 occasion--a number of inquiries.  I as always,  give a big = promotion=20 to the PSN and its resources/links, etc.  Perhaps there will be = some new=20 people moving into the world of real-time seismic = activities.
          &nbs= p;            = ;            =    =20 Best wishes, Jim Lehman
Subject: Re: Folded pendulum history From: "David H. Youden" dyouden@......... Date: Wed, 02 Apr 2003 06:02:16 -0500 Hi John, Well, it's not exactly going to sell a lot of seismometers, but it does give credit where credit is due. It will probably be shortened to EDP Seismometer, but what the heck. It's certainly OK with me, and since I haven't heard from anyone at UWA recently, let's go with it. So "Ewing Duplex Pendulum Seismometer" it is, unless someone chimes in with a major dissenting opinion. Dave... PS 80 degrees here in North Carolina today> Spring has sprung! At 10:44 PM 3/31/03 -0700, you wrote: >Hi Dave, > >Thanks for finding this information! What do you think we should call this >type of system? How about "Ewing duplex-pendulum seismometer?" > >Cheers, >John > >At 03:20 PM 3/31/2003, you wrote: >>All, >> >>I have finally hit pay dirt in my quest for the original folded pendulum >>seismometer. >> >>The original instrument of this type was built in 1882 by Dr James Ewing. >>I believe that Dr Ewing was in Tokyo at the time. His instrument used a >>common pendulum coupled to an inverted pendulum so as to decrease the >>stability of the common pendulum. It appears to me that this was a >>two-axis instrument. Dr Ewing referred to it as a "Duplex pendulum" >>seismometer. >> >>History has it that a number, possibly ten of these instruments were >>placed at sites in Northern California and Nevada during 1887-1888. >>Seismographic observatories at Berkeley and Mount Hamilton had duplex >>pendulum seismometers. >> >>Perhaps an avid researcher in California might be able to actually find >>one of these instruments. >> >>Dr Ewing built many different seismometers and, along with Dr Thomas >>Gray, He seems to have been one of the founders of modern seismological >>instrumentation. >> >>The single axis instrument which I constructed is certainly not identical >>to the two-axis unit of Ewing, but it employs the same principals and is, >>in many ways similar to his duplex pendulum design. >> >>My best to all, >>Dave... >> >>__________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email PSN-L-REQUEST@.............. with the body of >>the message (first line only): unsubscribe >>See http://www.seismicnet.com/maillist.html for more information. > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: About time issue From: Richard Gagnon richg_1998@......... Date: Thu, 3 Apr 2003 22:32:05 -0800 (PST) Hello Group I have started using About Time for time correction but it always corrects my computer clock exactly one hour fast. I do not have the daylight savings time option selected in my computer. I have GMT, Greenwich, time zone selected. I have a pentium II, W98SE and I am on a cable modem through my local cable provider. I live in Massachusetts. I connect to U.S. Naval Observatory using SNTP when I use About Time. I can get the proper time if I select the -1 hour Cape Verde selection in my computer clock time zone. If the answer is supposed to be obvious, obviously I have missed it. Thank you. Richard __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: "a.rodriguez" stuff@................. Date: Fri, 4 Apr 2003 06:28:42 -0500 Hello Richard, If you are using WXP or W2000 try turning off the windows time service. angel Friday, April 4, 2003, 1:32:05 AM, you wrote: RG> Hello Group RG> I have started using About Time for time correction but it always corrects my RG> computer clock exactly one hour fast. I do not have the daylight savings time RG> option selected in my computer. I have GMT, Greenwich, time zone selected. I RG> have a pentium II, W98SE and I am on a cable modem through my local cable RG> provider. I live in Massachusetts. I connect to U.S. Naval Observatory using RG> SNTP when I use About Time. I can get the proper time if I select the -1 hour RG> Cape Verde selection in my computer clock time zone. If the answer is supposed RG> to be obvious, obviously I have missed it. Thank you. RG> Richard __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: Richard Gagnon richg_1998@......... Date: Fri, 4 Apr 2003 08:08:05 -0800 (PST) Hello Angel I am using W98SE Richard --- "a.rodriguez" wrote: > Hello Richard, > > If you are using WXP or W2000 try turning off the windows time > service. > > angel > > Friday, April 4, 2003, 1:32:05 AM, you wrote: > > RG> Hello Group > > RG> I have started using About Time for time correction but it always > corrects my > RG> computer clock exactly one hour fast. I do not have the daylight savings > time > RG> option selected in my computer. I have GMT, Greenwich, time zone > selected. I > RG> have a pentium II, W98SE and I am on a cable modem through my local cable > RG> provider. I live in Massachusetts. I connect to U.S. Naval Observatory > using > RG> SNTP when I use About Time. I can get the proper time if I select the -1 > hour > RG> Cape Verde selection in my computer clock time zone. If the answer is > supposed > RG> to be obvious, obviously I have missed it. Thank you. > > RG> Richard > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re[2]: About time issue From: "a.rodriguez" stuff@................. Date: Fri, 4 Apr 2003 12:38:05 -0500 Hello Richard, Are you sure that you have the saving time thing unchecked? Do it in the control panel with the date and time applet. I don't use "about time" , I use Tardis and it also has a box to uncheck. Make sure that "about time" is not trying to second guess windows. regards, angel Friday, April 4, 2003, 11:08:05 AM, you wrote: RG> Hello Angel RG> I am using W98SE RG> Richard __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Re[2]: About time issue From: Richard Gagnon richg_1998@......... Date: Fri, 4 Apr 2003 09:54:25 -0800 (PST) Yes, it is unchecked. Richard --- "a.rodriguez" wrote: > Hello Richard, > > Are you sure that you have the saving time thing unchecked? > > Do it in the control panel with the date and time applet. > > I don't use "about time" , I use Tardis and it also has a box to > uncheck. Make sure that "about time" is not trying to second guess > windows. > > regards, > > angel > > Friday, April 4, 2003, 11:08:05 AM, you wrote: > > RG> Hello Angel > > RG> I am using W98SE > > RG> Richard > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Cap's KS36000 Seismometer From: Karl Cunningham karlc@.......... Date: Fri, 04 Apr 2003 13:53:22 -0800 Hello All -- Most of you are probably aware that some month's ago Casper Hossfield, a member of this list, passed away. Cap had a Geotech KS36000 seismometer. His family wants to clean up his property and needs to get rid of the seismometer and associated documentation, hardware, and electronics. They understand the value of the instrument and want to see it go to a good home. As Cap's family doesn't want to do any more legwork than necessary regarding the seismometer, I volunteered to try to find a taker for it. The seismometer is a Teledyne-Geotech KS36000 bore-hole broadband 3-axis seismometer. It is intended to be lowered into a deep well and is housed in a 5-inch diameter stainless-steel tube about 8 feet long. It weighs about 180 pounds. This is not an instrument for casual use. It is a research-grade instrument which will not operate unless mounted vertically and can be damaged if shocked in excess of 2G. Its intended use was down a 100-meter-deep well, although it can be made to work in a post hole. It is somewhat temperature sensitive but the main reason for the deep hole is to reduce the effects of surface noise. There were approximately 40 of these seismometers surplus at the USGS in Alguquerque, which were given away to researchers, universities, and amateur seismologists. Cap was one of the lucky ones to get one. The KS36000 requires special digital codes be sent to unlock the masses and configure the unit. The outputs are analog. The specifications list very good performance -- a noise floor of about 21 orders of magnitude below gravity. I believe Cap had a Test Set/Controller, which is used to send the required digital codes. Other methods can be used to do this, such as a computer sound card. I think Cap had a manual for the instrument, which is quite thorough and contains setup and maintenance information. The seismometer is located at Cap's house near New Milford, New York, and is offered as-is, where-is. It is in the woods which is currently about a foot of snow on the ground. When the snow melts (about a month), Cap's family would like it to be picked up. It probably will require three or four people to safely get it into a truck. I don't know if Cap's family will be able to help with this part. One further caveat: When the USGS gave the seismometer to Cap, he signed a statement that he would never sell it or otherwise get money for it. Whomever gets it at this point will have to sign a statement to that effect, which will be forwarded to the USGS in Albuquerque. If anyone is interested in the seismometer, please email me off the list. I can supply more details about its construction and operation if needed. If there is no response within a week or two, I will contact the USGS to see if they can find someone. Regards. Karl Cunningham La Mesa, CA. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: Frank Condon frankcnd@.......... Date: Fri, 04 Apr 2003 22:34:43 +0000 At 08:08 AM 4/4/2003 -0800, you wrote: >Hello Angel > >I am using W98SE > >Richard > > > > >--- "a.rodriguez" wrote: > > Hello Richard, > > > > If you are using WXP or W2000 try turning off the windows time > > service. > > > > angel > > > > Friday, April 4, 2003, 1:32:05 AM, you wrote: > > > > RG> Hello Group > > > > RG> I have started using About Time for time correction but it always > > corrects my > > RG> computer clock exactly one hour fast. I do not have the daylight > savings > > time > > RG> option selected in my computer. I have GMT, Greenwich, time zone > > selected. I > > RG> have a pentium II, W98SE and I am on a cable modem through my local > cable > > RG> provider. I live in Massachusetts. I connect to U.S. Naval Observatory > > using > > RG> SNTP when I use About Time. I can get the proper time if I select > the -1 > > hour > > RG> Cape Verde selection in my computer clock time zone. If the answer is > > supposed > > RG> to be obvious, obviously I have missed it. Thank you. > > > > RG> Richard > > > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > > >__________________________________________________ >Do you Yahoo!? >Yahoo! Tax Center - File online, calculators, forms, and more >http://tax.yahoo.com >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with >the body of the message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. Hi Richard: Try setting your time zone to Morroco. Great Britain goes on daylight savings time the first Sunday in April. Morroco stays at UTC all of the time. Regards, Frank Condon "Experimental data collected and analyzed for its hidden message is considered preliminary until proven otherwise" __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cap's KS36000 Seismometer From: hammond hammond@........... Date: Fri, 04 Apr 2003 16:29:01 -0900 Karl and other PSN folk, I'm very interested in getting Cap's KS36000 seismometer. I have an abandoned 300+ foot dry well in bedrock which would be ideal for the instrument. The problem is logistics: I'm in Fairbanks, Alaska and the KS36000 is in New York. Is there anyone on the list who might be willing to help with getting it ready to ship? That is, if I'm the chosen recipient.... thanks, Bob Hammond Public Seismic Network - Alaska http://apsn.awcable.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cap's KS36000 Seismometer From: ACole65464@....... Date: Fri, 4 Apr 2003 21:49:12 EST A general question for anyone who recieved an old KS36000 unit, have you recorded any meaningful data from it yet? Allan Coleman __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: Richard Gagnon richg_1998@......... Date: Fri, 4 Apr 2003 20:53:32 -0800 (PST) --- Frank Condon wrote: > Hi Richard: > > Try setting your time zone to Morroco. Great Britain goes on daylight > savings time the first Sunday in April. Morroco stays at UTC all of the time. > > Regards, > > Frank Condon > "Experimental data collected and analyzed for its hidden message is > considered preliminary until proven otherwise" Hi Frank That works. My mistake, I thought UTC never changed. Richard __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: "Larry Cochrane" cochrane@.............. Date: Fri, 4 Apr 2003 21:00:34 -0800 UTC does not change between daylight savings time and standard time. Sounds like a problem with About time.... -Larry Cochrane Redwood City, PSN ----- Original Message ----- From: "Richard Gagnon" To: Sent: Friday, April 04, 2003 8:53 PM Subject: Re: About time issue > --- Frank Condon wrote: > > > Hi Richard: > > > > Try setting your time zone to Morroco. Great Britain goes on daylight > > savings time the first Sunday in April. Morroco stays at UTC all of the time. > > > > Regards, > > > > Frank Condon > > "Experimental data collected and analyzed for its hidden message is > > considered preliminary until proven otherwise" > > Hi Frank > > That works. My mistake, I thought UTC never changed. > > Richard > > __________________________________________________ > Do you Yahoo!? > Yahoo! Tax Center - File online, calculators, forms, and more > http://tax.yahoo.com > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. > __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: About time issue From: Richard Gagnon richg_1998@......... Date: Fri, 4 Apr 2003 22:33:51 -0800 (PST) Hi Larry I wondered about that. The About Time site says do not send Emails inquiring about issues so I thought I would try the psn since I plan to have a Leman operational some day. I will go with a gps and your a/d board in the future. I would hope to also have 24 hour time in the future. Richard Thank you. --- Larry Cochrane wrote: > UTC does not change between daylight savings time and standard time. Sounds > like a problem with About time.... > > -Larry Cochrane > Redwood City, PSN > > ----- Original Message ----- > From: "Richard Gagnon" > To: > Sent: Friday, April 04, 2003 8:53 PM > Subject: Re: About time issue > > > > --- Frank Condon wrote: > > > > > Hi Richard: > > > > > > Try setting your time zone to Morroco. Great Britain goes on daylight > > > savings time the first Sunday in April. Morroco stays at UTC all of the > time. > > > > > > Regards, > > > > > > Frank Condon > > > "Experimental data collected and analyzed for its hidden message is > > > considered preliminary until proven otherwise" > > > > Hi Frank > > > > That works. My mistake, I thought UTC never changed. > > > > Richard > > > > __________________________________________________ > > Do you Yahoo!? > > Yahoo! Tax Center - File online, calculators, forms, and more > > http://tax.yahoo.com > > __________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email PSN-L-REQUEST@.............. with > > the body of the message (first line only): unsubscribe > > See http://www.seismicnet.com/maillist.html for more information. > > > > > __________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email PSN-L-REQUEST@.............. with > the body of the message (first line only): unsubscribe > See http://www.seismicnet.com/maillist.html for more information. __________________________________________________ Do you Yahoo!? Yahoo! Tax Center - File online, calculators, forms, and more http://tax.yahoo.com __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: A Free Mass seismometer From: "David H. Youden" dyouden@......... Date: Sat, 05 Apr 2003 07:45:52 -0500 All, I have been thinking ( a dangerous thing, to be sure) about a seismometer that has no natural frequency. Perhaps (probably) this idea is not new, but never-the-less, here it is: Imagine, if you will, a stack of, say 1" diameter aluminum tubes about 10 inches long. There are 9 tubes, two on the bottom, three in the next layer up, and four in the top layer. These tubes are stacked like bowling pins with the head pin missing. Now imagine that, on the sides and top of this structure there are pieces of glass so that the sides are smooth, relatively accurate, surfaces. The top is not so important, and might be a piece of aluminum plate instead of glass. Now fill the tubes with something which has mass, perhaps a mixture of