mini doppler radar or ?
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Posts: 46,084
I have an application for a small speedometer on a canoe. I am working with
a couple of constraints:
#1. I need speed through the water so a GPS won't work.
#2. I need to be able to attach and detach it in a minute or so (nothing
permanent on the canoe).
My thinking is a mini doppler radar hanging on the gunwale looking forward
at, say, a 45% angle (like a police speed gun) that only needs a range of,
say, three feet.
I am also thinking about the possibility of a small camera looking down and
measuring the speed of the water passing the hull.
Since I have never worked with either of these technologies, I have no idea
whether either of these ideas are possible or practical. I know there a lot
of bright guys on this list. Any comments or suggestions would be
appreciated.
Jay
a couple of constraints:
#1. I need speed through the water so a GPS won't work.
#2. I need to be able to attach and detach it in a minute or so (nothing
permanent on the canoe).
My thinking is a mini doppler radar hanging on the gunwale looking forward
at, say, a 45% angle (like a police speed gun) that only needs a range of,
say, three feet.
I am also thinking about the possibility of a small camera looking down and
measuring the speed of the water passing the hull.
Since I have never worked with either of these technologies, I have no idea
whether either of these ideas are possible or practical. I know there a lot
of bright guys on this list. Any comments or suggestions would be
appreciated.
Jay
Comments
no idea
> whether either of these ideas are possible or practical. I know
there a lot
> of bright guys on this list. Any comments or suggestions would be
> appreciated.
Are you trying to track the speed of the boat you're in relative to
the land, the speed of the water against the boat, the speed of the
boat relative to the water, the speed of the water relative to the
land, the speed of another boat relative to your boat, the speed of
another boat relative to the land, the speed of another boat relative
to the water around your boat, the speed of another boat relative to a
stationary object such as a buoy, the speed of another boat relative
to a buoy versus the speed of the water relative to the land, or the
speed of a boy in a boat trying to escape his relatives?
Eh, what are you trying to track?
-Chilton
working with
> a couple of constraints:
>
If you're just looking for a speedometer, you could trail a
'mini-torpedo' and have it track its speed through the water. That
would be possible by measuring the speed of a tail rotor at the end of
the torp, and having a stamp average out the rotations per minute over
a period of time, then apply some mathematical formula I learned in
the 6th grade and promptly forgot. That should do it, and it would be
very portable (ie you could take your torpedo elsewhere).
-Chilton
stern and transmit the speed 20 feet forward to a display...
I will have to thimk about that for a bit...
Jay
Original Message
From: chilton@t... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=drCFSVXbIwgL4601l3rjTyafHEncy1WIhdcsU_WHk8-HQDne2IRLm3g_ChovxT_CD6jz2oCXuUg]chilton@t...[/url
Sent: Sunday, June 17, 2001 1:00 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] mini doppler radar or ?
> I have an application for a small speedometer on a canoe. I am
working with
> a couple of constraints:
>
If you're just looking for a speedometer, you could trail a
'mini-torpedo' and have it track its speed through the water. That
would be possible by measuring the speed of a tail rotor at the end of
the torp, and having a stamp average out the rotations per minute over
a period of time, then apply some mathematical formula I learned in
the 6th grade and promptly forgot. That should do it, and it would be
very portable (ie you could take your torpedo elsewhere).
-Chilton
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paddle wheel with magnets in the paddles. Say 4 paddles, Then count
pulses. Cheap and effective. Only let part of the paddel be
effected by the flowing water and it will spin easily.
google search gave me this....
"paddle wheel flow sensor"
http://www.fireresearch.com/paddle.htm
--- In basicstamps@y..., "Jay Hanson" <j@q...> wrote:
> I have an application for a small speedometer on a canoe. I am
working with
> a couple of constraints:
>
> #1. I need speed through the water so a GPS won't work.
>
> #2. I need to be able to attach and detach it in a minute or so
(nothing
> permanent on the canoe).
>
> My thinking is a mini doppler radar hanging on the gunwale looking
forward
> at, say, a 45% angle (like a police speed gun) that only needs a
range of,
> say, three feet.
>
> I am also thinking about the possibility of a small camera looking
down and
> measuring the speed of the water passing the hull.
>
> Since I have never worked with either of these technologies, I have
no idea
> whether either of these ideas are possible or practical. I know
there a lot
> of bright guys on this list. Any comments or suggestions would be
> appreciated.
>
> Jay
a canoe.........
I like the "torpedo" idea. Only drawback I see
is....where you're going, are there any fish big
enough to think the torpedo is lunch? One thought
I had was a variable resistance stress sensor.
