Centrifugal Airsoft Pen Machine Gun

Made almost exclusively from office supplies this centrifugal machine gun is the perfect device for booby trapping beloved objects that coworkers have a tendency to take.

So it's more of an air soft grenade in this form, however with a little more time you could without much trouble get it to shoot in the same general spot each time. I still think it's great fun to play with though, even with it's shoot everything in sight mode. In the future I would like to add a much larger hopper, but for now this suits my purposes.  It's hard to see in the video, but the round had a range of about 20- 25 feet.  They didn't hurt at any range... which is good.

Disclaimer: Don't hurt yourself, or others.  

Step 1 Materials & Tools

Materials

• 4x - large paper clips
• 2x - disposable ballpoint pens
• 1x - 9 volt battery
• 1x - small dc motor (the faster the better)
• 1x - paper
• 1x - magnet
• corrugated cardboard
• aluminum foil
• tape
• double sided tape
• air soft ammo or other small round object that will freely fit inside of the disposable pens.

Tools

• exacto knife
• needle nose pliers
• scissors
• awesomeness

Comments

[infernisdiem]

I just finished building one from an old rechargeable air mattress pump, and reusing some of the shell it came out looking nice. I loaded it up in a box and tapped the wires together, and in that split second, it emptied the hopper. I used a 3rd pen cartage to hold the center wire up and model glue to fuse the hopper to the barrel, and the guard to the shell. Now to make a dead-man switch muh wah ha ha ha

[pastprimitive]

I like it! I hope it defends you well.

[infernisdiem]

I apparently set something on top of mine, making the hopper jiggle, so I put a little more model glue to hold it into place, and being the inpatient person that I am, I started it up, and ended up with "cobwebs" shooting from it. something that I am going to have to try for halloween affects :D

[infernisdiem]

I'm going to tinker with it, i I remember correctly, mythbusters made something like this, and had it so that it would shoot out of one spot... now to just drink aa 2l of soda to harvest it's bottle

[Nicapizza]

Hey, could you a few more pics on this step?

[infernisdiem]

I made a hole just behind where the balls were to feed in, and it works just fine for me.

[nshaikh]

hey its good but you need more clear pics and more details because i cant figure out how it launches the balls....

[rjhw1]

Sorry, i might sound a bit snotty here, but it seems my physics lessons have finally come in handy. Centrifugal force is not real, you may be referring to centripetal force, is the force that's causing the pellets to shoot out of the pen. The pellets want to move in a constant speed straight line, but the barrel of your pen is pushing against the pellet while it stays in place when the pen rotates, causing the pellet to fly out of the pen. Just like those amusement park rides where the ride spins around really fast, no force is pushing you out, its just the force of the wall behind you that is constantly pushing you in a circular direction, your actually accelerating toward the center of the circle. This is referred to from newtons first law, objects in motion or rest want to stay in motion or stay at rest unless acted upon by an outside force. Yay physics!

[pastprimitive]

Umm... Not to be snooty either. Yes you are right, technically speaking centrifugal force is a fictitious force. However it is very common to use the term centrifugal force when describing forces applied on an object from it's frame of reference.

Or in other words theoretically speaking the air soft projectile from it's frame of reference is experiencing a centrifugal force, or a force causing it to move away from the axis of rotation of the machine gun motor. Centripetal forces are used to describe forces pulling an object towards the center of rotation.

I appreciate the physics theory here. But it has become quite standard to reference centrifugal force in different mechanical systems that utilize rotational forces to fling an object outwards. For example a centrifuge is a device that references centrifugal force in the name, or describing how the system works.

Here's an example of another machine gun invented quite some time ago that references centrifugal force.

Regardless of how fictitious centrifugal force is in physics theory, according to laymen's terms it exists enough to be a common way to reference mechanical systems that utilize rotational forces to fling object outwards. The centrifugal machine gun is intended to fling projectiles outwards, not pull them inwards. Otherwise I would name it a centripetal machine gun. But thanks for being thorough.

[lookwhatjoeysmaking]

relly coll but need beter pictures when you add the moter becouse i cant figure out how it lunches the pellets

[Nicapizza]

SWEET!!! Cant wait to build it!!