To tell if an engine is running or not what about monitoring oil or
fuel pressure?

For the pitch and roll, I don't think an accelerometer is not going to
do it. It will give you rate of change. You could do some math and get
degrees but it would not be accurate if the rate was different the
next time you had a pitch or roll.

A gyro would be best.
The pendulums attached to a potentiometer will work. I saw one that a
friend made from an old joystick for a computer. It has two pots in
it. He removed the joystick and attached a weighted pendulum in its
place. Putting that in a jug of light oil would make it more stable.
Can hook directly to computer input.

Regards
Gary


On Tue, 06 Jan 2004 19:52:27 +0800, Dave Baker
wrote:

On Tue, 06 Jan 2004 10:34:51 GMT, "Vic Fraenckel"
wrote:

I suspect that you are looking for a ready-made solution for measuring
pitch/roll. Perhaps something exists out there but I suspect that the price
would be high.

Yeah, basically (unless really necessary), I'm looking for something
ready-made. I need 2 units & they need to get installed on 2 ocean going
ships for about 2 or 3 months for some testing of satellite transceiver
performance vs sea state, so it's important that it works properly - I won't
be able to go & make service calls! :-) It will need to be reliable as well
as accurate to a degree or so over the expected pitch/roll range of the
vessel.

There is a solid state sensor that is a two axis accelerometer made by
Analog Devices. It is the ADXL202 chip

Coincidentally I have one sitting on my desk at the moment - one of those
projects that got started but not finished. I was looking at using these
accelerometers to strap to engine blocks on boats to determine whether the
particular engine was running or not - we had a client that wanted monitoring
of engine hours for 4 diesel propulsion engines & 2 diesel generators on a
boat. I thought that I might be able to strap these units onto the engine
blocks of each engine & get at least an on/off indication, and maybe as a
bonus an RPM count. I hadn't considered using them as pitch/roll sensors
before. Calibration would be the hard part.

I've seen some good rate sensors at
http://www.atasensors.com/Sensors2/index.htm
and have toyed with somehow getting pitch & roll from these, but don't
actually know how to do that yet - integration or something similar I guess?
The sensors themselves have good characteristics - fast response, etc. It
would definitely be nice to find something that provided pitch & roll in
RS232 format without any work on my part. :-)

Dave