These are strips of plastic with a resistive
coating which would change value when flexed by
the water going by. I'm not sure if they're water
proof, but you'd probably want to bond it to a
stiffer backing and stick that in the water.
Calibration would be the only problem I see, but
you'd have that with the torpedo, too. I forget
who had these, maybe someone else on the list
recalls. I'll try to find out and let you know.
--Stu Wrenn
wheel. 10.00 for aluminum pole 4.00 for a c-clamp to
mount to the boat
Eric Haskins
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Seems like it would be ideal.
Dale Harwood [noparse][[/noparse] N4VFF ]
internet> dale@h...
ax.25> n4vff@n4vff.#cha.tn.usa.noam
#include <std_disclaimer.h>
The flex sensor I mentioned earlier is described at:
http://www.imagesco.com/catalog/flex/FlexSensors.html
--Stu
#1. It's not my boat. I can't mount anything permanently. We don't even
know which canoe we are going to use until it's in the water.
#2. I can't slow the boat down by dragging too much stuff through the water
(although a little torpedo would be OK).
#3. Six paddlers sweep both sides of the canoe in front of them. This
disturbs the water flow and will destroy anything in the way of the paddles.
The bow, stern, and about six inches next to each paddler is available.
#4. The electronics must survive immersion in salt water (these canoes
capsize quite a bit). Waterproof to a depth of, say, one foot would be all
that was needed.
I had toyed with the idea of a propeller before, but the immersion problem
(machining, O rings, etc.) seemed to present quite a challenge. I do not
have a lathe or milling machine.
If a camera could peer out of a clear plastic window and estimate the speed
of the passing water, then it would be a lot easier in some ways. But I
suspect the processing demands would be horrendous.
Jay
Original Message
From: Eric Haskins [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=gE_VPduYS5FElu0as1bLsLceVYAzIZQ7YFoU75uAhXmkG_S6qGsDpvd6SMzDZ5cZakUBsiO5Feyi6f8aGrlzng]wirelesstech71@y...[/url
Sent: Monday, June 18, 2001 3:14 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] mini doppler radar or ?
35.00 @ westmarine.com No sense in reinventing the
wheel. 10.00 for aluminum pole 4.00 for a c-clamp to
mount to the boat
Eric Haskins
__________________________________________________
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Jay
Original Message
From: Stu Wrenn [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=iVa39fzCw_80_0txZAHL4j89qsec7XlpvqIDPoJG9FOyuF2xfl4TuBgiY8MyJAZMbSXTpQn28Im_ig]swrenn@z...[/url
Sent: Monday, June 18, 2001 6:03 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] mini doppler radar or ?
Found it!
The flex sensor I mentioned earlier is described at:
http://www.imagesco.com/catalog/flex/FlexSensors.html
--Stu
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boat (doesn't need to be propellored) with an attached string
to a device inside the boat. Measure the force of the drag
from inside the boat, higher drag = faster through the water.
you are really measuring the water pressure against the object
as the boat moves forward...
Just a thought.
with enough thrust, pigs fly just fine.
---- On Mon, 18 Jun 2001, Jay Hanson (j@q...) wrote:
> The problems with these kinds of solutions are basically four:
>
> #1. It's not my boat. I can't mount anything permanently.
We don't
> even
> know which canoe we are going to use until it's in the water.
>
> #2. I can't slow the boat down by dragging too much stuff
through the
> water
> (although a little torpedo would be OK).
>
> #3. Six paddlers sweep both sides of the canoe in front of
them. This
> disturbs the water flow and will destroy anything in the way
of the
> paddles.
> The bow, stern, and about six inches next to each paddler is
available.
>
> #4. The electronics must survive immersion in salt water
(these canoes
> capsize quite a bit). Waterproof to a depth of, say, one
foot would be
> all
> that was needed.
>
> I had toyed with the idea of a propeller before, but the
immersion
> problem
> (machining, O rings, etc.) seemed to present quite a
challenge. I do
> not
> have a lathe or milling machine.
>
> If a camera could peer out of a clear plastic window and
estimate the
> speed
> of the passing water, then it would be a lot easier in some
ways. But I
> suspect the processing demands would be horrendous.
>
> Jay
>
>
Original Message
> From: Eric Haskins [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=5Wk6pqx79gf6UNo7SPGm_pwhFxDdAxycRHVAA34ajWdUZFk9m3UvUIZl2PaeYc0m30VxPiTfVrguHea2d-2SfA]wirelesstech71@y...[/url
> Sent: Monday, June 18, 2001 3:14 AM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] mini doppler radar or ?