sand and epoxy (search the web for "Granitan" and you'll get the idea). Now comes the hard part. Imagine this assembly of tubes supported on four circular slices of aluminum arranged two on each side, flat against the outward sloping surfaces of the glass plates. The outside flat surfaces of the aluminum disks. have countersunk holes that hold balls so that the disks can align themselves with the glass surfaces. The balls, in turn are located in stationary mounting plates that are attached to the non-moving base of the structure. The surface of the aluminum disks which face the glass is recessed about .001" leaving a smooth, lapped rim about 0.100" wide touching the glass. In the center of the recess is a small hole, say about .062" which is cross drilled to a small air fitting, I think the common size is 10-32 (Look in an aquarium shop for this.) All four aluminum disks are the same, and they are connected together with aquarium air hose. (The more flexible, the better.) This hose is also connected to an aquarium air pump. When the pump is turned on - Voila! The tube structure (The free mass) will rise slightly on an air film which will form between the aluminum disks and the glass, and the mass will float freely, with zero static coefficient of friction. In fact, it will slide off of the air bearings and fall on the floor if you are not careful. Now imagine this free mass with a voice coil or other driver attached to it at one end, and the transducer of your choice attached to it at the other. Imagine also, a set of leveling screws between the base and good old mother earth. There are enhancements possible, including an air receiver and filter to reduce air pressure pulsations and dirt (although the pressure pulsations are far above our frequency of interest, and the mass can't follow them anyway.), and a temperature control system. (Always include a temperature control system. Always.) Now the caveats. I have not built the system just described, but I have built many air bearing devices, so I'm pretty sure of my technology here. The tube and glass structure is just my way of building an accurate prismatic shape in my garage. Other approaches are possible. Please jump in and critique my ideas here. You can't hurt my feelings, and the device doesn't exist, so it can be changed with a thought. I hereby declare the season open. Dave... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A Free Mass seismometer From: beezaur beezaur@.......... Date: Sat, 05 Apr 2003 09:45:03 -0800 Dave, Is there any force keeping the free mass centered? Air flow changes? If so then you are back to having a natural period. I'm not a fluids guy, but I wonder if small scale turbulence in air flow would cause an unpredictable wandering and the fall to the floor you mention. Is there an active way to keep the thing centered, maybe radiation pressure from lasers? Any active correction could be measured and removed from data. Scott David H. Youden wrote: > All, > > I have been thinking ( a dangerous thing, to be sure) about a > seismometer that has no natural frequency. Perhaps (probably) this idea > is not new, but never-the-less, here it is: > > Imagine, if you will, a stack of, say 1" diameter aluminum tubes . . . -- A day without math is like a day without sunshine. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A Free Mass seismometer From: ChrisAtUpw@....... Date: Sat, 5 Apr 2003 15:34:04 EST In a message dated 05/04/03, dyouden@......... writes: > I have been thinking about a seismometer that has no natural frequency. > Hi Dave, > Imagine, if you will, a stack of, say 1" diameter aluminum tubes about 10 > inches long. There are 9 tubes, two on the bottom, three in the next layer > I would rather not thank you! Why make it extremely complicated, when you can make it dead simple? Take a circular piece of plate glass and drill a hole in the middle for the air supply. Support the outside edges on a circular metal structure with three levelling screws. Use another, but smaller diameter sheet of plate glass or of Al etc. more or less centrally placed. This will need to have the bottom surface modified, possibly by sticking on foil or by etching, to give either a circular or a clover leaf shaped air bearing. Fit the top of the plate with two pairs of Maxwell coil + magnet force actuators, at right angles and a shadow type capacitative distance transducer and you might be 'in business'! See http://physics.mercer.edu/petepag/tutorial.html You might need to lap polish the two glass plates together with fine carborundum and rouge, rather like you do when lapping optical flats, to get a near perfect fit. It is usually inviting trouble to put unscreened magnets on a seismic mass, but you could probably get away with small opposed magnet pairs. You might need an additional pair at some point on the periphery of the disk, to prevent rotation. In operation, the top disk is floated using the air supply at the centre of the base plate. There is no wiring or tube connections needed for the armature disk. The distance transducer measures the deflections in the X and Y directions and feeds back PID signals to the coil pairs to keep the plate centralised. You need maybe 1 to 2 lb mass total to keep down the inherent noise. > The surface of the aluminum disks which face the glass is recessed about > .001" leaving a smooth, lapped rim about 0.100" wide touching the glass. In > the centre of the recess is a small hole, say about .062" which is cross > drilled to a small air fitting, I think the common size is 10-32 (Look in > an aquarium shop for this.) This hose is also connected to an aquarium air > pump. When the pump is turned on - Voila! The free mass will rise slightly > on an air film which will form between the > plates, and the mass will float freely, with zero static coefficient of > Can you give us references for the design of air bearings, please? I know that they are designed as overdamped pneumatic LCR circuits, but I don't have any formulae, etc. They will need very careful design. While air bearings have zero static friction, they may have small dynamic forces. We used to use a glass plate surrounded by spring wires and heavy metal 'pucks' to demonstrate the laws of mechanics. Each puck had a gas tight chamber which was filled with dry ice. This slowly sublimated and provided the gas flow for the bearing underneath. However, there was always a very slight 'dither' on them. I do not know if this was due to varying gas pressure, to inadequate sublimation control, to poor bearing design, to variations in the surface of the glass plate, or to turbulent flow. > There are enhancements possible, including an air receiver and filter to > reduce air pressure pulsations and dirt (although the pressure pulsations > are far above our frequency of interest, and the mass can't follow them > anyway) and a temperature control system. (Always include a temperature > You will need a very stable and clean air supply. The air bearings will need to be run with laminar flow, or turbulence noise and random forces will be generated. If the rig could be totally enclosed, the air could be filtered and circulated. The pumping pressure fluctuations will need a considerable amount of smoothing. The mass will tend to follow pressure fluctuations, whatever the frequency - it depends directly on the gas pressure to elevate it! I would be concerned about possible transitions from laminar to turbulent gas flow in the bearings. You might need to use a multiple tube peristaltic pump. One reason why professional systems do not often use temperature control, is that they are usually buried / installed below ground level. Once you get below about 1 m depth in most rock formations, the daily temperature change is reduced to milli degree levels. It is very difficult indeed = expensive to get anywhere near this sort of stability using active thermostatic control. > I hereby declare the season open. It would be an interesting experiment to try. You might initially use simple differential optical sensors. A pair of VTD34 7.4 sq mm photodiodes and an OPA2134 opamp can give about 20 nm resolution at 10 Hz. If this works, you can invest in capacitative transducers which give better than 1 nm resolution. Regards, Chris Chapman In a message dated 05/04/= 03, dyouden@......... writes:

