Hi Ted,=20 I built a vertical based on a Honeywell Hall Effect sensor SS495A. It = worked quite well at the time. EPE online magazine had an article in = April 2004 for a vertical using the SS495A http://www.epemag.wimborne.co.uk/projects2004.html Dale ----- Original Message -----=20 From: tchannel1@............... To: psn-l@................. Sent: Tuesday, March 18, 2008 10:43 AM Subject: Re: Scientific American 1884 Part 2 Hi Chris, Is this the type of Hall Effect Magnetic field detector = chip http://www.allegromicro.com/en/Products/Design/an/an27701.pdf I see one chip can determined direction. X and Y? If this is so, = is there a way to apply that directional information to trip a relay or = otherwise light a series of LED's They look inexpensive, $2, so if not one, we could use several, (8) to = form a compass. Thanks, Ted ----- Original Message -----=20 From: ChrisAtUpw@.......... To: psn-l@................. Sent: Monday, March 17, 2008 4:37 PM Subject: Re: Scientific American 1884 Part 2 In a message dated 2008/03/17, tchannel1@............ writes: But how would one record the pendulum direction of movement?=20 Hi Ted, If you want tthe system to work for small quakes, use either = a vertical magnet and two pairs of Hall Effect Magnetic field detector = chips or use a disk on the end of the penduum, a lamp and four = photocells. Either of these could give you the X and Y sensitivities. Or make it to the design and accept that it is not a very = sensitive device. Maybe put a flat on the top of the pendulum and set a = ball bearing on the flat? This might give appreciable sensitivity? Regards, =20 Chris Chapman=20 -------------------------------------------------------------------------= ----- Internal Virus Database is out-of-date. Checked by AVG.=20 Version: 7.5.519 / Virus Database: 269.21.7 - Release Date: 8/03/2008 = 12:00 AMHi Ted,I built a vertical based on a Honeywell = Hall Effect=20 sensor SS495A. It worked quite well at the time. EPE online magazine had = an=20 article in April 2004 for a vertical using the SS495ADale----- Original Message -----From:=20 tchannel1@............ =Sent: Tuesday, March 18, 2008 = 10:43=20 AMSubject: Re: Scientific = American 1884=20 Part 2Hi Chris, Is this the type of = Hall Effect=20 Magnetic field detector chip ht= tp://www.allegromicro.com/en/Products/Design/an/an27701.pdfI see one chip can determined = direction. X=20 and Y? If this is so, is there a way to = apply=20 that directional information to trip a relay or otherwise light a = series of=20 LED'sThey look inexpensive, $2, so if not = one, we=20 could use several, (8) to form a compass.Thanks, Ted----- Original Message -----From:=20 ChrisAtUpw@.......Sent: Monday, March 17, 2008 = 4:37=20 PMSubject: Re: Scientific = American 1884=20 Part 2In a=20 message dated 2008/03/17, tchannel1@............=20 writes:
But how would one record the pendulum direction of = movement?=20
Hi=20 Ted,
If you want tthe = system to=20 work for small quakes, use either a vertical magnet and two pairs of = Hall=20 Effect Magnetic field detector chips or use a disk on the end of the = penduum, a lamp and four photocells. Either of these could = give you=20 the X and Y sensitivities.
= Or make=20 it to the design and accept that it is not a very sensitive device. = Maybe=20 put a flat on the top of the pendulum and set a ball bearing on the = flat?=20 This might give appreciable=20 sensitivity?
=20 Regards,
=20
Chris Chapman=20
Internal Virus Database is out-of-date.
Checked by AVG. =
Version:=20 7.5.519 / Virus Database: 269.21.7 - Release Date: 8/03/2008 12:00=20 AM
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