>
>
> 35.00 @ westmarine.com No sense in reinventing the
> wheel. 10.00 for aluminum pole 4.00 for a c-clamp to
> mount to the boat
>
> Eric Haskins
>
>
>
>
> __________________________________________________
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>
>
the boat, that is, the current?
If you measured the boat movement vs the water speed in a kayak on water in
a fast moving stream, you wouldn't get anywhere the correct real speed.
At 05:05 PM 6/18/2001 -0400, you wrote:
>How about a "drag" measure. Drag any small thing behind the
>boat (doesn't need to be propellored) with an attached string
>to a device inside the boat. Measure the force of the drag
>from inside the boat, higher drag = faster through the water.
>you are really measuring the water pressure against the object
>as the boat moves forward...
_________________________________
Mike Walsh
walsh@i...
would think, but depends on the needs. Currents etc. do their
thing vs. progress relative to land, but speed through the
water is irrepective of wind,currents, etc...
with enough thrust, pigs fly just fine.
---- On Mon, 18 Jun 2001, Mike Walsh (walsh@c...) wrote:
> Don't you need to consider the direction and speed of the
water flow
> around
> the boat, that is, the current?
> If you measured the boat movement vs the water speed in a
kayak on water
> in
> a fast moving stream, you wouldn't get anywhere the correct
real speed.
>
> At 05:05 PM 6/18/2001 -0400, you wrote:
> >How about a "drag" measure. Drag any small thing behind the
> >boat (doesn't need to be propellored) with an attached string
> >to a device inside the boat. Measure the force of the drag
> >from inside the boat, higher drag = faster through the water.
> >you are really measuring the water pressure against the
object
> >as the boat moves forward...
>
> _________________________________
> Mike Walsh
> walsh@i...
>
>
> To UNSUBSCRIBE, just send mail to:
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> Subject and Body of the message will be ignored.
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>
>
>
>
water moves- in the ocean, the waves move and the water stays
still in comparison. (from my canoeing days)
---- On Mon, 18 Jun 2001, Mike Walsh (walsh@c...) wrote:
> Don't you need to consider the direction and speed of the
water flow
> around
> the boat, that is, the current?
> If you measured the boat movement vs the water speed in a
kayak on water
> in
> a fast moving stream, you wouldn't get anywhere the correct
real speed.
>
> At 05:05 PM 6/18/2001 -0400, you wrote:
> >How about a "drag" measure. Drag any small thing behind the
> >boat (doesn't need to be propellored) with an attached string
> >to a device inside the boat. Measure the force of the drag
> >from inside the boat, higher drag = faster through the water.
> >you are really measuring the water pressure against the
object
> >as the boat moves forward...
>
> _________________________________
> Mike Walsh
> walsh@i...
>
>
> To UNSUBSCRIBE, just send mail to:
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> Subject and Body of the message will be ignored.
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speed-through-the-water, then I can calculate currents (which can be a knot
or more).
Jay
Original Message
From: Mike Walsh [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=omOb8yzb-t_J7aNeCCQMWEQr5kpcE9jELPSI5dTDm8xPoR1d1K7icpkbnDOvFTjJv4oCAhjShuw947_g]walsh@c...[/url
Sent: Monday, June 18, 2001 11:14 AM
To: basicstamps@yahoogroups.com
Subject: Re: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
Don't you need to consider the direction and speed of the water flow around
the boat, that is, the current?
If you measured the boat movement vs the water speed in a kayak on water in
a fast moving stream, you wouldn't get anywhere the correct real speed.
At 05:05 PM 6/18/2001 -0400, you wrote:
>How about a "drag" measure. Drag any small thing behind the
>boat (doesn't need to be propellored) with an attached string
>to a device inside the boat. Measure the force of the drag
>from inside the boat, higher drag = faster through the water.
>you are really measuring the water pressure against the object
>as the boat moves forward...
_________________________________
Mike Walsh
walsh@i...
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I am still a bit confused about what you really want to measure?
You say you want to measure the amount of water passing the canoe.
Scenario 1: in a river if you go with the flow (no paddling) you would
measure zero amount.
Scenario 2: in a river paddling downstream you would measure a positive
amount while going faster than the water
Scenario 3: in a river paddling upstream to keep the canoe 'on the spot',
you would measure a positive amount also.
So I do not see how the amount of passed water gives you any practical
information about what is happening
without additional info like upstream/downstream paddling etc.
