making a ping pong ball launcher Pt. 1
Alternate titles: "How to Choose a Ping Pong Ball Launcher Prototype," "How to UPGRADE a Nerf Gun."
Yes, you read that title right. But how did we end up here; creating (albeit, a VERY early prototype) a ping pong launcher out of a nerf gun, random parts and raw determination? It all started with my second assignment brief: "Create a ping pong ball launcher for your obstacle course." While I wasn't able to work on the buggy (I didn't have it as of writing this), it seemed like a project to keep me busy. The ping pong ball launcher will be used as a main component for the obstacle course, so I needed to have a working prototype before the buggy arrived.
"But why a nerf gun?" you may ask. Well, I'm getting to that silly (don't be impatient). I first started with three potential design ideas:
Deflated balloon launcher
Upscaled Nerf gun
1) Deflated Balloon Launcher
The first idea involves the use of a "cup" and a deflated balloon held in place with a rubber band. The ping pong ball goes into the cup, then you pull the balloon back. When released, it launches the ball out. While it is a simple design, incorporating a ball holder, or a way to fix the launcher in position could prove to be difficult. Additionally, the power applied to the launch may be inconsistent as it is impossible to pull the balloon back the same amount each time by hand.
2) Upscaled Nerf Gun
This idea involves upscaling a Nerf gun body into a ping pong ball launcher. Most Nerf guns (or, any dart gun) uses a chamber of fixed air that is pushed by a spring mechanism. The force generated by this causes the dart to launch. Ideally, I would upgrade an old Nerf gun so that it can hold ping pong balls, as well as launch them with the same power. The main downside is that the launcher's power would be limited to the amount of air that can be held.
3) Ping Pong Mangonel
Finally, my last idea features the Mighty Mangonel, a medieval classic. This idea was mainly inspired by a first-year project that involved a mangonel. The mechanism of launching is straight forward, utilising a spring to convert potential energy into kinetic energy. While it is the coolest looking idea (in my opinion), it has the potential to be the most expensive idea since I don't have parts that could be upscaled. Furthermore, it could be difficult to include an "auto-loader" for the ping pong balls, which is a key feature I want for my final design.
Final Choice? Ping Pong Nerf Gun!
After many considerations, I decided to go ahead with the Nerf gun idea. I have many different Nerf guns lying about at home, so it would only make sense to use them. To start, I decided to use the Nerf "Disruptor" as the base of my launcher. It is a well built Nerf gun and is known for being very easy to modify.
Looking inside the Nerf gun we can see the air chamber, spring loader, and trigger. The mechanism for the magazine can be ignored since I need to create a new one for the ping pong balls.
While I still need to come up with a bill of materials for the launcher, a useful upgrade that can be done is to remove the air restrictors from the air chamber. Using some thin pliers, I removed the cross-section that restricts the airflow during operation. While this makes the darts hurt more, it an easy way to ensure the max amount of force is used to launch the balls.
Additionally, I lubed the sides of the wall and spring mechanism using silicon grease. Reducing the amount of friction allows for a more uniform transfer of energy.
These two upgrades provide more force to come out of the chamber. Comparing with my other Nerf guns, the darts now shoot further and harder. Hopefully, this smoothly translates into being able to launch a ping pong ball from a respectable range. As for the launcher itself, I plan to cut the front half off of the gun to make room for a new magazine (as you can see below).
The magazine for the balls will be made from PVC pipe and a wood base. The base to change the gun's angle will also be made of wood. While there are more aspects that I need to finalise (e.g. how to rotate the new magazine), the upgrades and CAD I have created should hopefully provide a solid foundation.
I hope you enjoyed that update of my ping pong ball launcher. In the coming days, I will be working on my first prototype so look forward to that. Also, my next IGTV will be out either by tomorrow, or the day after! So look forward to that! P.S don't forget to follow my Instagram! As always, stay safe and healthy, and I hope to see you again soon!
BTW, I updated the CAD for my buggy. Take a look!