On 12/31/2012 6:40 PM, chrisatupw@....... wrote:
> From: Geoff 
> To: psnlist 
> Sent: Sun, 30 Dec 2012 23:14
> Subject: Re: Instrumentation Question
>
> There must be some kind of strain gauge where you simply hang a weight 
> like a pendulum
> and any swing however slight would create a signal.
>
> ****Strain gauges give quite a low sensitivity.
>
> Then the signal would be omnidirectional which is what I am looking for.
>
> A single plane oriented sensor which produces an omnidirectional signal.
>
> A hovering mass like the globes you can buy
> suspended within a magnetic field
>
> ****Don't know- who makes them ?
>
> A gyroscope of light where you measure phase differences between input 
> and output
> A laser beam traveling through a fiber optic coil.
>
> ****These may be a bit temperature sensitive and require fairly expensive
> optical components.
>
> A foam pad which changes resistance with compression
> so you just put a mass like a gallon of water on it
> to measure vertical forces
>
> ???
>
> Isn't there something novel and cheap and easy to try ???
>
> ****Yes. 44mm OD Piezo Sounder Disks and a weight. I use about 1 oz.
>
>     Regards,
>
>     Chris Chapman

LOL, yes but looking at your design it takes a mechanical
engineer to put it together,

I would need a kit ready to build or one already prebuilt.

But with the economy like it is today, My fun days might be over.

I often thought an inverted pendulum with a couple of
pizo thingys flexing at the bottom in like a bridge affair
might do the job.

Even tho I cant play much anymore I will watch
as much as I can whats going on.

I cant wait to see what kind of seismometer
they eventually send to planets in the
solar system with gravity less than our own.

I think the one they sent to the moon was
quite conventional with a type of pendulum.
But can you imagine how much it cost
to build and get it there.

The moons seismicity is interesting to read about.
They even have seismic signatures of meteor strikes
on the moon.

Happy New Year 2013,
geoff

  
    
  
  
    
On 12/31/2012 6:40 PM,
      chrisatupw@....... wrote:

    
    
From: Geoff
        <gmvoeth@...........>

        
        
      

            To: psnlist <psnlist@..............>

            Sent: Sun, 30 Dec 2012 23:14

            Subject: Re: Instrumentation Question

          
        


              There must be some kind of strain gauge where you simply
              hang a weight like a pendulum

              and any swing however slight would create a signal.

              

              ****Strain gauges give quite a low sensitivity.

              

              Then the signal would be omnidirectional which is what I
              am looking for.

              

              A single plane oriented sensor which produces an
              omnidirectional signal.

              

              A hovering mass like the globes you can buy

              suspended within a magnetic field 

              

              ****Don't know - who makes them ?

              

              A gyroscope of light where you measure phase differences
              between input and output

              A laser beam traveling through a fiber optic coil.

              

              ****These may be a bit
                  temperature sensitive and
                  require fairly expensive
                      

                      optical components.

              

              A foam pad which changes resistance with compression

              so you just put a mass like a gallon of water on it

              to measure vertical forces 

              

              ???

              

              Isn't there something novel and cheap and easy to try ???

              

              ****Yes. 44mm
                    OD Piezo Sounder Disks and a weight.
                      I use about 1 oz. 

                      

                          Regards, 

                          

                              Chris Chapman

                        
        
        
      
    
    

    LOL, yes but looking at your design it takes a mechanical

    engineer to put it together,

    

    I would need a kit ready to build or one already prebuilt.

    

    But with the economy like it is today, My fun days might be over.

    

    I often thought an inverted pendulum with a couple of

    pizo thingys flexing at the bottom in like a bridge affair

    might do the job.

    

    Even tho I cant play much anymore I will watch

    as much as I can whats going on.

    

    I cant wait to see what kind of seismometer

    they eventually send to planets in the

    solar system with gravity less than our own.

    

    I think the one they sent to the moon was

    quite conventional with a type of pendulum.

    But can you imagine how much it cost

    to build and get it there.

    

    The moons seismicity is interesting to read about.

    They even have seismic signatures of meteor strikes

    on the moon.

    

    Happy New Year 2013,

    geoff