I have been thinking about=20= a seismometer that has no natural frequency. Perhaps (probably) this idea is= not new, but never-the-less, here it is:


Hi Dave,

Imagine, if you will, a sta= ck of, say 1" diameter aluminum tubes about 10 inches long. There are 9 tube= s, two on the bottom, three in the next layer up, and four in the top layer.= ........


      I would rather not thank you! Why m= ake it extremely complicated, when you can make it dead simple?

      Take a circular piece of plate glas= s and drill a hole in the middle for the air supply. Support the outside edg= es on a circular metal structure with three levelling screws. Use another, b= ut smaller diameter sheet of plate glass or of Al etc. more or less centrall= y placed. This will need to have the bottom surface modified, possibly by st= icking on foil or by etching, to give either a circular or a clover leaf sha= ped air bearing. Fit the top of the plate with two pairs of Maxwell coil + m= agnet force actuators, at right angles and a shadow type capacitative distan= ce transducer and you might be 'in business'! See http://physics.mercer.edu/petepag/tutoria= l.html=20
      You might need to lap polish the tw= o glass plates together with fine carborundum and rouge, rather like you do=20= when lapping optical flats, to get a near perfect fit. It is usually invitin= g trouble to put unscreened magnets on a seismic mass, but you could probabl= y get away with small opposed magnet pairs. You might need an additional pai= r at some point on the periphery of the disk, to prevent rotation.=20

      In operation, the top disk is float= ed using the air supply at the centre of the base plate. There is no wiring=20= or tube connections needed for the armature disk. The distance transducer me= asures the deflections in the X and Y directions and feeds back PID signals=20= to the coil pairs to keep the plate centralised. You need maybe 1 to 2 lb ma= ss total to keep down the inherent noise.
=20
The surface of the aluminum= disks which face the glass is recessed about .001" leaving a smooth, lapped= rim about 0.100" wide touching the glass. In the centre of the recess is a=20= small hole, say about .062" which is cross drilled to a small air fitting, I= think the common size is 10-32 (Look in an aquarium shop for this.) This ho= se is also connected to an aquarium air pump. When the pump is turned on - V= oila! The free mass will rise slightly on an air film which will form betwee= n the=20
plates, and the mass will float freely, with zero static coefficient of=20= friction.


      Can you give us references for the=20= design of air bearings, please? I know that they are designed as overdamped=20= pneumatic LCR circuits, but I don't have any formulae, etc. They will need v= ery careful design. While air bearings have zero static friction, they may h= ave small dynamic forces.=20
      We used to use a glass plate surrou= nded by spring wires and heavy metal 'pucks' to demonstrate the laws of mech= anics. Each puck had a gas tight chamber which was filled with dry ice. This= slowly sublimated and provided the gas flow for the bearing underneath. How= ever, there was always a very slight 'dither' on them. I do not know if this= was due to varying gas pressure, to inadequate sublimation control, to poor= bearing design, to variations in the surface of the glass plate, or to turb= ulent flow.   

There are enhancements poss= ible, including an air receiver and filter to reduce air pressure pulsations= and dirt (although the pressure pulsations are far above our frequency of i= nterest, and the mass can't follow them anyway) and a temperature control sy= stem. (Always include a temperature control system. Always.)


      You will need a very stable and cle= an air supply. The air bearings will need to be run with laminar flow, or tu= rbulence noise and random forces will be generated. If the rig could be tota= lly enclosed, the air could be filtered and circulated. The pumping pressure= fluctuations will need a considerable amount of smoothing. The mass will te= nd to follow pressure fluctuations, whatever the frequency - it depends dire= ctly on the gas pressure to elevate it! I would be concerned about possible=20= transitions from laminar to turbulent gas flow in the bearings. You might ne= ed to use a multiple tube peristaltic pump.

      One reason why professional systems= do not often use temperature control, is that they are usually buried / ins= talled below ground level. Once you get below about 1 m depth in most rock f= ormations, the daily temperature change is reduced to milli degree levels. I= t is very difficult indeed =3D expensive to get anywhere near this sort of s= tability using active thermostatic control.      &n= bsp; 

I hereby declare the season= open.
      It would be an interesting experime= nt to try. You might initially use simple differential optical sensors. A pa= ir of VTD34 7.4 sq mm photodiodes and an OPA2134 opamp can give about 20 nm=20= resolution at 10 Hz. If this works, you can invest in capacitative transduce= rs which give better than 1 nm resolution.

      Regards,

      Chris Chapman Subject: Re: Cap's KS36000 Seismometer From: John or Jan Lahr johnjan@........ Date: Sat, 05 Apr 2003 17:23:27 -0700 Hi Bob, Glad to see that you're keeping busy in seismology! I guess once it's in your blood, there's no way to avoid it. Good luck with the KS36000. I understand it's not easy to get one going and that the manuals are critical. I wonder if any of the PSN members who got one managed to get it running? Cheers, John At 06:29 PM 4/4/2003, you wrote: >Karl and other PSN folk, > >I'm very interested in getting Cap's KS36000 seismometer. I have an abandoned >300+ foot dry well in bedrock which would be ideal for the instrument. > >The problem is logistics: I'm in Fairbanks, Alaska and the KS36000 is in >New York. >Is there anyone on the list who might be willing to help with getting it >ready to ship? >That is, if I'm the chosen recipient.... > >thanks, > >Bob Hammond >Public Seismic Network - Alaska >http://apsn.awcable.com > >__________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email PSN-L-REQUEST@.............. with the body of the >message (first line only): unsubscribe >See http://www.seismicnet.com/maillist.html for more information. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Cap's KS36000 Seismometer From: hammond hammond@........... Date: Sat, 05 Apr 2003 16:29:02 -0900 John, As my good friend (who runs the Montana EQ Network) said: "You can take the guy out of seismology but you can't take the seismology out of the guy." Yes, I'd be curious to know if any of the KS36000 instruments given away by ASL are running, either with PSN members or university groups. Acquiring Cap's instrument is most likely going to be too much of a logistical problem for me to solve. And even if I did get it, I suspect it would be damaged in shipping from NY to AK. That is, if I could afford the shipping.... But, it would be cool to have one operational. It would fit right in with my LASA instrument. regards, Bob At 03:23 PM 4/5/2003, you wrote: >Hi Bob, > >Glad to see that you're keeping busy in seismology! I guess once it's in >your blood, there's no way to avoid it. > >Good luck with the KS36000. I understand it's not easy to get one going and >that the manuals are critical. I wonder if any of the PSN members who got one >managed to get it running? > >Cheers, >John > >At 06:29 PM 4/4/2003, you wrote: >>Karl and other PSN folk, >> >>I'm very interested in getting Cap's KS36000 seismometer. I have an >>abandoned >>300+ foot dry well in bedrock which would be ideal for the instrument. >> >>The problem is logistics: I'm in Fairbanks, Alaska and the KS36000 is in >>New York. >>Is there anyone on the list who might be willing to help with getting it >>ready to ship? >>That is, if I'm the chosen recipient.... >> >>thanks, >> >>Bob Hammond >>Public Seismic Network - Alaska >>http://apsn.awcable.com >> >>__________________________________________________________ __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A Free Mass seismometer From: "David H. Youden" dyouden@......... Date: Sun, 06 Apr 2003 06:18:00 -0400 Scott,

At 09:45 AM 4/5/03 -0800, you wrote:
Dave,

Is there any force keeping the free mass centered?  Air flow changes? If so then you are back to having a natural period.

