One device indicated here in this group goes down to 0.0001G
and cost like 1900 USD probably with taxes.
which is cheaper than a HS-10 brand new.

But I think you may want 50 feet of cable between
your computer and the device located underground
and yet I have not seen a device allowing
50 feet of cable.

USB is not what you want.

You want ETHERNET for like 50 feet of distance.

Possibly with power sent to the device underground.

I have yet to see any device built with ethernet communications in mind.


----- Original Message ----- 
From: 
To: 
Sent: Thursday, November 12, 2009 12:50 AM
Subject: Re: WinQuake Times


> In a message dated 12/11/2009, mark.robinson@............... writes:
> 
> ChrisAtUpw@....... wrote:
>> In a message dated 11/11/2000,  gmvoeth@........... writes:
>>     If the MEMS were 1000  times more sensitive
>>     then that means 2G+/- becomes  0.002G+/-
> 
>> Hi Geoff,
>>     The good news  is that HP don't make them.
>>     See  http://www.colibrys.com/e/page/140/
> 
> Are my calculations indicating a  noise level of 1 milli-gravity at a 
> period of 
> 10,000,000 seconds correct  ?
> 
> Hi Mark,
> 
>    Don't think so.
> 
>    The normal  MEMS accelerometer devices have a  dynamic range of about 
> 93 dB Max, often less. The range has been  extended in the newer devices to 
> over 120 dB. They still remain basic  strong motion accelerometers from +/- 3 
> g downwards. My interpretation the the  company has at last learned to good 
> senors
> 
> Dare I  wonder how much these things cost ?
>    I suggest that you simply ask.
> 
>    Regards,
> 
>    Chrid Chapman
>
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