Re: Accelerometers for >1000g measurements

On 05/09/2024 07:22, Jan Panteltje wrote:

On a sunny day (Wed, 04 Sep 2024 19:57:04 -0700) it happened john larkin
<jlarkin_highland_tech> wrote in <md7idj1plqodnthuqpcemaphbrtotlqveh@4ax.com>:
 

On Wed, 4 Sep 2024 18:30:46 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

So for this customer gig I need to measure the actual acceleration of a
parallel-rod transmission line that's being pounded into the ground with
a built-in slide hammer.  (It's for measuring soil moisture and salinity
by TDR.)
>
We're thinking about putting the TDR pulser and sampler in the part that
gets pounded (in a potted module obviously), so knowing how bad the
acceleration gets is going to be important.  I expect that it'll be
several hundred g in volcanic soil, so a full-scale range of 1000-2000 g
would be about right.
>
None of the MEMS IC accelerometers go anywhere near that high.
Measurement Specialties makes them, but they're $160 in onesies, e.g.

  If you can make it emit some ultrasonic sound you can measure the received frequency shift from far away?
Same for RF likely...

Attach an adhesive label printed with a black and white wedge to
the rod.  Illuminate with uniform light and view with a photodiode
lens slit combination.  Capture the velocity waveform on 'scope.
Calibrate at low speed.
I expect the acceleration peak might only last a few microseconds
but could be many thousands of g.
John