There is no centering force other than that generated by whatever driver is installed for force feedback. Sometimes the air bearings can produce a slight decentering force, but this looks like tilt and can be compensated.


I'm not a fluids guy, but I wonder if small scale turbulence in air flow would cause an unpredictable wandering and the fall to the floor you mention.  Is there an active way to keep the thing centered, maybe radiation pressure from lasers?  Any active correction could be measured and removed from data.

The air flow is laminar, and measurements that I have made on similar, far more expensive systems indicate no change in the noise at the picometer level when the bearings are turned on. The fall to the floor is caused by tilt, as these things are, as you can imagine, extremely sensitive to tilt.


Scott

David H. Youden wrote:
All,
I have been thinking ( a dangerous thing, to be sure) about a seismometer that has no natural frequency. Perhaps (probably) this idea is not new, but never-the-less, here it is:
Imagine, if you will, a stack of, say 1" diameter aluminum tubes . . ..
--
A day without math is like a day without sunshine.

__________________________________________________________

Public Seismic Network Mailing List (PSN-L)

http://www.seismicnet.com/maillist.html for more information.
Subject: Re: A Free Mass seismometer From: "David H. Youden" dyouden@......... Date: Sun, 06 Apr 2003 06:30:30 -0400 Chris,

I guess complexity depends upon personal viewpoint to some degree. What you have described seems complex to me. I have built systems similar to what you describe and the complexity springs from having to prevent rotation.

My stack of tubes originates from the challenge of making a relatively accurate prismatic shape without resorting to machine tools, which most of us don't have. Commercial tubing is pretty repeatable stuff, although not especially accurate.

At any rate, it doesn't matter, make what is easy for you.

I have built a commercial system, with a moving mass of about 10 Kg. (It cost about $800,000) with 0.3 nanometer laser position feedback. I have never thought of looking for seismic effects on this device, but I'll bet that they are there. That particular device is used for metrology, and has an overall position accuracy of less than 10 nanometers.

The noise from air bearings is low enough so that I have been able to machine 10 Angstrom RMS surface finishes in aluminum on these bearings.

As for web references, I don't know of any at the moment, but I'll look. There is not much published on the topic, but I'll try to generate a reading list in the next couple of days.

At 03:34 PM 4/5/03 -0500, you wrote:
In a message dated 05/04/03, dyouden@......... writes:

I have been thinking about a seismometer that has no natural frequency. Perhaps (probably) this idea is not new, but never-the-less, here it is:


Hi Dave,

Imagine, if you will, a stack of, say 1" diameter aluminum tubes about 10 inches long. There are 9 tubes, two on the bottom, three in the next layer up, and four in the top layer........


      I would rather not thank you! Why make it extremely complicated, when you can make it dead simple?

      Take a circular piece of plate glass and drill a hole in the middle for the air supply. Support the outside edges on a circular metal structure with three levelling screws. Use another, but smaller diameter sheet of plate glass or of Al etc. more or less centrally placed. This will need to have the bottom surface modified, possibly by sticking on foil or by etching, to give either a circular or a clover leaf shaped air bearing. Fit the top of the plate with two pairs of Maxwell coil + magnet force actuators, at right angles and a shadow type capacitative distance transducer and you might be 'in business'! See http://physics.mercer.edu/petepag/tutorial.html
      You might need to lap polish the two glass plates together with fine carborundum and rouge, rather like you do when lapping optical flats, to get a near perfect fit. It is usually inviting trouble to put unscreened magnets on a seismic mass, but you could probably get away with small opposed magnet pairs. You might need an additional pair at some point on the periphery of the disk, to prevent rotation.

      In operation, the top disk is floated using the air supply at the centre of the base plate. There is no wiring or tube connections needed for the armature disk. The distance transducer measures the deflections in the X and Y directions and feeds back PID signals to the coil pairs to keep the plate centralised. You need maybe 1 to 2 lb mass total to keep down the inherent noise.

The surface of the aluminum disks which face the glass is recessed about .001" leaving a smooth, lapped rim about 0.100" wide touching the glass. In the centre of the recess is a small hole, say about .062" which is cross drilled to a small air fitting, I think the common size is 10-32 (Look in an aquarium shop for this.) This hose is also connected to an aquarium air pump. When the pump is turned on - Voila! The free mass will rise slightly on an air film which will form between the
plates, and the mass will float freely, with zero static coefficient of friction.


      Can you give us references for the design of air bearings, please? I know that they are designed as overdamped pneumatic LCR circuits, but I don't have any formulae, etc. They will need very careful design. While air bearings have zero static friction, they may have small dynamic forces.
      We used to use a glass plate surrounded by spring wires and heavy metal 'pucks' to demonstrate the laws of mechanics. Each puck had a gas tight chamber which was filled with dry ice. This slowly sublimated and provided the gas flow for the bearing underneath. However, there was always a very slight 'dither' on them. I do not know if this was due to varying gas pressure, to inadequate sublimation control, to poor bearing design, to variations in the surface of the glass plate, or to turbulent flow.   

There are enhancements possible, including an air receiver and filter to reduce air pressure pulsations and dirt (although the pressure pulsations are far above our frequency of interest, and the mass can't follow them anyway) and a temperature control system. (Always include a temperature control system. Always.)


      You will need a very stable and clean air supply. The air bearings will need to be run with laminar flow, or turbulence noise and random forces will be generated. If the rig could be totally enclosed, the air could be filtered and circulated. The pumping pressure fluctuations will need a considerable amount of smoothing. The mass will tend to follow pressure fluctuations, whatever the frequency - it depends directly on the gas pressure to elevate it! I would be concerned about possible transitions from laminar to turbulent gas flow in the bearings. You might need to use a multiple tube peristaltic pump.

      One reason why professional systems do not often use temperature control, is that they are usually buried / installed below ground level. Once you get below about 1 m depth in most rock formations, the daily temperature change is reduced to milli degree levels. It is very difficult indeed = expensive to get anywhere near this sort of stability using active thermostatic control.        

I hereby declare the season open.


      It would be an interesting experiment to try. You might initially use simple differential optical sensors. A pair of VTD34 7.4 sq mm photodiodes and an OPA2134 opamp can give about 20 nm resolution at 10 Hz. If this works, you can invest in capacitative transducers which give better than 1 nm resolution.

