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I remember a discussion about posting files but I don't remember the outcome. I have a concept fish in JPEG format I'd like too discuss with every one.
Tod
Tod
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Re: Posting JPEGs - Let's give it a try
[img]../images/fish1.jpg[/img]
From Tod:
First the fish.
The idea is to have a leading edge at an angle so that if it hits something it tends to deflect up. Tow cable is configured so that at a given cable angle the fish is neutral. In a small boat, waves tend to raise and lower the fish, here when the boat pulls on the fish, do to a wave, it tends to make the fish dive and when the cable goes slack the fish try's to climb. This is accomplished by weighting the head in relation to the angle of the tow line and tail pivot. If you wanted to add other sensors, they could be mounted to the bottom of the head.
Now the transducers.
Jan was correct on his thought of the lights crossing and making a bright spot. Some fish use arrays of rectangles, 1.5 X .1 X .2 inches. These rectangular piezo elements are arranged in a slight arc to focus the beam. They might have several of these arcs using several hundred elements in total. Through electronics and software they are able too create a better 3D image doing some sort of frequency shifting or something like that,( that part is a mystery to me). When using puck style piezo elements it might be beneficial to arrange in an arc, like the big boys do. Other wise it doesn't matter how you arrange them. I would like to do a single arc array with the rectangular piezo elements. That would give use good beam angles. On the head of the fish you can see the exaggerated arc where either the puck or rectangular piezo elements could be. I got most of this information from Piezo Kinetics Inc. in Bellefonte, PA USA. I'm waiting for a quote from them on both types of elements.
Sincerely,
Tod -
Fish2.jpg
[img]../images/fish2.jpg[/img]
fish2...Comment
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Fish3.jpg
[img]../images/fish3.jpg[/img]
fish3...Comment
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How about that, Christian?!!
Ha! Dang code actually works!
HOWEVER... I do not have a check in place for image size yet. Tod's fish images were 1100x850 which is too big for the 600-pixel wide format of the forum so I scaled them down by 50%.
If you are uploading images please make sure they are 600 pixels wide or less. Height does not matter. There is a 128K limit on file size, although I can bump that up if it's a problem.
Thanks for those JPEGs Tod!
- CarlComment
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Re: This might be the answer, at last no sleepless nights anymore
>From Tod:
>First the fish.
>The idea is to have a leading edge at an angle so that if it hits something it tends to deflect up. Tow cable is configured so that at a given cable angle the fish is neutral. In a small boat, waves tend to raise and lower the fish, here when the boat pulls on the fish, do to a wave, it tends to make the fish dive and when the cable goes slack the fish try's to climb. This is accomplished by weighting the head in relation to the angle of the tow line and tail pivot. If you wanted to add other sensors, they could be mounted to the bottom of the head.
>Now the transducers.
>Jan was correct on his thought of the lights crossing and making a bright spot. Some fish use arrays of rectangles, 1.5 X .1 X .2 inches. These rectangular piezo elements are arranged in a slight arc to focus the beam. They might have several of these arcs using several hundred elements in total. Through electronics and software they are able too create a better 3D image doing some sort of frequency shifting or something like that,( that part is a mystery to me). When using puck style piezo elements it might be beneficial to arrange in an arc, like the big boys do. Other wise it doesn't matter how you arrange them. I would like to do a single arc array with the rectangular piezo elements. That would give use good beam angles. On the head of the fish you can see the exaggerated arc where either the puck or rectangular piezo elements could be. I got most of this information from Piezo Kinetics Inc. in Bellefonte, PA USA. I'm waiting for a quote from them on both types of elements.
>Sincerely,
>Tod
Tod,
Very impressing.
For the last few days I have been thinking very hard on the best possible form for my fish.
Had just 2 hours of sleep last night... :<
Never had the feeling that I got the best shape.
Either to complicated or to instable.
I think your idea gave me the idea I was looking for.
If you do not mind I will steal some parts of your idea.
As you have seen in previous posts I want my fish to be controlled from the boat since I want to add a camera to the fish.
I was stuck with the basic thinking of a wing on either side of the fuselage.
I thought about aileron system or whole wing movement (like in F16 Height(?) rudders)
The thing that worried me was that the whole body of the fish would change its angle. (Nose Up or Nose down)
When that happens the sonar will change its angle and thus the image would blurr
One might compensate that with software but that was making things to complex.
With your idea I could do it differently.
I let the wing hinge on the fuselage as you do.
The angle of the wing will be controlled by servo.
So with the wing I can control the depth.
Now it is just a matter of keeping the hinged fuselage horizontal
This can be done with the rudders on the tail.
Presto... I can control depth without changing the angle the fuselage.
Since I was not planning to do acrobatics, the angle of the wing will have only slight movements.
This will also stop oscillating
I think this will work.
This is exactly what I was hoping for when I suggested to use this forum to build a sonar.
Get good ideas from all over the world.
Just an hour ago I asked my girlfriend to build me a test tank...
Sounds perhaps funny, but I believe women can also use tools as long as someone takes the effort to teach them.
She already build my outboard rinse tank, and it works perfect ! (Only I would have used a different color to paint it.... hehe )
Anyway, she agreed to build it in about 2 weeks.
(We spend last sunday looking for a specific wreck without finding it... she is now also convinced a sidescan might come in handy .. hehe)
In the mean time I can build a simple scale model
Then I will do some tests with the model just to see if the principle works.
Provided that the waterpump I intend to use supplies enough water to create a large enough current in the tank...
When I have some test data I will post it.
I am quite exited about this !
Regard,
JanComment
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Re: How about that, Christian?!!
Hi Carl!
First of all let me say that it's been a pleasure following the discussion on the SSS.
Seems as sth. might really come out ofd this project!
I'm looking forward to reading more on it!
>HOWEVER... I do not have a check in place for image size yet. Tod's fish images were 1100x850 which is too big for the 600-pixel wide format of the forum so I scaled them down by 50%.
The upload just seems to work excellent. Once there was an automatic size check combined with an automatic resize function, we would have the web's most advanced discussion script.
I think this upload function is a great mean!
Best wishes,
ChristianComment
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