Hall Effect Rudder Position Sensor

[SVHM]

Sean is selling a rudder position hall sensor.  The wiki says that a potentiometer is required.   I assume that the hall sensor output is a variable voltage that is similar to a potentiometer and that it can be recognized by Pypilot.  However,  my implementation will require a much smaller sensor than Sean's.  

I would like to know what types of hall sensor will work with Pypilot?   What are the specs I should look for?

[seandepagnier]

The motor controller takes a voltage for rudder position. The hall sensor used is mlx90316 however there are a lot of alternatives that would work.


What do you mean you need a smaller sensor? Could you explain a bit better?

[SVHM]

I have made my own windvane and I intend to drive the vane head with a linear drive motor. The vane head drives a trim tab, which turns the oar. The rudder position sensor will be used to indicate trim tab position, not the position of the oar angle. Because I am using the trim tab I run the risk of overpowering the oar and stalling it. The linear drive has built in limit switches but the vane head turns on an axis. I would like to mount the rotary position sensor directly on the vane pivot rod along with the linear actuator in a small box. The control lever is too small to use a sensor that is used for a real actuator.

I am hoping to be able to control the rotation of the oar with rudder angle settings.

I would like to use something akin to this but with a hall sensor.

https://www.digikey.com/en/products/deta...gKfUfD_BwE

I intend to share the setup here when it is finished.

[seandepagnier]

overpowering the oar? I am not sure I understand. If the trim tab is at max deflection that is it right?

If I understand correctly, you have a trim tab on a pendulum oar and the oar drives the main rudder?

Keep in mind doing this will require very little power, but will also have the most lag or delay in reaction to driving the main rudder so will limit the ability to hold a straight course. If you could rotate the oar directly it might help, and/or consider driving the main rudder with a linear sensor in light wind as this doesnt use much power and will give better results, then switch to the windvane in stronger conditions.

anyway.. the rudder feedback sensor I have designed can measure angle to 0.1 degrees, so even if the linkage only moved the sensor by say 5 degrees, it would still give somewhat adequate resolution.

In any case, please post your setup and results as much as you can!

[SVHM]

If you think of a how the Hydrovane works, it's an auxiliary rudder type vane. That's what I have made. The Hydrovane uses gears, mine uses a trim tab, like the old Navik vane. The trim tab is on the aft end of the oar, just like an aircraft aileron. The response of the oar twist is directly proportional to the deflection of the tab. The oar moves immediately. The boat movement, is probably slower. Since it is not a servo-pendulum, it doesn't turn the boat rudder and I expect it to be slower. That's why I want to control tab deflection precisely. If the oar moves and the boat doesn't, the controller could try to over compensate.

I looked at the datasheet for the mlx90316 and it is the IC with many configurations. Your wiki says I need a 3 wire sensor. I didn't see any in there. I was hoping for a standard 3 wire setup that I can just hook up to the controller and done.

[seandepagnier]

If you think of a how the Hydrovane works, it's an auxiliary rudder type vane. That's what I have made.  The Hydrovane uses gears, mine uses a trim tab, like the old Navik vane.  The trim tab is on the aft end of the oar, just like an aircraft aileron.  The response of the oar twist is directly proportional to the deflection of the tab.  The oar moves immediately. The boat movement, is probably slower.  Since it is not a servo-pendulum, it doesn't turn the boat rudder and I expect it to be slower. That's why I want to control tab deflection precisely.  If the oar moves and the boat doesn't,  the controller could try to over compensate.

I looked at the datasheet for the mlx90316 and it is the IC with many configurations.  Your wiki says I need a 3 wire sensor.  I didn't  see any in there.  I was hoping for a standard 3 wire setup that I can just hook up to the controller and done.

Nothing is "immediate"

Ok so you are using auxillary rudder.   I understand, what it comes down to then is, the trim tab arrangement will reduce some steering power from the steering oar compared to rotating the oar directly but greatly reduce the amount of power needed to turn the oar.     If the oar were well balanced I would suggest just somehow driving the oar directly, but in any case it is all up to you.

The pendulum style is popular because when the boat slews sideways, the force on the pendulum oar automatically corrects this motion, so they work well in big waves.   In flat water there is no advantage and they are more complex.


In any case,  the mlx90316-200 is the 3 wire version you would be looking for.    It has 8 pins, but only 3 are used in that version.    There are other versions.    My rudder feedback sensor uses this chip, and runs the 3 pins used into a 3 wire cable.