Hi all,

Am getting to the (shall we say a unqualified) opinion that with a choice of
round or square/rectangular coils
with a magnet, that it seems like the round coil approach is the more
efficient route to take.  It just simply
uses all the coil and not just a couple selected sides mainly.  Theres
obviously no heavy
problem to making a round coil; versus the more construction work with a
square or rectangular coil.

The route you take with the round coil size/shape with the magnet/s can be
quite different than most now use.

Having multi or multiple round (or ring) magnets stacked attracting, with
the coil on the outside centered
seems to be a sensitive and quick approach.   One magnet can work, but with
2 or more, it will increase
the sensitivity, and, the coil will be normally centered down the length of
the magnet stack.  The magnets
are still mounted on a metal plate.  It still works normally; i.e., movement
in one direction will still be + or -
throughout its continued movement in that direction; and vice versa + or -
signal for the other direction.

For home brew seismometers with a heavy mechanical boom/coil drift problem;
this approach would seem
to be the best ideal design answer.

Although I've not actually done it, one could also put a iron can around and
slightly away from
such a coil/magnet assembly, and slightly increase the sensitivity, while
also providing a measure
of limiting some magnetic or electro magnetic induction "noise" pickup and
air or thermal influence also.

Tight and limited movement magnet coil assemblys are interesting to be sure;
but what the heck; your
amplifier gain controls should easily take up any slack.

Take care, Meredith Lamb
Hi all,

Am getting to the (shall we say a unqualified) opinion that with a choice of round or square/rectangular coils
with a magnet, that it seems like the round coil approach is the more efficient route to take.  It just simply

uses all the coil and not just a couple selected sides mainly.  Theres obviously no heavy
problem to making a round coil; versus the more construction work with a square or rectangular coil.  

 The route you take with the round coil size/shape with the magnet/s can be quite different than most now use.


Having multi or multiple round (or ring) magnets stacked attracting, with the coil on the outside centered
seems to be a sensitive and quick approach.   One magnet can work, but with 2 or more, it will increase

the sensitivity, and, the coil will be normally centered down the length of the magnet stack.  The magnets
are still mounted on a metal plate.  It still works normally; i.e., movement in one direction will still be + or - 

throughout its continued movement in that direction; and vice versa + or - signal for the other direction.

For home brew seismometers with a heavy mechanical boom/coil drift problem; this approach would seem
to be the best ideal design answer.


Although I've not actually done it, one could also put a iron can around and slightly away from
such a coil/magnet assembly, and slightly increase the sensitivity, while also providing a measure
of limiting some magnetic or electro magnetic induction "noise" pickup and air or thermal influence also.


Tight and limited movement magnet coil assemblys are interesting to be sure; but what the heck; your
amplifier gain controls should easily take up any slack. 

Take care, Meredith Lamb