A while back, [Dino] built an automatic ball launcher for his dogs, but he wanted to revise it to make it smaller and a bit more user-friendly. While watching an episode of “Prototype This”, he came across a great idea to improve his launcher, so off to the workshop he went.
He repurposed a power window motor from a car, and mounted it to some wood-reinforced aluminum sheeting in his garage. He added a piece of aluminum tubing to serve as a spring-loaded launch arm, which is drawn back by a small lever attached to the window motor.
When a ball is dropped onto a switch at the bottom of the launcher, the window motor starts turning, which pulls the launch arm back into place. Once the arm reaches the tipping point, the spring snaps it forward, launching the ball across the yard. The lever attached to the window motor eventually makes its way back under the launch arm, and is stopped by a switch that is also attached to the motor.
After the prototype was finished, he added some more wood to protect the mechanism from his dogs and vice versa. A hopper was added to the top of the structure to allow the dogs to load the launcher themselves, after a bit of training.
Now, some of you might wonder what is wrong with [Dino’s] arm. Truth be told, it works just fine. If you are a frequent Hack-a-Day visitor, you know that he spends plenty of time in the workshop, so this is an easy way to let the dogs entertain themselves until their owner is ready to play.
Check out the video embedded below for a demonstration of the launcher, as well as a detailed walkthrough of how the mechanism works.
[youtube=http://www.youtube.com/watch?v=IgyK0C_oHPI&w=470]
I love springs, there are too few of them in hacks..
The 2nd part of the video was amusing and full of suspense.. :-)
Ah the things that could be launched with that :-D
Nice project, simple robust design.
I think the ‘hopper’ is too high for the dogs too drop the ball easily.
I think the chute just needs to be shorter so it isn’t as hard for the dog to get the ball over it, otherwise an amazingly simple project
Cool idea, just to save everyone the dissapointment:
SPOILER
the dog doesn’t figure it out in the end
/SPOILER
I think a chain with a freewheel clutch would allow for harder kicks so you are not fighting a worm gear …
I’m sure we have all seen the other ball launcher on youtube from years ago. According to the writeup, the dachshund that it was built for used it a grand total of 2 or 3 times when no humans were around. Unlike this dog, he had the ball-loading precedure *down*. In fact, when it failed to launch, the dog even picked the ball up and reloaded it. http://www.youtube.com/watch?v=4PcL6-mjRNk
“…is read to play.”?
More coffee please :)!
The dog did figure it out, just couldn’t get its mouth open wide enough to let go while having its head over that rim. If the rim was a bit lower, it might got it.
If only the dog figured that out… I guess the dog would then enter an endless loop…
Also to fix the height issue couldn’t he have the kicker rotate about a vertical axis rather then a horizontal one?
@Necromant
I had a lab that used to take a ball to the top of the steps and put it by the edge. Then she would lay down and slowly nudge the ball tell it started to fall. When it hit the second step she would chase after it and repeat.
She eventually fell asleep at the top of the steps with the ball touching her nose!
I’ve lowered the height of the hopper and she got the ball in there a few times last evening. She’s smart… she’ll eventually figure it out. :) I’ll post another video when she does.
@ Drake, that is a GREAT idea! AND, when the arm gets past center, it whips around freely. It’s not directly coupled to the worm gear.
@ Boku, now you’ve got my wheels turning. Old cell phones, Barbie dolls, Apple products… lol
Very cool!
Use a three-sided hopper on the side after adding a hole to the plywood. Ball will end up in the same place and without the bounce.
@Drake, the worm gear only moves one piece of it, the arm is free to kick the ball when it passes the halfway points. watch the video and notice the limit switch which resets the launcher portion. The kicking force is determined by the spring, not the motor.
I love this. Agree about the chute/funnel height being to tall. He could get rid of the bouncing problem by making it a side loader instead of a top loader. That way, you only need 3-6 inches of fall from the drop to the switch for it to get there. That would also get the dog to the side instead of the front where the ball exits.
@JamieWho
Didn’t catch the pivot the first time I watched the vid!
What happens when the dog learns to drop the cat in the hopper?
@ Kieth & JamieWho … another good idea. I think I’ll try that and yes it would keep her to the side upon loading.
This is the kind of feedback that I love when I post a project! I almost always make a few mods based on community input so thanks for your comments! :)
A bit late to the party here, but back in high school our FIRST robotics team built a 8″ ball launcher based off the same throwing concept. We used a one way roller bearing as we were continuously firing to catch the arm in the maximum position it slung to after release of the ball.
http://marsbot.org/files/shooting.wmv
Anyways, really like what you’ve made here, very clean and clever and gave me a bit of a throwback :). Thanks for sharing!
First time EVER my grilfriend new a project before I did!
she is a dog person i am the geek, this was featured on a dutch dog forum before.
Wondering if you could elaborate on the spring type and positioning. My son built a launcher using your design. All worked perfectly (he substituted a large plastic funnel for the hopper and inserted rails on the ramp to cause the ball to better trigger the launcher switch). He could not, however, get much kick out of the arm. The spring he used would either bind the window motor if stretched too tight or simply roll the ball out of the launcher if relaxed. How did you achieve your results.
Can you make a video that is a step by step build for this???
easiest workaround for the hopper being to high… mount it on the side. bonus of having it on the side the dog is never in the way of the launched ball. wanna built one of these for my friends overactive dachhund.
I would favor the hopper being at the dog’s nose level or lower (your dog really can’t simply drop it; she needs to hoist it over, which is unnatural for a dog), and off to the side with a right-angled ramp in to get the dog and eyes out of the way of the outbound ball trajectory. Ramp off to the side also could give more stability to the base.