      Regards,

      Chris Chapman
Subject: A2DMAX and Radiosky pipe From: "David H. Youden" dyouden@......... Date: Sun, 06 Apr 2003 06:41:10 -0400 All, I said earlier that I had ordered the subject material and would report on my experiences. Here's the report. I ordered the complete kit of parts for this device, but elected to use the free (single channel) version of the software until I had things working. Unfortunately that has never happened. The kit arrived OK, and was simple enough to build. Once built, however, it simply did not work. I have tried three different computers, reconfigured parallel ports until I'm sick of it, and fussed over every aspect of the rig. I have never lost an integrated circuit to static, and I don't believe that this one has died that way. E-mail to Radiosky publishing is returned with an unable to deliver message. So there you have it. A total failure and a waste of $50. My advice: Don't waste your money. Dave... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A Free Mass seismometer From: ChrisAtUpw@....... Date: Sun, 6 Apr 2003 12:38:40 EDT In a message dated 06/04/03, dyouden@......... writes: Hi Dave, Thanks for the reply. > I guess complexity depends upon personal viewpoint to some degree. What you > have described seems complex to me. I have built systems similar to what > you describe and the complexity springs from having to prevent rotation. ? It is two flat sheets of glass with 4 pairs of small magnets and two strips of metal mounted horizontally on top of the top sheet --- it's not too complicated! I would expect it to be rather easier to prevent rotation than to do the linear positioning. > My stack of tubes originates from the challenge of making a relatively > accurate prismatic shape without resorting to machine tools, which most of > us don't have. Commercial tubing is pretty repeatable stuff, although not > especially accurate. I have very considerable difficulty in visualising the apparatus that you are trying to describe. Is there any chance of you putting a hand drawn sketch on the Web, please? In my experience, commercial tubing is not usually very accurate and very often it is not quite circular. Hard drawn seamless tube is best. If you just want a lot of mass, why not use solid bar? I am trying to figure out how you maintain the alignment with four pads... > I have built a commercial system, with a moving mass of about 10 Kg. (It > cost about $800,000) with 0.3 nanometer laser position feedback. I have > never thought of looking for seismic effects on this device, but I'll bet > that they are there. That particular device is used for metrology, and has > an overall position accuracy of less than 10 nanometers. I am very curious to know why you used an optical measurement system? Getting down below about 10 nm is hard work optically. What frequency range was this over? Resolving 0.1 nano metre is not difficult or expensive with a linear capacitative detector. However, when you get down to these dimensions, thermal expansion effects are dominant and you can only stabilise the centre of position of the detector. Even fused silica has an expansion coefficient of 0.2 ppm / C Deg > The noise from air bearings is low enough so that I have been able to > machine 10 Angstrom RMS surface finishes in aluminum on these bearings. Great. My experience with air bearings has not been quite so good. What precautions do you take with the air supply? What pressure, filters, flow restrictors and pressure regulators do you use / propose for this? Regards, Chris Chapman In a message dated 06/04/= 03, dyouden@......... writes:

Hi Dave,

      Thanks for the reply.

I guess complexity depends=20= upon personal viewpoint to some degree. What you have described seems comple= x to me. I have built systems similar to what you describe and the complexit= y springs from having to prevent rotation.
      ? It is two flat sheets= of glass with 4 pairs of small magnets and two strips of metal mounted hori= zontally on top of the top sheet --- it's not too complicated! I would expec= t it to be rather easier to prevent rotation than to do the linear positioni= ng.=20

My stack of tub= es originates from the challenge of making a relatively accurate prismatic s= hape without resorting to machine tools, which most of us don't have. Commer= cial tubing is pretty repeatable stuff, although not especially accurate.
      I have very considerabl= e difficulty in visualising the apparatus that you are trying to describe. I= s there any chance of you putting a hand drawn sketch on the Web, please? In= my experience, commercial tubing is not usually very accurate and very ofte= n it is not quite circular. Hard drawn seamless tube is best. If you just wa= nt a lot of mass, why not use solid bar? I am trying to figure out how you m= aintain the alignment with four pads...

I have built a=20= commercial system, with a moving mass of about 10 Kg. (It cost about $800,00= 0) with 0.3 nanometer laser position feedback. I have never thought of looki= ng for seismic effects on this device, but I'll bet that they are there. Tha= t particular device is used for metrology, and has an overall position accur= acy of less than 10 nanometers.
      I am very curious to kn= ow why you used an optical measurement system? Getting down below about 10 n= m is hard work optically. What frequency range was this over?
      Resolving 0.1 nano metre is not dif= ficult or expensive with a linear capacitative detector. However, when you g= et down to these dimensions, thermal expansion effects are dominant and you=20= can only stabilise the centre of position of the detector. Even fused silica= has an expansion coefficient of 0.2 ppm / C Deg     

The noise from=20= air bearings is low enough so that I have been able to machine 10 Angstrom R= MS surface finishes in aluminum on these bearings.
    Great. My experience with air bearings has not=20= been quite so good. What precautions do you take with the air supply? What p= ressure, filters, flow restrictors and pressure regulators do you use / prop= ose for this?=20

      Regards,

      Chris Chapman
Subject: Re: A Free Mass seismometer From: "David H. Youden" dyouden@......... Date: Tue, 08 Apr 2003 06:07:34 -0400 Hi Chris, Sorry to be slow responding to you, but there is work to be done. For information on high resolution stage interferometry go to: http://www.zygo.com/ Select semiconductor, stage position, zmi systems, and read all about it. The stuff I usually use is the ZMI 2000 which costs about $9000 per axis. All that for one more fuzzy digit. More later, gotta go. Dave... At 12:38 PM 4/6/03 -0400, you wrote: >In a message dated 06/04/03, dyouden@......... writes: > >Hi Dave, > > Thanks for the reply. > >>I guess complexity depends upon personal viewpoint to some degree. What >>you have described seems complex to me. I have built systems similar to >>what you describe and the complexity springs from having to prevent rotation. > > > ? It is two flat sheets of glass with 4 pairs of small magnets and > two strips of metal mounted horizontally on top of the top sheet --- it's > not too complicated! I would expect it to be rather easier to prevent > rotation than to do the linear positioning. __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: A Free Mass seismometer From: ChrisAtUpw@....... Date: Tue, 8 Apr 2003 07:56:27 EDT In a message dated 08/04/03, dyouden@......... writes: > For information on high resolution stage interferometry go to: > http://www.zygo.com/ > Select semiconductor, stage position, zmi systems, and read all about it. Hi Dave, There is an excellent introductory document which will probably tell most folks more than they ever wanted to know about optical distance measurement using the wavelength of light, exactly how it is done and what the problems are. There are a lot of diagrams. This Technical Paper is in the section ZMI systems. "High-resolution, High-speed, Low Data Age Uncertainty, Heterodyne Displacement Measuring Interferometer Electronics". (149 k) I can see why these systems are so expensive. The max range given in metres is very impressive. Fortunately, we only need to measure distances of maybe 1 mm for seismometers and less for feedback systems, so capacitative detectors can cope with the range and give an order of magnitude greater resolution. However, my comment that optical systems which depend on wavelength need complex = expensive systems to get below 1/2 wavelenght seems to be accurate enough. Thanks Dave. I found it very instructive. Regards, Chris Chapman In a message dated 08/04/03, dyouden@......... writes:
For information on high res= olution stage interferometry go to:  http://www.zygo.com/
Select semiconductor, stage position, zmi systems, and read all about it= ..


