Hi
Thanks for your comments - I am finding out that Vibration sensing is
pretty specialised - seem to be mainly designed for rotating machines
and various vehicle applications where the sensor produces an RMS output
over time.
I will need to get much more info on the types of Vibration we will be
trying to identify (Frequency and Amplitude).
Chris
On 11/01/2012 21:06, Jerry Scharf wrote:
Sorry, I had to jump in.
Accelerometers are not good at measuring vibration. Accelerations are
measured instantaneously and are designed to operate above the noise
floor of the sensor. The accelerometers have filters to remove the
noise to give less erratic readings. The filters are a best guess by
the designer of the maximum meaningful rate of acceleration change
(jerk) vs the amount of noise to allow through. Most tend to lean
toward heavily smoothed readings.
Vibration sets the noise floor of acceleration in rough terms. You
need something that internally integrates the various frequencies of
noise into RMS and peak vibrational energy measurements. Depending on
what you want, it is often better to measure the vibration in multiple
frequency bands.
My guess the specific reading regimens are driven by the military and
space applications areas, they are the most demanding/knowledgeable
about the area. Things shake quite a bit on rockets and ships, and the
equipment needs to be able to survive that. I have never needed to
deal with this, but can get more information from a friend if others
want it. At higher frequencies, it becomes audio noise and then it's a
whole different set of techniques and constraints (microphones, SPL
meters.)
jerry
On 01/11/2012 02:14 AM, Mick Sulley wrote:
I have not actually tried it, but the Wii remote has accelerometers
inside, that may be a cheaper source than buying the components.
Mick
On 11/01/12 06:35, Chris Lautre wrote:
Hi
Thanks for all your suggestions. Yes will use the DS2438.
I am looking at some accelerometers that give out 4-20mA.
Seem to be very expensive.
Will continue looking for a cheaper sensor.
Chris
On 10/01/2012 20:57, Mark Richards wrote:
On 1/10/2012 13:07, Chris Lautre wrote:
I am thinking along the lines of finding a sensor that produces 4-20mA and
using a DS2450 to convert to 1 Wire.
You might consider a DS2438 and using the current sense pins...
As others have stated, the 2450 is done for.
How would you implement the sensor portion? Accelerometer?
Intriguing..
/m
------------------------------------------------------------------------------
Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex
infrastructure or vast IT resources to deliver seamless, secure access to
virtual desktops. With this all-in-one solution, easily deploy virtual
desktops for less than the cost of PCs and save 60% on VDI infrastructure
costs. Try it free!http://p.sf.net/sfu/Citrix-VDIinabox
_______________________________________________
Owfs-developers mailing list
Owfs-developers@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/owfs-developers
------------------------------------------------------------------------------
Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex
infrastructure or vast IT resources to deliver seamless, secure access to
virtual desktops. With this all-in-one solution, easily deploy virtual
desktops for less than the cost of PCs and save 60% on VDI infrastructure
costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox
_______________________________________________
Owfs-developers mailing list
Owfs-developers@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/owfs-developers
------------------------------------------------------------------------------
RSA(R) Conference 2012
Mar 27 - Feb 2
Save $400 by Jan. 27
Register now!
http://p.sf.net/sfu/rsa-sfdev2dev2
_______________________________________________
Owfs-developers mailing list
Owfs-developers@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/owfs-developers