Does anyone know of a pitch & roll sensor suitable for installation on a
vessel? I need to log pitch & roll on a boat & compare it with signal
strength from a satellite receiver, so I need a sensor that will output as
USB for me to connect to a notebook & log it, along with signal strength data
from the satellite receiver.

If necessary I could use an RS232 sensor. I'm hoping for something reasonably
cheap. Definitely less than US$500.

Dave

On Thu, 18 Sep 2003 15:16:54 +0800, Dave Baker wrote:

Does anyone know of a pitch & roll sensor suitable for installation on a
vessel? I need to log pitch & roll on a boat

I'll have another go at this, seeing that I didn't get an answer a while
back, and some units that I have found since have turned out to be
unsuitable.

Anyone know of any pitch/roll sensors that are designed specifically for
measuring pitch & roll in vessels? The units that I have found apparently are
more for static applications, and are affected by acceleration, so are not
accurate in dynamic situations.

I'd settle for any USB or serial output, and if absolutely necessary then I'd
go for 4-20mA output & shove a converter on the end.

Dave

Dave,

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. If you are looking for something ready-to-go I can't help
you. If you have some electronic skills and some programming skills you can
build something that will work and most likely be way less costly than the
ready-made solutions.

There is a solid state sensor that is a two axis accelerometer made by
Analog Devices. It is the ADXL202 chip and you can find numererous
references to it with a google search on the part number. I have been
experimenting, on and off, with the device and a microprocessor for several
years and find it rather easy to interface and get working.

I am in the process of selling my home and plan to live-aboard and I have
sort of thought that a pitch/roll sensor would be a neat thing to do for a
"boat project" and I will visit this when I get set up on a boat. I would
consider a project of this type to be relatively simple to accomplish if one
had some electronic skills. All it would take is a ADXL, a simple micro and
a LCD display device and some programming to prototype a working instrument.

HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
vfraenc1 ATSIGN nycap DOT rr DOTcom
KC2GUI

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

| On Thu, 18 Sep 2003 15:16:54 +0800, Dave Baker
wrote:
|
| Does anyone know of a pitch & roll sensor suitable for installation on a
| vessel? I need to log pitch & roll on a boat
|

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

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

Here's a link that might be useful, I don't know what the prices are like.

http://www.datawell.nl/products_motion_sensors.html

Dennis

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

"Gary Schafer" wrote
|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.
|

This is NOT correct. The ADXL is NOT measuring rate of change. It's output
measures the gravitational acceleration directly. I suggest that you read
AMD's data sheet on this product to understand how it works. I have used the
ADXL to measure the inclination of a telescope tube with some success.

Regards,

Vic
--
__________________________________________________ ______

Victor Fraenckel - The Windman
vfraenc1 ATSIGN nycap DOT rr DOTcom
KC2GUI

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)
|

Oddly enough, my goals are the same. I intend to retire this spring, and buy a boat for coastal
cruising. One project I have in mind is a "wave-meter", i.e., a device which will tell me how high
the waves are....swells and wind chop. Roll and pitch should be do-able also.

My approach is the same as below. But, as pointed out in another post, calibration is the problem.

I'll follow this thread with a great deal of interest.

Norm

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

Dave,

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. If you are looking for something ready-to-go I can't help
you. If you have some electronic skills and some programming skills you can
build something that will work and most likely be way less costly than the
ready-made solutions.

There is a solid state sensor that is a two axis accelerometer made by
Analog Devices. It is the ADXL202 chip and you can find numererous
references to it with a google search on the part number. I have been
experimenting, on and off, with the device and a microprocessor for several
years and find it rather easy to interface and get working.

I am in the process of selling my home and plan to live-aboard and I have
sort of thought that a pitch/roll sensor would be a neat thing to do for a
"boat project" and I will visit this when I get set up on a boat. I would
consider a project of this type to be relatively simple to accomplish if one
had some electronic skills. All it would take is a ADXL, a simple micro and
a LCD display device and some programming to prototype a working instrument.

HTH

Vic

wrote in message
...
| Oddly enough, my goals are the same. I intend to retire this spring, and
buy a boat for coastal
| cruising. One project I have in mind is a "wave-meter", i.e., a device
which will tell me how high
| the waves are....swells and wind chop. Roll and pitch should be do-able
also.
|
| My approach is the same as below. But, as pointed out in another post,
calibration is the problem.
|

Norm,

There is no calibration problem with the ADXL202. What is a problem, at
least with my application, is insuring that the accelerometer is mounted
perpendicular to the roll and pitch axes. I am attempting to mount the ADXL
on a telescope (not astronomical) to measure the inclination of the optical
axis of the system. After trying to align the accelerometer mrchanically to
the axes, I am now trying to write a routine to compute the off-axisness and
use the results to compensate for the mis-alignment.

To understand the ADXL go to the AMD site http://www.amd.com/us-en/ and
download the ADXL202 data sheets. There are also some app notes that are
interesting.

You might also explore U.S. Digital http://www.usdigital.com/ as they have
an inclinometer that might do the trick. Check out the T6 unit. I have used
their shaft encoder products and am seriously considering the T6.



HTH

Vic

--
__________________________________________________ ______

Victor Fraenckel - The Windman
vfraenc1 ATSIGN nycap DOT rr DOTcom
KC2GUI

Home of the WindReader Electronic Theodolite
Read the WIND

"Victory at all costs, victory in spite of all terror, victory however long
and hard the road may be; for without victory there is no survival."
- Winston [Leonard Spencer] Churchill (1874 - 1965)

Dost thou not know, my son, with how little wisdom the world is governed?
-Count Oxenstierna (ca 1620) to the young King Gustavus Adolphus

On Tue, 06 Jan 2004 20:27:08 GMT, "Vic Fraenckel" wrote:

wrote in message
.. .
| Oddly enough, my goals are the same. I intend to retire this spring, and
buy a boat for coastal
| cruising. One project I have in mind is a "wave-meter", i.e., a device
which will tell me how high
| the waves are....swells and wind chop. Roll and pitch should be do-able
also.
|
| My approach is the same as below. But, as pointed out in another post,
calibration is the problem.
|

Norm,

There is no calibration problem with the ADXL202. What is a problem, at
least with my application, is insuring that the accelerometer is mounted
perpendicular to the roll and pitch axes. I am attempting to mount the ADXL
on a telescope (not astronomical) to measure the inclination of the optical
axis of the system. After trying to align the accelerometer mrchanically to
the axes, I am now trying to write a routine to compute the off-axisness and
use the results to compensate for the mis-alignment.

Have you considered integrating the signal? I'd suspect that on average,
"up" would be the 'average' of the roll and pitch over a period of time.
Interesting engineering problem.

I'll check out usdigital's web site...thanks.

snip


HTH

Vic