Hi,
I checked around, but didn't quite find the correct answer.
What I'm interested case:
I have a pole, that I want to know, in what angle is it rotated to, but I'm not sure how is best to approach.
Example:
I have a sail. I want to know on what angle is the sail currently.
The sensor system must be waterproof and simple to add to an existing pole.
I myself thought maybe there is some sort of magnetic field sensor, add 2 magnets on both sides of poles and see the magnetic field somehow?
Because I know LEDs and other sensors are not best when wet and humid and such.
The Arduino will communicate with Raspberry (as I have extension ideas for it).
Does anyone have any ideas or experience, how should I approach this?
If needed, please do ask and I'll respond as best I can 
What angle range, precision of readout and accuracy do you require?
jremington:
What angle range, precision of readout and accuracy do you require?
I'd like per 1 degree angles. The pole is under 90 degree angel to the surface. But I'd like to sense the rotations and convert them to per 1 degrees, if possible. I would accept 1-10 degrees perhaps also.
are you talking about a sailboat ?
if that is the case, you could be needing an encoder on the boom.
Hi,
I think we need a diagram here to define what angle.
You have a mast and a boom and a sail.
Do you want
- angle of sail to mast with respect to long axis of yacht (horizontal)?
- angle of sail to boom with respect to mast (vertical)?
- angle of boom to mast with respect to long axis of yacht (horizontal)?
Thanks... Tom...
Hi,
I'm interested in view if it's looked from top-down perspective.
More specific, on the rotation, that the pole rotates around itself.
The boom does not matter that much for me. I'm more on interested, on how to add something on the sail pole and get the rotation reading (Without having to disassemble or add anything major to the boat itself).
I made quick schematic, sorry for poor quality
Interested on the rotation value (As specific as possible, but as always, margin of fault or such acceptable).
Any advice? Everything welcome
Hi,
So you want to measure the rotation of the mast, with respect to the deck?
What sort of boat has a mast that can rotate, the sail boats that I have been on all have masts that are fixed in the deck and cannot rotate.
Tom....
TomGeorge:
Hi,
So you want to measure the rotation of the mast, with respect to the deck?
What sort of boat has a mast that can rotate, the sail boats that I have been on all have masts that are fixed in the deck and cannot rotate.
Tom....
Hi,
I might be mixing some things up, but mainly was thinking about the smaller training sailboats. Those I kind of remembered having rotatable poles... but again, I might be wrong.
If it's not too much to ask, how would it be recommended to approach either case:
- Pole is rotating
- Pole is not rotating and boom only moves.
If boom is moving, then I believe the rotating part is just a bit higher than my first intention (If this explanation makes sense).
we are really only interested in the mechanical bits.
if you have a pole in a sleeve, then you can attach a sensor on one of those mechanical bits and a sensors or receiver or some such on the other bit.
we can help you figure out what sensor and how to mount.
can you link or show a picture of where you want to mount these parts ?
I am thinking that if you have a sleeve for the pole and there is a hold in the side of the sleeve so that you can paint the pole, you can paint lines and make an encoder with only paint. then use a couple sensors to see the paint and report position. [ see grey scale encoder ]
the other part you want, the human interface is only possible after you gather the data.
that display is not hard, once you have the data.
the only rotating mast sailing ship that was aware of was the Flettner Rotor ship made by Jacques Cousteau, the Alcyone...
but, the Alcyone was a turbosail, not a Flettner rotor.....
Ok, so I checked over. The pole has rotating area on the top part of the sailboat. They are rather small. One example would be: image
The sail comes out from the area.
I thought on making a color sensor or bar intensity reader. But again, water is my enemy and as far as I know, it's not reliable on this condition. As IR and others are not that reliable, if water gets on the laser glass.
I was recommended to try some magnetic form, but it's really not understandable for me.
My concern is not displaying the data, rather collecting it correctly right now, i.e. sensor for the mast to understand it's current rotation.
What model sailboat do you have?
Are you absolutely certain that the mast rotates freely?
Even if it does, why would knowing the angle be useful?
Edit: evidently on the Laser, the mast does rotate, and the boom with it. Looks like a pretty cheesy setup to me! http://www.laserperformance.global/product_images/pdf/Laser%20Rigging%20Guide.pdf
jremington:
What model sailboat do you have?
Are you absolutely certain that the mast rotates freely?
Even if it does, why would knowing the angle be useful?
Yes, I'm certain, as You did find out, it's quite cheesy.
I need rotation for later working for my own interest. Also, the same approach could be used in my other future project I have planned. They're quite similar setup on pole approach.
Or is there any specific part of interest in information, that might be needed?
It seems very unlikely that you will find a rotational sensor that will fit the mast, and also somehow be referenced to the boat deck. Use your ingenuity!
A very difficult problem will be to make everything completely waterproof. Dirty or salt water can destroy powered electronics on contact.
jremington:
It seems very unlikely that you will find a rotational sensor that will fit the mast, and also somehow be referenced to the boat deck. Use your ingenuity!
If put aside, that it's a boat and pole is removable (And water then), how would one solve the issue of getting the rotation angle of a pole?
assuming that the mast moves, you can make a device to strap around your mast and that could hold a gear with teeth.
a gear-tooth sensor is common use for a hall effect sensor.
you can put one so it would be dead center of a tooth, then one that is one third off, and a third that is one third off the other way.
on gear, three sensing points.
you can encapsulate the unit and use Velcro or some such to hold it to the deck.
you do not need to have an all metal gear, just the ends of the teeth so the hall sensors can see something.
A quadrature encoder needs only two sensors to detect both direction and relative rotation angle.
You could do that with gear teeth and Hall sensors as mentioned above, or a disk with holes and two optical sensors, one offset from the other.
Unfortunately the rotation angle is measured relative to however the encoder is fixed on power up, so you need some other way to detect the zero position, like a third optical sensor and a extra index hole in the disk.
jremington:
A quadrature encoder needs only two sensors to detect both direction and relative rotation angle.
You could do that with gear teeth and Hall sensors as mentioned above, or a disk with holes and two optical sensors, one offset from the other.
Unfortunately the rotation angle is measured relative to however the encoder is fixed on power up, so you need some other way to detect the zero position, like a third optical sensor and a extra index hole in the disk.
if the premise is a kit to add to a sailboat, and remove....
then a clamp around the mast would be in order.
not sure if the boat/mast does a full 360.
the reason the magnets would offer a good solution is that they will be immersed in water. any water blocking or altering the holes would cause errors in readings.
as for zero, a simple moving of the boom to a stowed position on the center line and a press of a button to zero would do it.
not sure of the best answer, but I think some testing would offer some results that could be interesting.