Please elaborate a bit more what you want to measure.
Greetings peter
> (machining, O rings, etc.) seemed to present quite a challenge. I do not
> have a lathe or milling machine.
Edmund Scientific sells a little plastic motor/prop. You could remove the
battery and use the motor as a generator. Or you could replace the motor
with some kind of sensor (optical, magnetic) and count the revolutions.
Put your stamp in the plastic container. Water tight! If you need more
than data logging, (ie display), you can drill a hole and silicon in a
wire, or go high tech, use a wireless transmitter.
I looked through the entire ES website, haven't found it. If you have one
of their catalogs, it looks like a torpedo, red and white in color, with a
suction cup on the side. I think it runs off of one or two AA batteries.
> If a camera could peer out of a clear plastic window and estimate the
> speed of the passing water, then it would be a lot easier in some ways.
> But I suspect the processing demands would be horrendous.
This is precisely what all the _new_ optical mice do. It was developed by
an engineer at HP. (ie. Logitech, Microsoft and Kensignton. NOT the old
Sun mice from Mouse Systems.) You can pick them up for $20 - $30.
Warning. The mouse I have only works at a distance of about 1/4". This
may be adjustable by using different optics and lighting. I have not tried
this kind of modification.
joshua
>If this were for training I could see how this would be great, showing how
>much work was being done.
>They could be working there butts off and standing still just like a
>exercise bike they have spedo's but don't go anywhere ??
True, but my mentioned scenario's 2 and 3 could result in the same amount
measered,
while scenario 2 requires a lot less 'work' as gravity helps you.
So I do need additional info to get the 'real' results.
Greetings peter
much work was being done.
They could be working there butts off and standing still just like a
exercise bike they have spedo's but don't go anywhere ??
Peter Verkaik wrote:
>
> Hi,
>
> I am still a bit confused about what you really want to measure?
> You say you want to measure the amount of water passing the canoe.
>
> Scenario 1: in a river if you go with the flow (no paddling) you would
> measure zero amount.
>
> Scenario 2: in a river paddling downstream you would measure a positive
> amount while going faster than the water
>
> Scenario 3: in a river paddling upstream to keep the canoe 'on the spot',
> you would measure a positive amount also.
>
> So I do not see how the amount of passed water gives you any practical
> information about what is happening
> without additional info like upstream/downstream paddling etc.
>
> Please elaborate a bit more what you want to measure.
>
> Greetings peter
>
> To UNSUBSCRIBE, just send mail to:
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>..... Seems like it would be ideal.
The main reason is that GPS gives speed-over-bottom rather than
speed-through-water. With both, I can calculate currents.
Also, my GPS only gives speed once a second. I need faster updates (e.g.,
10 hz) so I can, among other things, measure the stroke rate.
Jay
>>the speed of the passing water, then it would be a lot easier in
>
>This is precisely what all the _new_ optical mice do. It was
>developed by an engineer at HP. (ie. Logitech, Microsoft and
>Kensignton. NOT the old Sun mice from Mouse Systems.) You
>can pick them up for $20 - $30. Warning. The mouse I have
>only works at a distance of about 1/4". This may be adjustable
>by using different optics and lighting. I have not tried
>this kind of modification.
GREAT IDEA! I hadn't thought about mice. The same concept extended to a
longer range (say, two feet) and a different reflective surface...
Jay
is not very reliable for estimating velocity. Been there, done that.
Dennis
Original Message
From: Ken Ambrose [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=WNfTfekV09eHvPLChGXj7CpLEXswGdG7bg8qkJxHk7y_Dg4mYk7oMoFq61eyeXlN5tAinvsQe_A]kenzo@u...[/url
Sent: Monday, June 18, 2001 2:40 PM
To: Mike Walsh
Subject: Re: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
Not really. Speed through the water is the most meaningful I
would think, but depends on the needs. Currents etc. do their
thing vs. progress relative to land, but speed through the
water is irrepective of wind,currents, etc...
with enough thrust, pigs fly just fine.
---- On Mon, 18 Jun 2001, Mike Walsh (walsh@c...) wrote:
> Don't you need to consider the direction and speed of the
water flow
> around
> the boat, that is, the current?
> If you measured the boat movement vs the water speed in a
kayak on water
> in
> a fast moving stream, you wouldn't get anywhere the correct
real speed.
>
> At 05:05 PM 6/18/2001 -0400, you wrote:
> >How about a "drag" measure. Drag any small thing behind the
> >boat (doesn't need to be propellored) with an attached string
> >to a device inside the boat. Measure the force of the drag
> >from inside the boat, higher drag = faster through the water.
