Hi Folks,  Merry Christmas and a Happy New Year to all.   I am building =
a vertical spring sensor, using 1" and 1/2" copper water pipe and all =
the common tees, elbows etc, avail at any Home Building Supply store.   =
I have seen sensor made from wood, aluminum so I thought I would use =
copper pipe simply because I had some left over pieces.  Interesting to =
me is that it seems to be working just fine.  The unit is about half =
done, and here are some things I like about it so far.   The shape is =
basically similar to a AS1, it has a "T" for the base, an  "Arm", a =
vertical column which forms a "L" to the base, a  "zero length" 6" =
spring, and lots of tees and fittings.
1.  If you have some copper tubing, and fittings, the cost is not too =
bad, because the sensor is so small, about 20" long 9" wide and 11" =
tall.
     I chose the dims to fit inside a fish aquarium, which I will invert =
and use as a cover for the sensor.  This too was from the salvage pile.
2.  I soldered the fitting together, using just a little solder to hold =
it without big, ugly, globs of solder around the joints, as it doesn't  =
need to hold water.
     It will look better when I polish the copper up.
3.  Some joints I wanted  to rotate.  Not too loose, but loose enough to =
rotate with your hands.  On these joints, which were too loose to hold =
their position when connected, but not soldered,  I used a punch and =
created a dimple on the outside of the tube.  When I inserted the tube =
into a tee or elbow, it became very tight and would hold it position, =
until you twisted it to a new location.
4.   At this point, the frame is done, the three adjusting leveling feet =
and the spring.   I still need to build the damper, the coil/magnet and =
mass, but so far so good.

Q.   My question at this point is: What is the target for the period?   =
The sensor is adjustable, the spring can be tightened, the hinge and arm =
can be lower, etc.  Any adjust I make, changes the period, if I tweak it =
I can get 4 seconds, but the stable position on the arm is small.  If I =
change the period to 3 seconds, I seem to get a larger area of stability =
in the arc of the arm.   By unstable I mean, If I move the horizontal =
spring loaded arm up or down a little it will return to center, however, =
 If I move it too far up it will fall toward the spring.    Should I =
target the longest period I can get, even thought the arm is touchy and =
could fall up or down?  Or should I target less the maximum in order to =
get a more stable arm?

I can send pictures, of the frame, if anyone is interested...... I am =
not sure this will be the best design, but it may provide food for =
thought.  Seeing something different can often generate new ideas.







Hi Folks,  Merry Christmas and a =
Happy New=20
Year to all.   I am building a vertical spring sensor, using =
1" and=20
1/2" copper water pipe and all the common tees, elbows etc, avail at any =
Home=20
Building Supply store.   I have seen sensor made from wood, =
aluminum=20
so I thought I would use copper pipe simply because I had some left over =

pieces.  Interesting to me is that it seems to be working just =
fine. =20
The unit is about half done, and here are some things I like about it so =

far.   The shape is basically similar to a AS1, it has =
a "T"=20
for the base, an  "Arm", a vertical column which forms a "L" to the =
base,=20
a  "zero length" 6" spring, and lots of tees and =
fittings.
1.  If you have some copper =
tubing, and=20
fittings, the cost is not too bad, because the sensor is so small, about =
20"=20
long 9" wide and 11" tall.
     I chose the =
dims to fit=20
inside a fish aquarium, which I will invert and use as a cover for the=20
sensor.  This too was from the salvage pile.
2.  I soldered the fitting =
together, using=20
just a little solder to hold it without big, ugly, globs of solder =
around the=20
joints, as it doesn't  need to hold water.
     It will look =
better when I=20
polish the copper up.
3.  Some joints I wanted =
 to rotate.  Not too loose, but loose enough =
to rotate=20
with your hands.  On these joints, which were too loose to hold =
their=20
position when connected, but not soldered,  I used a punch and =
created a=20
dimple on the outside of the tube.  When I inserted the tube into a =
tee or=20
elbow, it became very tight and would hold it position, until you =
twisted it to=20
a new location.
4.   At this point, the frame =
is done,=20
the three adjusting leveling feet and the spring.   I still =
need to=20
build the damper, the coil/magnet and mass, but so far so =
good.
 
Q.   My question at this =
point is: What=20
is the target for the period?   The sensor is adjustable, the =
spring=20
can be tightened, the hinge and arm can be lower, etc.  Any adjust =
I make,=20
changes the period, if I tweak it I can get 4 seconds, but the stable =
position=20
on the arm is small.  If I change the period to 3 seconds, I seem =
to get a=20
larger area of stability in the arc of the arm.   By unstable =
I mean,=20
If I move the horizontal spring loaded arm up or down a little it will =
return to=20
center, however,  If I move it too far up it will fall toward the=20
spring.    Should I target the longest period I can get, =
even=20
thought the arm is touchy and could fall up or down?  Or should I =
target=20
less the maximum in order to get a more stable arm?
 
I can send pictures, of the =
frame, if anyone=20
is interested...... I am not sure this will be the best design, but it =
may=20
provide food for thought.  Seeing something different can =
often=20
generate new ideas.
Thanks, Ted