Hi Dave,

      There is an excellent introductory=20= document which will probably tell most folks more than they ever wanted to k= now about optical distance measurement using the wavelength of light, exactl= y how it is done and what the problems are. There are a lot of diagrams.
      This Technical Paper is in the sect= ion ZMI systems. "High-resolution, High-speed, Low Data Age= Uncertainty, Heterodyne Displacement Measuring Interferometer Electronics".= (149 k) =20
      I can see why these sys= tems are so expensive. The max range given in metres is very impressive. For= tunately, we only need to measure distances of maybe 1 mm for seismometers a= nd less for feedback systems, so capacitative detectors can cope with the ra= nge and give an order of magnitude greater resolution.=20
      However, my comment that optical sy= stems which depend on wavelength need complex =3D expensive systems to get b= elow 1/2 wavelenght seems to be accurate enough.
      Thanks Dave. I found it very instru= ctive.

      Regards,

      Chris Chapman Subject: Intrusion Sensors From: "Michael King" Mike@........................ Date: Tue, 8 Apr 2003 15:09:12 -0700 I am designing intrusion sensors to detect people entering the country = illegally in southern AZ. I am the technical director of the American = Border Patrol. Some of yo may have heard of us. I am looking for a = good circuit that uses very little power and has little noise but = amplifies alot. If anyone can help me it would be appreciated and you = would be helping our country guard it's borders. Michael S. King Technical Director American Border Patrol
I am designing intrusion sensors to = detect people=20 entering the country illegally in southern AZ. I am the technical = director=20 of the American Border Patrol.  Some of yo may have heard of = us.  I am=20 looking for a good circuit that uses very little power and has little = noise but=20 amplifies alot.  If anyone can help me it would be appreciated = and you=20 would be helping our country guard it's borders.
 
 
Michael S. King
Technical = Director
American=20 Border Patrol
Subject: Re: Intrusion Sensors From: Henry Bland henry@............... Date: Tue, 08 Apr 2003 16:47:52 -0600 Michael King wrote: > I am designing intrusion sensors to detect people entering the country > illegally in southern AZ. I am the technical director of the American > Border Patrol. Some of yo may have heard of us. I am looking for a > good circuit that uses very little power and has little noise but > amplifies alot. If anyone can help me it would be appreciated and you > would be helping our country guard it's borders. We use LT1800 chips (www.linear.com) for our low-power work Personally, I would stick to using dogs rather than electronics to detect intruders. They're generally better at discriminating between people noise and background noise. Cheers, -Henry Bland CREWES, University of Calgary __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Intrusion Sensors From: ChrisAtUpw@....... Date: Tue, 8 Apr 2003 21:01:10 EDT In a message dated 08/04/03, Mike@........................ writes: > I am designing intrusion sensors to detect people entering the country > illegally in southern AZ. I am the technical director of the American > Border Patrol. Hi there Michael, There are several low noise, low power opamps available. To be of more help we need to know what sensors and impedance you are using and what power supplies are available. You may also have to consider filters and communication systems. There are usually several used Military systems on Ebay, geophones + radios. Regards, Chris Chapman In a message dated 08/04/= 03, Mike@........................ writes:

I am designing intrusion se= nsors to detect people entering the country illegally in southern AZ. I am t= he technical director of the American Border Patrol.  


Hi there Michael,

      There are several low noise, low po= wer opamps available. To be of more help we need to know what sensors and im= pedance you are using and what power supplies are available. You may also ha= ve to consider filters and communication systems. There are usually several=20= used Military systems on Ebay, geophones + radios.

      Regards,=20

      Chris Chapman=20
Subject: Re: Intrusion Sensors From: "Mauro Mariotti" mariotti@......... Date: Wed, 9 Apr 2003 08:56:11 +0200 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. Just an idea... regards Mauro ----- Original Message -----=20 From: Michael King=20 To: PSN-L@................. Sent: Wednesday, April 09, 2003 12:09 AM Subject: Intrusion Sensors I am designing intrusion sensors to detect people entering the country = illegally in southern AZ. I am the technical director of the American = Border Patrol. Some of yo may have heard of us. I am looking for a = good circuit that uses very little power and has little noise but = amplifies alot. If anyone can help me it would be appreciated and you = would be helping our country guard it's borders. Michael S. King Technical Director American Border Patrol
Hi Mr. King,
 
I think that the major problem is what = sensor to=20 use instead of
what amplifier use.
Geophones have a limited detection = range and not=20 detect a person
that eventually walk = softly.
It could detect a running animal = instead or an=20 animal trying to bury
something near the sensor.
Probably a better sensor is a = pressurized rubber=20 pipe buried along the border
that could be long 10 - 20 meters or=20 more.
Then you can measure the pressure = variation at one=20 extremity when
someone walk over it.
 
Just an idea...
 
regards
Mauro
 
----- Original Message -----
From:=20 Michael King
Sent: Wednesday, April 09, 2003 = 12:09=20 AM
Subject: Intrusion = Sensors

I am designing intrusion sensors to = detect people=20 entering the country illegally in southern AZ. I am the technical = director of the American Border Patrol.  Some of yo may have = heard of=20 us.  I am looking for a good circuit that uses very little power = and has=20 little noise but amplifies alot.  If anyone can help me it = would be=20 appreciated and you would be helping our country guard it's=20 borders.
 
 
Michael S. King
Technical = Director
American=20 Border Patrol
Subject: Re: Intrusion Sensors From: "Mauro Mariotti" mariotti@......... Date: Wed, 9 Apr 2003 08:56:11 +0200 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. Just an idea... regards Mauro ----- Original Message -----=20 From: Michael King=20 To: PSN-L@................. Sent: Wednesday, April 09, 2003 12:09 AM Subject: Intrusion Sensors I am designing intrusion sensors to detect people entering the country = illegally in southern AZ. I am the technical director of the American = Border Patrol. Some of yo may have heard of us. I am looking for a = good circuit that uses very little power and has little noise but = amplifies alot. If anyone can help me it would be appreciated and you = would be helping our country guard it's borders. Michael S. King Technical Director American Border Patrol
Hi Mr. King,
 
I think that the major problem is what = sensor to=20 use instead of
what amplifier use.
Geophones have a limited detection = range and not=20 detect a person
that eventually walk = softly.
It could detect a running animal = instead or an=20 animal trying to bury
something near the sensor.
Probably a better sensor is a = pressurized rubber=20 pipe buried along the border
that could be long 10 - 20 meters or=20 more.
Then you can measure the pressure = variation at one=20 extremity when
someone walk over it.
 
Just an idea...
 
regards
Mauro
 
----- Original Message -----
From:=20 Michael King
Sent: Wednesday, April 09, 2003 = 12:09=20 AM
Subject: Intrusion = Sensors

I am designing intrusion sensors to = detect people=20 entering the country illegally in southern AZ. I am the technical = director of the American Border Patrol.  Some of yo may have = heard of=20 us.  I am looking for a good circuit that uses very little power = and has=20 little noise but amplifies alot.  If anyone can help me it = would be=20 appreciated and you would be helping our country guard it's=20 borders.
 
