User:Kjaved373/enes100/rubberband gun

Link to project 550_JHK team page.

Give instructor top 3 project choice list

 * 1. Rubberband gun


 * 2. Rube Goldberg


 * 3. StrandBeest

Write problem statement
What should the design of a rubberband gun be for efficient reloading and firing?

Assign Task1
Research different models of rubberband guns.

Look for easy ways to reload.

Look for models that have high capacities.

Compare actual work done to Task1
Made an early prototype of a model rubberband gun that has a trigger and can shoot two rubberbands at this time.

Week1 Narrative
My teammates had already made a base for the rubberband gun and I expanded on it by adding a release and a trigger. I had trouble at first trying to find a way to release the rubberband efficiently without sacrificing reloading time. The wheel Lego pieces seemed like a good starting point to release the rubberbands, but that turned out to be to weak. There was another piece that connected to the gun to form a 45 degree triangle and that released the rubberbands excellently. The problem was finding a trigger. I tried three ways to use a trigger and the one that worked was putting an "L" shaped piece underneath to prevent from automatically firing. When you want to fire, you just pull that piece and it shoots very efficiently.

Assign Task2

 * Expand on prototypes built
 * Research better triggers and ways to release rubber bands

Compare actual work done to Task2
Improved on the pistol and crossbow designs to allow each to fire multiple rubberbands and a better base to hold it. In addition, another prototype of a rubberband gun was made.

Week2 Narrative
The beginning of the week was spent on looking for ways to allow the rubberband guns to fire more than one rubberband. This was done by adding another trigger and a few more release points. The prototype of a new gun was made using spare lego pieces found at home. The trigger system is differnet than the previous guns and only allows one rubberband to be fire at this time. It is similar to a bow and arrow but it shoot the rubber band by pulling back a piece of the gun and letting go.

[| Video of Crossbow firing 5 rubberbands]

[| Video of the prototype gun firing a rubberband]

Assign Task3

 * Get ready to present to class
 * Improve on the prototype design
 * Improve accuracy and efficiency of the rubberband guns

Week3 Activities
Presented to class all the different designs of rubber band guns made so far, improved on the two prototypes and increased the strength of the pistol. Also, made a sketch of new proposed way to automatically fire rubberbands.

Week3 Narrative
The first half of the week was spent on putting together a presentation for comparing the trigger systems and comparing the advantages and disadvantages of each. The pistol rubberband gun was made more powerful and accurate by lengthening the base to allow the rubber bands to stretch further. A sketch was made that allows the rubberband gun to fire rubberbands automatically by a rod going back and forth (similar to a seesaw) and shooting a rubberband each time it switches sides.

Assign Task4

 * Improve on the sketches made by all the team members
 * Start building the newly proposed trigger systems and guns
 * Finalize the existing rubberband guns to make them look more aesthetically appealing

Compare actual work done to Task4

 * The guns were made more appealing by minimizing the number of pieces on the guns while maintaining durability
 * The extra pieces went to adding on to the "geared gun" and adding a handle to the other guns
 * Tested the power of each of the guns by taking measurements of how far each fire goes

Week4 Narrative

 * The pistol was greatly stripped down to make it even lighter and easier to hold.
 * The crossbow was also stripped of some pieces, but some pieces were added to make it more durable.
 * The rifle was improved upon hugely by adding a gear that allows the rubber band to be wound up, and made stronger.


 * There was a test done to test the power of each gun, the following are the results:

- Each gun was loaded twice with similar rubber bands and fired straight from the same starting point.

- The distance was measured each time to determine the power of each gun.