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B7gw000__ron Turchyniak
11-03-1993, 04:21 AM
I originally sent the following:

I would like to know if anyone knows what exactly is involved in
calibrating Forse sensitive resistor type transducers ?
(used in the EDG)

NB:
The transducers are force sensitive resistors that have a hyperbolic
resistance pressure relationship.
----------------------------
> I can probably answer my own question...I think Langer Biomech
must of used a load cell...found a paper by
(Hongsheng, Maalej,Webster, Tompkins, Bach-y-Rita, & Wertsch, 1988)
A microprocessor-based data acquisition system for monitoring foot
pressures
They calibrated sensors using a 440-N load cell as a reference
which used a piece-wise linear lookup table...which compensates
for the nonlinearity of the sensor
----------------------------
I also wrote:

The manufacturer (Langer Biomechanics) says that their new software
performs sensor calibrations, I would like to know what type (how)
of calibration is performed by the software ?

> I am not sure exactly what they do but I assume they translate
>the voltages into pressures by looking at prestored sensor
>calibration tables !


My next questions
-----------------
Are these sensors manufactured alike ?
How accurate are they ?
(I read 100-200 % variable for pressure)
Does anyone know where these sensors are manufacured ?
(The only company I have heard of is Interlink Electronics)

I encourage any general comments with respect to these types of
transducers, I am not familiar with the engineering that goes
into these transducers.
..are these FSR's temperature sensitive..
. or affected by shear or bending .. ?
What are the pros and cons of FSR type sensors ?

PS:
The reason I am asking these questions.. I have no control over the
calibrations... the EDG does them internally via the software
and I was asked to document the general concept of such a
calibration...and also because I have no documentation of the
characteristics of these specific sensors

Thanks in advance
Sincerely,
Ron
B7GW@MUSICB.MCGILL.CA