 
Michael S. King
Technical = Director
American=20 Border Patrol
Subject: Re: Intrusion Sensors From: John Hernlund hernlund@............ Date: Wed, 9 Apr 2003 00:35:21 -0700 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. 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 On Tuesday, April 8, 2003, at 11:56 PM, Mauro Mariotti wrote: ArialHi Mr. King, ArialI think that the major problem is what sensor to use instead of Arialwhat amplifier use. ArialGeophones have a limited detection range and not detect a person Arialthat eventually walk softly. ArialIt could detect a running animal instead or an animal trying to bury Arialsomething near the sensor. ArialProbably a better sensor is a pressurized rubber pipe buried along the border Arialthat could be long 10 - 20 meters or more. ArialThen you can measure the pressure variation at one extremity when Arialsomeone 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. 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 Subject: Re: Intrusion Sensors From: "Mauro Mariotti" mariotti@......... Date: Wed, 9 Apr 2003 10:35:55 +0200 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
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
Subject: Tiltmeter question From: "David H. Youden" dyouden@......... Date: Wed, 09 Apr 2003 06:11:50 -0400 All, Has anyone out there ever built a tiltmeter based on a simple balance beam? What can you tell me about it? Dave... __________________________________________________________ Public Seismic Network Mailing List (PSN-L) Subject: Re: Intrusion Sensors From: Thomas W Leiper twleiper@........ Date: Wed, 9 Apr 2003 11:01:39 -0400 I would concentrate on prevention, not detection. An electrified fence with, say a half million volts would probably work. Also, we could take a lesson from Saddam and have trenches full of burning oil... Seriously, though, I think you have a big challenge. Seismic detection of people walking at any significant distance would be next to impossible because, even though you might achieve some kind of amazing sensitivity, you would never be able to decode the data and the false positive rate would be excessive. Hell, just the 6 second noise and background would cover over everything but King Kong. I think some kind of visual system would be able to monitor huge areas at little expense, especially compared to seismic sensors. A digital camera with an expansive and essentially static field of view could definitely be used along with a program to analyze the images for changes. A random change of pixels, for instance would not be indicative, however a chain of adjacent pixels that have changed would be. And, of course IR detection at night is a no-brainer. How about using R/C model planes as drones with little video cameras? I like that approach because they are noisy, which lends a preventive element. You can always fly the plane right into there head if they don't turn around. You might even get some of them to surrender! On Wed, 9 Apr 2003 10:35:55 +0200 "Mauro Mariotti" writes: 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 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 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 ----- From: John Hernlund 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. 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
I would concentrate on prevention, not detection. An electrified
fence with, say a half million volts would probably work. Also,
we could take a lesson from Saddam and have trenches full of
burning oil...
 
Seriously, though, I think you have a big challenge. Seismic
detection of people walking at any significant distance would
be next to impossible because, even though you might achieve
some kind of amazing sensitivity, you would never be able to
decode the data and the false positive rate would be excessive.
Hell, just the 6 second noise and background would cover
over everything but King Kong.
 
I think some kind of visual system would be able to monitor
huge areas at little expense, especially compared to seismic
sensors. A digital camera with an expansive and essentially
static field of view could definitely be used along with a
program to analyze the images for changes. A random change
of pixels, for instance would not be indicative, however a
chain of adjacent pixels that have changed would be. And,
of course IR detection at night is a no-brainer.
 
How about using R/C model planes as drones with little
video cameras? I like that approach because they are noisy,
which lends a preventive element. You can always fly the
plane right into there head if they don't turn around.
 
You might even get some of them to surrender!
 
 
On Wed, 9 Apr 2003 10:35:55 +0200 "Mauro Mariotti" <mariotti@.........> writes:
John,
 
agreed a lot of pipe would be=20 needed.
But also a lot of seismic sensors if = they would=20 be 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=20 not more and not at all if
he is walking softly.
The cost of a 50 meters of rubber pipe = is small=20 if 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=20 sort 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
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=20 think that the major problem is what sensor to use instead of
what=20 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<= ?/smaller>
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=20 who once did seismic sensors in the first Iraq war. They have (of = course!)=20 an 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=20 fire-finding radar, or something like that) pin point the location of = an=20 enemy's artillery and then be able to fire back at the correct position= .. He=20 also said that it could pick up large vehicle convoys or even people on= foot=20 when they were very numerous and fairly close.

What works in = the=20 Army tends not to be the case along the AZ border, which is run by = coyotes=20 hauling mostly smaller groups of people on foot...some times abandoning= =20 large numbers of them in the middle of the desert leading to hundreds = of=20 deaths from heat exhaustion, etc.. On a number of occasions I've run = across=20 a taxi looking for fares in the middle of the desert! In a few border = towns=20 there have been incidents of thousands of people lining up along the = border,=20 and then crossing all at once...thus overwhelming the border patrol...= but=20 not much is able to stop this from happening. The worst is the drug = runners=20 who are almost always armed and quite willing to shoot first and see = who it=20 is later...this may account for the low morale in the border patrol in = some=20 areas, since quite a few of them have been killed. No doubt about it, = the=20 lax border enforcement in the past decade in Arizona has caused this to= be=20 the main conduit for illegal cross-border activity in the US. It has = brought=20 the Mexican mafia into Phoenix, where they took control of much of the= =20 illegal activity there. They are a bold and brutal organization, and = even=20 wear clothing, drive trucks, etc. in a uniform way that announces who = they=20 are; i.e. their presence and lack of fear. A friend of mine, a Phoenix = cop,=20 lost his partner when a group of them telephoned the police and laid a= =20 trap...apparently just for "fun."

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

Cheers!
John
 
Subject: Seismic intrusion detectors part 2 From: "Michael King" Mike@........................ Date: Wed, 9 Apr 2003 10:02:47 -0700 Here is the overall design. The sensor consists of (2) geophones. They are places aprox. 30-40 feet = apart on a known trail that illegals use.=20 The prototypes we are using have (2) LT1677 opamp circuits that amplify = the geophone outputs and feed the signal into a basic stamp 1. The = level of signal isn't converted to digital, the signal when large enough = (about 1.67 volts) will drive the input pin high and thus we have a = logic switch. In order to limit false hits the software in the basic stamp listens for = a hit on a geophone. When there is a hit it basically says if the = second geopghone is hit within the next 2 seconds cancel the entire hit = becuase it is most likely rain or some other seismic disturbance. If = the gephone is hit after that to seconds the it is a real hit and send a = signal back to us through our repeater. The data coming to us tells us = what "port" hit first and what sensor it is. By knowing what port was = hit first we can tell what direction the contact is going. =20 During initial powerup we callibrate the instrument by "walking the = line" or walking by both geophones. By doing this and counting the = number of footfalls on an average man we can the have a rudimentary = counting of the number of people walking by. By dividing the number of = detected footfall by the number of detected footfalls in the calibration = we have the number of intruders. It all works but the noisy circuit is = killing me. This system works but our circuit is noisy and when I make the software = just send hits on either geophone as they come in, sometimes, at random, = one or both of the "ports" will show hits for minutes on end. If I = touch the circuit board with my finger i can kill the noise until some = kind of seismic activity start the noise again. Michael S. King Technical Director American Border Patrol
Here is the overall = design.
 
The sensor consists of (2) = geophones.  They=20 are places aprox. 30-40 feet apart on a known trail that illegals=20 use. 
 
The prototypes we are using have (2) = LT1677 opamp=20 circuits that amplify the geophone outputs and feed the signal into a = basic=20 stamp 1.  The level of signal isn't converted to digital, the = signal when=20 large enough (about 1.67 volts) will drive the input pin high and t