Introduction: CannonBall Shooter

About: Just an ordinary person who loves #thinking and #tinkering

Flash project for #StayAtHome. The tablets and phones are glued to my kids' hands so I need to make a new toy to let the gadgets off -- although for only less than an hour >< and last for only a week or two. That means I need to think of new games regularly.

This time a CannonBall Shooter -- which is a catapult you can say. It had a codename BBShooter which stands for BasketBall Shooter, inspired from my previous projects namely Mechatronic Basketball Shooter and Catapult at the Office. It would take more time to design the basketball pole and ring, so I decided to use paper coffee cup as the ring. Later my sons use Lego figures as targets to hit and the name changes to "CannonBall Shooter".


  • A 3D printer.
  • Some filaments.
  • Approximately 2 hours time.

Step 1: Files

I use Creality Ender3 printer with these settings :

shooterV2.stl :

  • Support : NO
  • Speed : 50 mm/s
  • Infill : 20%
  • Build Plate Adhesion : Skirt

ball10mm.stl :

  • Support : NO
  • Speed : 25 mm/s
  • Infill : 20%
  • Build Plate Adhesion : Brim

The ball has radius of 10mm, not the diameter size. You can try a lower speed to let it dry better before the nozzle working on the next layer, especially at the beginning where the diameter of the ball is small and the nozzle will move to the next layer so quick therefore the melting filament at the tip of nozzle will also push the undried layer beneath.

You can also try using "support". It won't cost much filaments or time anyway.

Step 2: The Catapult

The catapult is printed all-in-one. Then you need to break-in the moving parts. The first part is the arm. Move it up and down and also left and right until it moves freely.

Do the same break-in to the lever but this one should be done carefully because the lever - from the middle to the right of catapult - is one piece and joined by a thin cylinder. You should do the break-in simultaneously to keep the lever one piece.

Step 3: Prepare Your Coffee Cup

Set a paper coffee cup (or anything) as the target and start shooting. Your pressure does matter to the flying speed and angle of the cannon ball, so is your aiming. To aim, you can hold with your left thumb pressing the catapult on the table and your left index fingers on the curvy wing.

Step 4: Next Level

For more challenging game mode you can try "hover mode". Hold the catapult in your hands hovering in the air, aim and shoot. This is more basketball than cannonball ^_^

Print more balls and use a net to hold them or use a wall so the ball will bounce back to you. You can also use marbles but they are heavy.

Step 5: Behind the Scene

Some of you may have noticed from the beginning when you see "shooterV2.stl". That means there must be V1 (version one) of this build. Yes, this pinky catapult is it. From the very beginning, I wanted to get variable angles in shooting. The V1 has moving lever for that reason. Taking the terms of car's steering wheel, I called it telescopic-lever somehow the "tilt" which is annoying. After testing few shots, I felt like "I do not need telescopic-lever to get various angles", then comes the V2.

Also there is minor mistake positioning the arm on the body which caused a lift on the body when the arm is at 90 degrees, which also caused the arm will not move forward if you give too much pressure on the front part of the body. The second mistake is the bucket too close to the pressing lever so I dropped the ball most of the time before pressing the lever.

Thanks to 3D printing I could fix it right away at the same day and brought the toys to my kids.