[Dino] builds a Fetch-O-Matic for this month’s Make

Perennial Hackaday favorite [Dino] has an article in this months Make magazine. It’s an automated ball launcher that allows you to play fetch with your dog without wearing your arm out.

The powerhouse inside [Dino]‘s ball launcher is a windshield wiper motor powered by an 18 Volt cordless drill battery pack. When a ball in dropped into the hopper, it turns on a switch sending some power to the motor.

The swing arm that actually launches the ball is anchored to the frame of the ball launcher with a spring. This stores energy for one half of a rotation of the motor until the arm rotates half way around inside the box. Then, the arm quickly accelerates and launches the ball across the yard.

[Dino] says he’s working on training his dog to drop the ball into the chute after retrieving it, creating a perpetual game of fetch. At least until the battery runs down, that is. Video after the break.


  1. The Cageybee says:

    Shouldn’t it be a throw-o-matic or launch-o-matic?
    I mean, the machine isn’t doing the fetching.
    Or is the hack in getting the dog to fetch the ball?

  2. Nick says:

    See I need this for my dog, especially for when she gets in the pool, you tell her where to drop it and she will always drop it there unless you tell her otherwise

  3. Brian says:

    I can just imagine the dog gets the ball in the face when it gets shot out. Not that it’s something I want, but it could happen.

    • Dino says:

      It doesn’t have that much force. You can let it hit your hand and it doesn’t hurt. Sophie has been hit in the nose with it a few times and it doesn’t really phase her. In fact, she’s caught it point blank a few times after that!

  4. Dan says:

    Saw something similar a while back… this dog does put it back.

  5. Dino says:

    Jeri the sausage dog is the one that inspired me! Here’s my first attempt from several years ago.

  6. MakerDino says:

    I found this part originally at All Electronics for 20 bucks. Turns out they were a bulk surplus buy with limited supply. Make came up with the alternate source. HOWEVER, you can use any worm drive gear motor with a 1/2″ shaft diameter. Search around and adapt one to suit. Hack that shit!!

    • garym53 says:

      Not sure if this was a reply to my comment or not, but I am feeling a little justified in that you had access to a “special”. I would just like to reply to the second part in saying I literally have a “shed” load of (useful) “junk” and I wouldn’t have mechanically robust worm wheel in the lot – it may be a geographical anomaly but around my neck of the woods they are a) scarce, and b) bloody expensive. I do have, of course, loads of plastic worm wheels from old VCRs – not sure they would do the job though, hmmmm… I had also been thinking about using a flywheel.

      BTW I am not complaining about the video/project – just making a (I hope) pertinent observation.

  7. MakerDino says:
  8. Hirudinea says:

    Now all Sophie needs is an automatic feeder and a doggie door and she can get rid of Dino! :) (Wait, no, they haven’t invented an automatic pooper-scooper yet.)

  9. Daniel says:

    Does anyone know how the GoDogGo works? It seems pretty compact when compared to the other DIY builds I have seen.


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