Trying to build a dog ball thrower

Hey,
So my friend and I at work thought about creating a simple ball thrower for my friend dog. He always brings his dog to work, and he wanted me to print him something, and that is what we had in mind. Of course, I wanted to print this

But the friend said that his dog doesn't like being dressed with props, so we skipped that :)
Let's look at the designs I tired:

The concept with the above design is that the center cylinder will spin really fast and will throw the ball. I used a really small 3.3v motor, which was way overheating and underpowered for this job and did not manage to get the job done.
After looking at some other designed I saw that the motors are much, much more powerful than what I had. In order to keep exterminating, I wanted to check how my drill (which is really powerful) would handle this job. I create this tool (which I can insert into my drill) throw the ball and see what happens.

Long story short, It broke:

 But I learn a lot of things from this experiment. For example, it seems that the teeth are way too long, and we have very few of them. I experimented more with this idea:

It was not great as it is, and would probably require some good enclosure in order for the ball to not throw in any direction. I continue to play with more ideas:

As you can see, you would need a really powerful motor or gear. I tried to see what Thingiverse has in the gears department and found this really cool stackable gears, I printed one to just to have fun with it:

At this point, I realized this project is going to be long or expensive, and we might want to create something more simple. The friend and me thought about making a food dispenser. I designed something like this:

It was semi-working. The design is similar to a gun, and similar to a gun it could jam, instead if you had different kinds of "bullets". At this point the friend bought an already built machine instead of waiting for me :( so that's all I have.. might want to continue this project in the future :)