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.
<https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/830M1-2000/14118098>
Anybody used them?
Cheers
Phil Hobbs
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.
<https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/830M1-2000/14118098>
Anybody used them?
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.
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...
?
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
On Thu, 05 Sep 2024 06:22:04 GMT, Jan Panteltje <alien@comet.invalid>
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...
?
No, just measure the voltage or the charge that it generates under acceleration. It's a polarized, piezoelectric ceramic thing for 30
cents.
https://www.mouser.com/c/?q=ceramic%20resonator
One might also measure its resonant frequency vs acceleration.
I wonder how one would test it. At 2000 g's.
On Thu, 05 Sep 2024 07:07:25 -0700, john larkin wrote:
On Thu, 05 Sep 2024 06:22:04 GMT, Jan Panteltje <alien@comet.invalid>
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...
?
No, just measure the voltage or the charge that it generates under
acceleration. It's a polarized, piezoelectric ceramic thing for 30
cents.
https://www.mouser.com/c/?q=ceramic%20resonator
One might also measure its resonant frequency vs acceleration.
I wonder how one would test it. At 2000 g's.
Compare to a single expensive calibrated accelerometer? Not familiar with Measurement Specialties, other possibilities are:
https://www.kistler.com/INT/en/c/accelerometers/CG21-accelerometers https://buy.endevco.com/accelerometer
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.)full-scale range of 1000-2000 g would be about right.
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
None of the MEMS IC accelerometers go anywhere near that high. Measurement Specialties makes them, but they're $160 in onesies, e.g.
<https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/830M1-2000/14118098>
Anybody used them?
Cheers
Phil Hobbs
On 2024-09-05 00:30, Phil Hobbs 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.
<https://www.digikey.com/en/products/detail/te-connectivity-measurement-specialties/830M1-2000/14118098>
Anybody used them?
I've measured big fast forces using strain gauges.
If you can be sure the place where you place that on the metal rod stays elastic during the acceleration the bandwidth should not be a problem.
Now, computing a calibration and amplifying that signal is the next problem...
On 2024-09-05 11:10, Glen Walpert wrote:
On Thu, 05 Sep 2024 07:07:25 -0700, john larkin wrote:Thanks, Glen, good leads.
On Thu, 05 Sep 2024 06:22:04 GMT, Jan Panteltje <alien@comet.invalid>
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...
?
No, just measure the voltage or the charge that it generates under
acceleration. It's a polarized, piezoelectric ceramic thing for 30
cents.
https://www.mouser.com/c/?q=ceramic%20resonator
One might also measure its resonant frequency vs acceleration.
I wonder how one would test it. At 2000 g's.
Compare to a single expensive calibrated accelerometer? Not familiar with >> Measurement Specialties, other possibilities are:
https://www.kistler.com/INT/en/c/accelerometers/CG21-accelerometers
https://buy.endevco.com/accelerometer
The PCB Piezotronics folks (formerly Endevco) have the single-axis,
+-50k gees model 350D2 for $1200ish in onesies, which we may wind up buying.
Cheers
Phil
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