barry lotz wrote: > Ruediger > It may work as a strong motion sensor. I agree with Ted, usually you want > the natural period of the sensor to be longer than the lowest period you want > to record. Also since the output would be a function of the # of wire coils > turns you may have a very low output signal . Speakers usually have few turns. But is it possible, that the strong magnet more than compensats this disadvantage? A simple test with a big loudspeaker, a simple amplifier with a 741 and amp.factor 100 gives a strong signal, when I just make a bit wind with my hand against the membran. > > What you describe maybe the begining of a force balance sensor but you would > need a displacement sensor included which would complicate matters. I have read the article about the force-balance-seismometer, but due to my oor english I haven`t quite understood the difference between the forcebalance and the lehman-sensor. Why do you need a displacement sensor? > Do you have > access to magnet wire and simple rectangular magnets? You could use an electric > drill and wind your own coil of 1000+ turns on say a old spool like an empty > solder spool. Is it better for a high voltage to have a short coil with much layers or does a long coil with the same number of wires produeces the same effect? > You could then put a rectangular magnet on both sides of the > coil. As Ted says you probable will have more interesting events if you do not > attach the groung to the end of the boom except as I have described above. I > hope this helps a little. Most of us look around to find possible sensor > parts from devices use for other things, for example computer harddrive driver > as sensor/coil pairs. I still have some old harddisks, thanks for that hint. > > Barry > > ted@.......... wrote: > Thanks Ruediger Wisskirchen (rwisskirchen@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>