Hi all!
Following recommendations from this forum, got a windshield wipers motor to move the steering wheel of the boat. On the wheel itself, there is a belt from previous autopilot (it was Navico WP4000, see pictures attached).
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I would like to have the wheel moved by a windshield wipers motor, to which I added a 3D printed wheel to move the belt (see pictures #3 and 4, attached).
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Question is: how to provide tension for the motor, when the autopilot (Pypilot) is engaged, and ease off the tension, when I switch to manual? In other words, when the autopilot is on, the tension in the belt that moves the wheel should be high, but when I switch to manual control, the belt that moves the wheel should be relaxed.
Any engineering ideas?
Thanks,
Gennady
It's usual to have some sort of cam arrangement controlled by a lever. Operating the cam shifts the distance between the pulleys, which causes the belt to engage.
This install is, I think, similar to what you have.
https://www.cruisersforum.com/forums/f12...ost2394376
(2022-11-28, 02:00 AM)CapnKernel Wrote: [ -> ]It's usual to have some sort of cam arrangement controlled by a lever. Operating the cam shifts the distance between the pulleys, which causes the belt to engage.
This install is, I think, similar to what you have.
https://www.cruisersforum.com/forums/f12...ost2394376
CapnKernel, thank you for a prompt reply. The question then becomes: where can one buy such a cam with a lever? Or how to make it?
the teeth on the belt do not seem to match the teeth on the wheels. This is known to slip with weather helm.
As for tension. Can the motor be mounted on a bolt so that it can swing like a hinge to tension the belt?
(2022-11-30, 03:29 PM)seandepagnier Wrote: [ -> ]the teeth on the belt do not seem to match the teeth on the wheels. This is known to slip with weather helm.
As for tension. Can the motor be mounted on a bolt so that it can swing like a hinge to tension the belt?
Hi Sean,
Thanks for comment.
You're probably right. The teeth on the belt do not match teeth on the wheels. But the teeth still provide friction, that with proper tension should rotate the wheel. I hope so. We will see in practice if that is correct.
As for tension, I have ordered this stand for computer monitor from Amazon:
https://www.amazon.com/VIVO-Adjustable-A...=8-61&th=1
It has the advantage of easily going up and down, with one bolt release.
And I am now designing the casing for the motor. First draft can be seen 3D printed in this video:
https://www.youtube.com/watch?v=PVdKkKlW1k8&t=13s
Hope to hear your feedback. And hope things are going well for you,
Gennady
I know people who used those teeth with that belt and it slips with any amount of weather helm. It works in some conditions though.
It will depend on your boat and rudder but in any case you will find out. I managed to 3d print the larger pulley with the correct teeth but my printer was slightly incorrect 0.5mm wider over a 180mm wide circle which made the teeth slip on one tooth out of 120. I need to calibrate the obliquity in the printer (delta style) to properly print pulleys with more than 100 teeth and got sidetracked.
I can post my 3d files for pulleys if you like, modified from thingiverse ones I found. In any case. the wiper motors are generally reasonably waterproof to begin with but additional protection is a great idea. It looks good.
(2022-12-01, 12:49 AM)seandepagnier Wrote: [ -> ]I know people who used those teeth with that belt and it slips with any amount of weather helm. It works in some conditions though.
It will depend on your boat and rudder but in any case you will find out. I managed to 3d print the larger pulley with the correct teeth but my printer was slightly incorrect 0.5mm wider over a 180mm wide circle which made the teeth slip on one tooth out of 120. I need to calibrate the obliquity in the printer (delta style) to properly print pulleys with more than 100 teeth and got sidetracked.
I can post my 3d files for pulleys if you like, modified from thingiverse ones I found. In any case. the wiper motors are generally reasonably waterproof to begin with but additional protection is a great idea. It looks good.
Hi Sean!
Thanks for reply. Yes, please post your 3D files, but I use Fusion 360, and hence not sure I will be able to see your files. In case it is STL files, then it is a different story.
In case idea with the belt and windshield wipers motor doesn't work, what would you recommend? Maybe another kind of motor?
Thanks for reply,
Gennady
You might find looking at CPT autopilots for a commercial version of the windshield wiper motor mechanism for inspiration.
http://cptautopilot.com/
I just am ordering that and try it out.. if I ended wishing I had wind vane mode or other networked modes, will replace their control system with pypilot
(2022-12-01, 01:09 AM)Gennady Wrote: [ -> ] (2022-12-01, 12:49 AM)seandepagnier Wrote: [ -> ]I know people who used those teeth with that belt and it slips with any amount of weather helm. It works in some conditions though.
It will depend on your boat and rudder but in any case you will find out. I managed to 3d print the larger pulley with the correct teeth but my printer was slightly incorrect 0.5mm wider over a 180mm wide circle which made the teeth slip on one tooth out of 120. I need to calibrate the obliquity in the printer (delta style) to properly print pulleys with more than 100 teeth and got sidetracked.
I can post my 3d files for pulleys if you like, modified from thingiverse ones I found. In any case. the wiper motors are generally reasonably waterproof to begin with but additional protection is a great idea. It looks good.
Hi Sean!
Thanks for reply. Yes, please post your 3D files, but I use Fusion 360, and hence not sure I will be able to see your files. In case it is STL files, then it is a different story.
In case idea with the belt and windshield wipers motor doesn't work, what would you recommend? Maybe another kind of motor?
Thanks for reply,
Gennady
I use openscad. Not sure about fusion 360 but I put an stl file. The issue is you cannot easily edit it.
The belt and wiper motor should be good, I just suggest toothed pulleys that match the belt teeth.
https://drive.google.com/drive/folders/1...sp=sharing