Stepper motor to shake a line on a sailboat

Other Hardware Robotics
1

Hi, I have a problem with birds pooping on my sailboat. They gather on top of the mast and poop all over the boat. One way I get rid of them when I am there is I shake a spare halyard (a line running up to the top of the mast). This scares the birds away and they fly away instantly.

I want to design something that will shake the line periodically when I am not on the boat. I was thinking about using an Arduino, stepper motor and driver. I would attach the halyard to an arm connected to the stepper motor. Then program the Arduino to oscilate 180 degrees and back a few times every x minutes.

Does this idea seem feasible? Any potential issues? I have limited experience with stepper motors.

Thanks.

2

stepper motor is good for precise moving. in your case probably DC motor with eccentric weight can do the trick.

3

Power. Steppers are very inefficient.

4

quite feasible, a little bit of r and d..

could also try an mount an owl statue top of mast, should keep the other birds away..

good luck.. ~q

6

I thought of that but I've read that deterrents like owls, ect, only work for short periods of time. Eventually the birds learn it's static and ignore it. But I'll probably give that a try if my way overcomplicated method doesn't work, lol.

7

Thanks. That's probably a simpler solution. I wanted to use a stepper motor though so I could have it go 180, change directions, and go back 180 repeatedly. Would that be possible with a dc motor?

8

Thanks... not really a lot power needed though from what I can tell. Just basically need to move an arm back and forth with a line connected to it. The line wouldn't be under any kind of a load per se. Probably speed would be more important.

9

The problem with steppers is that the current draw is constant regardless of the load, and they are very slow compared to brushed DC motors.

To wiggle a line, the simplest approach is to connect it by a flexible coupling to the edge of a disk that is rotated by a brushed DC motor.

Image from classroom demo, but rotating disk could be vertical, rather than horizontal, and facing the string/rope.

1081×455 112 KB

10

every DC motor rotate 180° to right and there change direction to left and after 180° repeats.
i call it 360° rotation

11

Yes it's feasable.
I don't see any issues

12

May I recommend you take a look at waterproof hobby servo's?

They come in all sizes and strengths and standard with arms.
With the Arduino servo library it's very simple to operate them.

13

There's a commercial vineyard near me that uses hawk kites attached to a post to scare the birds away. They move around in the wind and are sort of realistic looking. They bring them out every year just before harvest so I guess it must work.

But if you're intent on using Arduino all you need is a DC gearmotor and a basic FET driver to control it. Program arduino to run for a few seconds every 5 minutes or something.

14

Sure - just have a switch of some sort to detect when it reaches 180 degrees (or whatever), then reverse.

15

If you have the mechanical wherewithal maybe something like an auto windshield wiper arrangement could work.  Motor only turns one direction and levers convert that into a back and forth motion.  I think with this you could dispense with the position switch(es), just run the motor for X seconds and let it stop where it is.