I've read a lot of data sheets, Meindert, and so have you, I'm sure. Under
the right conditions, and applying a lot of knowledge of its limitations,
the device could be used as an inclinometer. But that's another topic. If
you constrain the boat to always be anchored, we get closer to an
application in which it could be used as an inclinometer, but again, that
seems to me to be another topic. I have, in fact, used similar(single axis)
accelerometers, but usually as vibration pickups. That particular
instrument is not a high-grade device, in spite of what you think you might
read from the data sheet. This class of device typically has a bias output
which, while capable of being calibrated, is often unstable and/or
temperature dependent, and/or g-sensitive. So when you say it is usable in
an application, you always must specify to what level of accuracy, etc.
And to use it as a generalized rotational sensor is a total misapplication.

And we weren't discussing horeshoes, so I do not consider "almost 1 g" to be
close enough.

Max Lynn

"Meindert Sprang" wrote in message
...
"maxlynn" wrote in message
news:9tXKb.103004$pY.50340@fed1read04...
What you say is true in a fixed one-g environment. You can derive a
crude
measurement of angular rotation in any fixed, uni-directional
acceleration
environment in the manner that you suggest. But as I understand the
proposed application, the accelerometer(s)/instruments are to be mounted
in
a dynamic environment. The accelerometers mentioned are designed to
measure
linear acceleration. That is what the manufacturer designed them to do.
They are NOT designed to measure rotation or rotational rates. That is
generally a domain reserved for gyroscopes and related insruments or
systems.

Well, read the datasheets. AD says specifically in their datasheets that
the
ADXL's can be used as an inclinometer. Apart from that, a boat seems an
'almost fixed' one-g environmet to me.

Meindert