> >you are really measuring the water pressure against the
object
> >as the boat moves forward...
>
> _________________________________
> Mike Walsh
> walsh@i...
>
>
> To UNSUBSCRIBE, just send mail to:
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> Subject and Body of the message will be ignored.
>
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>
>
>
>
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Original Message
From: Ken Ambrose [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ZQEPg26rLbEKcCbqtX3Vui5Da25uZC8FsLz78AHLkXv-CiPiZPMIOfiMZqQlWsP_qYRixDTnyG4]kenzo@u...[/url
Sent: Monday, June 18, 2001 2:05 PM
To: Jay Hanson
Subject: Re: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
with enough thrust, pigs fly just fine.
Ken,
Thrust without guidance is called a free-fall trajectory. The result is
called SPLAT [noparse]:)[/noparse] .
Dennis
have gone "ballistic", as in bullet...
[noparse]:)[/noparse]
everything should be made as simple as possible, but no simpler.
---- On Mon, 18 Jun 2001, Dennis P. O'Leary
(doleary@h...) wrote:
>
Original Message
> From: Ken Ambrose [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Gv4RvskFp1WsV45sO7YHCKGxgszjswLgNzjp5uwLE3KVCqNPif8HGwl7V-t-ukXH88pFRvmfxQ]kenzo@u...[/url
> Sent: Monday, June 18, 2001 2:05 PM
> To: Jay Hanson
> Subject: Re: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
>
> with enough thrust, pigs fly just fine.
>
> Ken,
>
> Thrust without guidance is called a free-fall trajectory.
The result is
> called SPLAT [noparse]:)[/noparse] .
>
> Dennis
>
>
>
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>
>
>
is NMEA (like a GPS) which is easy to read, or pulse output, also easy to
read. The transducer is minimally intrusive, and mounts easily on a
temporary bracket.
http://www.airmar.com/whatsnew/cs4500-1.html
William Thompson
Original Message
From: Jay Hanson [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=uTWAoqaOIrVnt55FheOGQ7OGapmZ0LyaUV9B1nw4iVdOrjbpfQfqqzDusQYwEYmZPoL1]j@q...[/url
Sent: Monday, June 18, 2001 6:03 PM
To: basicstamps@yahoogroups.com
Subject: RE: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
I can get speed over the bottom with a GPS. If compare the GPS with
speed-through-the-water, then I can calculate currents (which can be a knot
or more).
Jay
Original Message
From: Mike Walsh [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=sMWwYnKs9M-kFw3REwD-B1usi_fCaLGFQB8g7xoCatfPNtLvgniSw8Zj_YkmvVPJFiuVt-DSvp8Mv6IU]walsh@c...[/url
Sent: Monday, June 18, 2001 11:14 AM
To: basicstamps@yahoogroups.com
Subject: Re: RE: [noparse][[/noparse]basicstamps] mini doppler radar or ?
Don't you need to consider the direction and speed of the water flow around
the boat, that is, the current?
If you measured the boat movement vs the water speed in a kayak on water in
a fast moving stream, you wouldn't get anywhere the correct real speed.
At 05:05 PM 6/18/2001 -0400, you wrote:
>How about a "drag" measure. Drag any small thing behind the
>boat (doesn't need to be propellored) with an attached string
>to a device inside the boat. Measure the force of the drag
>from inside the boat, higher drag = faster through the water.
>you are really measuring the water pressure against the object
>as the boat moves forward...
_________________________________
Mike Walsh
walsh@i...
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> That might work. Because of the paddles, I would have to trail it off the
> stern and transmit the speed 20 feet forward to a display...
This may be too late...
We had some EG&G sidescan units & recorders. The recorders had an
input for something called a "speed log". There was a small device about
the size of an egg, with an impellor (impeller?). I believe it had a magnet or
2 & a reed switch, and just sent pulses back to the sidescan recorder. It
had about 30 metres of coax cable & you just threw it over the side
somewhere out of the wake (we used an outrigger pole) & plugged the
other end into the recorder.
The speed pulses were used to control the speed of the paper moving
through the recorder. It seemed pretty accurate for our purposes, but
could be calibrated to give better results I guess. I can't find anything on
this particular model on the Internet, but doing a search on "speed log"
turns up 37 matches - some of them might be ok. Of course if you want to
get really technical you need a 2 axis device which means going to doppler
or similar - getting more expensive & bulky. The impellor gave very little
drag.
Dave