# Question Servo motor

Hi all,
since a few weeks I learned about Arduino and since that I love it!!
I bought the starters kit and now I have a project in mind that I can use for training with my dogs.

A part of this project is a ball supplier. I have a reservoir of balls, but the the supplier should only provide 1 ball at a time.
I’ve added a simple drawing to illustrate this.

I want the axis to rotate full circles, but with a particular degree at a time.
I’ve read that a servo motor can be used to rotate particular degrees, but that this is limited to 180°.
Are there any other motors that I can use?

And I have another question concerning the servo. Can the speed of a servo be manipulated?
I want the delay of the ball when on the supplier as small as possible. It should provide the ball as quick as possible.

Thanks

A servo would only work for that application if it could reverse back to collect the next ball. If that is feasible then a servo would be good because they are cheap and very easy to work with both mechanically and using the Arduino for control. Look at the servo sweek example that comes with the Arduino IDE to see how to control the speed.

You can get sail winch servos that can rotate about 3 revolutions with position control. But then it would have to reverse back to the start.

There are also continuous rotation servos but with them the Arduino can control the speed and direction, but not the position. You would need some other device - perhaps an optical sensor to tell the Arduino to stop the servo at the right position.

You could also use a stepper motor which can rotate continuously while the Arduino keeps track of its position. You also need a stepper motor driver board between the motor and the Arduino so they are more expensive and the Arduino code will be a bit more complicated.

My suggestion would be to try to find an arrangement where the back and forth movement of a standard servo would do the job. Imagine a disk with a slot for one ball. The slot faces the container and a ball falls in. The disk rotates to the exit chute and the ball falls out. The disk reverses direction to pick up a new ball.

...R

I want the axis to rotate full circles, but with a particular degree at a time.

Perhaps you should use a different type of ball feed. To use a servo, you could have the servo lift a ball entry gate while lowering the exit gate to load a ball, then lift the exit gate while lowering the entry gate to release the ball.

Hi guys,

Thanks for the feedback. Based on that, I had some thoughts and I will change the design of the supplier to one that only needs to rotate less than 180 °.
That design will also satisfy my requirements, and I can use a servo.

Thanks!

Stevy: I will change the design of the supplier to one that only needs to rotate less than 180 °.

Have fun!

...R