[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.


21 thoughts on “[Dino] Builds A Fetch-O-Matic For This Month’s Make

    1. 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!

    1. One thing I really like about Dino’s build is that it’s not over-engineered (if you can say so about a dog fetch machine :P). The machine shown in Dan’s video needs a controlling system, more bearings, more motors, more movable parts… Dino’s build is just pure ingenious, no electronic intelligence, all the intelligence is “hardcoded” on the build.

      1. > John says:
        >July 31, 2012 at 1:20 am

        >Don’t be ridiculous. A wiper motor can be gotten >at a junkyard or auto parts store for 10 or 20 >dollars.

        Not a chance – if you could then they wouldn’t be on ebay for 10 times that price would they? Did you look at the link?

        PS why can’t I reply directly to your comment? Anyone know?

  1. 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!!

    1. 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.

  2. 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.)

  3. Thanks, nice work Dino. Especially for us dummies. How about you make it, I’ll buy it, but keep it under $100.00 to beat the competition. Also, how about showing/sending me a link where I might buy one if they’re being mass produced already. Thanks Digger and Me.

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