Tennis Ball Launcher

thingiverse

I just make this huge cup with a long string attached that forms a slingshot for my dog's ball, her favorite thing to play with. Whenever she wants to play fetch she'll sit under it and wait until I pick up the hint. You can put this slingshot together using elastic strings and ropes wrapped around posts or trees, it takes just two or three items. For making this kind of rubber string I use this Amazon item http://smile.amazon.com/Thera-Band-Exercise-Dispenser-25-Feet-Special/dp/B00066D654/ref=sr_1_3?ie=UTF8&qid=1433641132&sr=8-3&keywords=theraband+tubing which is in medium strength and I always buy green. Anything stronger would launch the ball further, but needs more force to pull it back. After you wrap some elastic string with a series of holes, make a tie at both ends using these zip ties that keeps strings intact, then use strong ropes for forming an armature that will be wrapped around trees and any thing you see around. Another strong rope will connect your hand by threading its string through each of the same holes and finally attach it. If you are having trouble then watch this YouTube tutorial I found which made building my giant slingshot a whole lot simpler http://www.youtube.com/watch?v=3QL0OLnhLaI