Hi Ted,

Nothing new, but; music (piano) wire is very hard to beat for its high
tensile strength, durability, low cost and a good variation of diameter size
availability at a variety of hardware and hobby shops.   Think you'll
eventually gravitate over to this material, as the material you've tried
will
stretch sag and change the period and position of the boom/mass if theirs
much of any weight involved in mass/boom you have or will try in the future.


Was wondering if you're contemplating making your "T" connection or
boom/wire connection to where it uses up the majority length of the wire?
If you get to this arrangement I would think if would allow more mass
weight, and limit too much wire play; while still using the wire torsion
aspect.
Am speculating...but say if your wire is 14" length, and your "T" length is
~ 10"; you could still see a lot of reasonable good response.   Clamping
down
on the wire to where the "T" doesn't gravity weight slide down over time
might be a real anticipated potential problem.

I'd think the frame for such, would have to be mechanically superior to
support the wire tension necessary; i.e., big bulky high strength.  One may
have to even use stuff like iron plumbing pipes with its lousy temperature
variations to get the high strength.  Aluminum would be temperature"nicer",
but
obtaining really strong thick aluminum might only be available via a metals
scrap yard; and then, you'd need tools to work it down to the desired
size/s.
Overcoming this frame strength necessity is a major obstacle for a long
lasting torsion wire seismometer especially for a higher mass weight
variety.

Musings....

Take care, Meredith




On Tue, Oct 7, 2008 at 7:39 AM,  wrote:

>  Hi Folks,  I just recorded the first event using my Torsion wire/spring
> sensor.   The sensor was made using some bits and pieces from other units.
> The construction was not carefully designed or executed, as I just wanted to
> see if the concept would work.   I will post three examples on PSN, Ch 1=a
> simple pendulum with a 2 second period,  Ch 2=The New Torsion Spring with a
> 5second period, Ch 3= a Lehman at 20 seconds.
> All three sensor recorded the 5.8M ARCTIC OCEAN today.
>
> I have another Torsion Spring Mock-up made of wood on my bench, not to
> used, but to test for general dimensions and period.   Happy to send picts
> and discuss design with anyone who is interested in helping me build a
> proper unit.   The mock up is only 18"? tall, has a torsion spring of about
> 14" and a boom of 12".  The frame looks like a Lehman, and the wire is near
> the vertical support.   Under these conditions I could get a period of 25
> seconds, but unstable.  It now is adjusted to 15 seconds and seems stable.
> A longer or shorter period should be possible.
>
> The Wire is not spring wire, although it has some spring to it.  It is
> .016" ss fishing lure.   Thanks to J.P. for sending me the wire.   For my
> experiments I have used, a bandsaw blade, brass music wire, and SS fishing
> wire.
>
> Anyhow the idea seems to work and and very easy to adjust.  I am not sure
> what sensor period I should target.   Deciding that will dictate many of the
> other dimensions and overall size.
>
> Cheers, Ted
>
Hi Ted,

Nothing new, but; music (piano) wire is very hard to beat for its high tensile strength, durability, low cost and a good variation of diameter size
availability at a variety of hardware and hobby shops.   Think you'll eventually gravitate over to this material, as the material you've tried will

stretch sag and change the period and position of the boom/mass if theirs much of any weight involved in mass/boom you have or will try in the future. 

Was wondering if you're contemplating making your "T" connection or boom/wire connection to where it uses up the majority length of the wire?

If you get to this arrangement I would think if would allow more mass weight, and limit too much wire play; while still using the wire torsion aspect.
Am speculating...but say if your wire is 14" length, and your "T" length is ~ 10"; you could still see a lot of reasonable good response.   Clamping down

on the wire to where the "T" doesn't gravity weight slide down over time might be a real anticipated potential problem.

I'd think the frame for such, would have to be mechanically superior to support the wire tension necessary; i.e., big bulky high strength.  One may

have to even use stuff like iron plumbing pipes with its lousy temperature variations to get the high strength.  Aluminum would be temperature"nicer", but
obtaining really strong thick aluminum might only be available via a metals scrap yard; and then, you'd need tools to work it down to the desired size/s.

Overcoming this frame strength necessity is a major obstacle for a long lasting torsion wire seismometer especially for a higher mass weight variety.  

Musings....

Take care, Meredith
      




On Tue, Oct 7, 2008 at 7:39 AM,  <tchannel1@............> wrote:








Hi Folks,  I just recorded the first event 
using my Torsion wire/spring sensor.   The sensor was made 
using some bits and pieces from other units.  The construction was not 
carefully designed or executed, as I just wanted to see if the concept would 
work.   I will post three examples on PSN, Ch 1=a simple pendulum with 
a 2 second period,  Ch 2=The New Torsion Spring with a 5second period, Ch 
3= a Lehman at 20 seconds.
All three sensor recorded the 5.8M ARCTIC OCEAN 
today.
 
I have another Torsion Spring Mock-up made of wood 
on my bench, not to used, but to test for general dimensions and 
period.   Happy to send picts and discuss design with anyone who is 
interested in helping me build a proper unit.   The mock up is only 
18"? tall, has a torsion spring of about 14" and a boom of 12".  The frame 
looks like a Lehman, and the wire is near the vertical support.   
Under these conditions I could get a period of 25 seconds, but unstable.  
It now is adjusted to 15 seconds and seems stable.  A longer or shorter 
period should be possible.
 
The Wire is not spring wire, although it has some 
spring to it.  It is .016" ss fishing lure.   Thanks to J.P. for 
sending me the wire.   For my experiments I have used, a bandsaw 
blade, brass music wire, and SS fishing wire.
 
Anyhow the idea seems to work and and very easy to 
adjust.  I am not sure what sensor period I should target.   
Deciding that will dictate many of the other dimensions and overall 
size.
 
Cheers, Ted