Sounds very interesting to me. Please include photos and description ! = Thanh you, hans stauffer ----- Original Message -----=20 From: Tangazazen@.......... To: psn-l@................. Sent: Sunday, February 21, 2010 12:59 PM Subject: Orthogonal seismometer=20 Hi All, It seems to have gone rather quiet on the subject of seismometers = lately.=20 I was wonder if there is any interest in a orthogonal pendulum = broadband version which has been in operation for 3 years without = problems. It consists of a short pendulum with a natural period of 1 second and = supported by 4 leaf springs such that it has two degrees of freedom. The = electronics gives the pendulum a period of 50 seconds and uses an LED = attached to projects a spot of light onto a quadrant photo detector thus = resolving an X and Y components. Orthogonal electromagnetic transducers hold the pendulum in a fixed = position as in the broadband configuration. Examination of the P wave on = an x-y plot gives a line of travel of the disturbance. If there is any interest I do have some photographs and a rough write = up. I am not a computer publishing expert,so rough is the operative = word.Sounds very interesting to me. Please include photos and = description !=20 Thanh you, hans stauffer----- Original Message -----From:=20 Tangazazen@.......Sent: Sunday, February 21, 2010 = 12:59=20 PMSubject: Orthogonal seismometer =Hi All,It seems to have gone rather quiet on the = subject of=20 seismometers lately.I was wonder if there is any interest in a orthogonal = pendulum=20 broadband version which has been in operation for 3 years = without=20 problems.It consists of a short pendulum with a natural period of 1 = second=20 and supported by 4 leaf springs such that it has two degrees of = freedom. The=20 electronics gives the pendulum a period of 50 seconds and uses an LED = attached=20 to projects a spot of light onto a quadrant photo detector thus = resolving an X=20 and Y components.Orthogonal electromagnetic transducers hold the pendulum in a = fixed=20 position as in the broadband configuration. Examination of the P wave = on an=20 x-y plot gives a line of travel of the disturbance.If there is any interest I do have some photographs and a rough = write=20 up. I am not a computer publishing expert,so rough is the = operative=20 word.Martin Page