Week 4 Design Update

In order for our mechanism's gear to be fabricated, it needs to have a specific thickness of either 0.125" of 0.25". In SolidWorks the gear's thickness was adjusted from 0.5" to 0.25". To ensure that an appropriate amount of material was used, the gear, having a 4 inch diameter, was shelled to make the majority of the inside hollow. This gave the gear an appropriate volume of material, only 2.07 in.^3. Here is a picture of the final product, ready for fabrication.

Gear to be fabricated, with adjusted thickness and material volume.

The Arduino code was also updated so that the LCD screen displays "RELOAD" when the servo motor is in its initial position. In this position, rubber bands can be loaded onto the mechanism, so that they can be fired as the servo motor changes positions. The code was also adjusted so that after it is uploaded, the servo motor moves directly to its initial position. Here is the code:

And here is a video of the code in action:

Week 3 Progress Summary

During the week of November 18-22 team Rubber Band Gunner met on Wednesday, November 20, and Thursday, November 21. All team members were present at both meetings.

Before team meetings each member worked individually to brainstorm ideas for the overall mechanism. With the gear already designed, a base to hold the gear and servo motor, and an arm to launch the rubber bands needed to also be designed. Each member spent roughly one hour on individual work.

Wednesday meeting: Team Rubber Band Gunner met from 2pm to 4:30pm in Perry 321. During this meeting, the team finalized the design of our mechanism's gear, which is planned to be fabricated. The team also brought together individual designs and created all other parts of the mechanism on SolidWorks (listed in previous post). Some parts were used from grabcad.com, while others were created from scratch in SolidWorks (specified in previous post). The decision was made to attach the gear to a servo horn on the servo motor using adhesive, rather than cut a hole in the gear to fit on the servo motor. Also, the team decided to angle the top of the launching arm in order to avoid the rubber bands hitting the mechanism's arm as they launch. Finally, the team created an assembly in SolidWorks using all of the parts (displayed in previous post).

Thursday meeting: Team Rubber Band Gunner met from 4pm to 5:30pm in Perry 321. During this meeting, the team created a motion analysis of the assembly in SolidWorks that was created in the previous meeting. In the motion analysis, the servo motor rotates, causing the servo horn and gear to also rotate which would launch rubber bands over the launching arm, or prepare the mechanism to reload. The team also discussed intentions for next week.

For next week, the team plans to fabricate the gear that was created. Also, the team plans to update the mechanism's Arduino code, since the code for the mechanism has not been updated since week 2. The code is expected to allow the LCD screen to display "RELOAD" when the servo motor resets to its initial position.

Week 3 Design Update

During this week's meetings, the assembly of the entire rubber band gun was created in SolidWorks. The gear, base, and launching arm were all created as SolidWorks parts from scratch. We downloaded the servo motor, servo horn, and Arduino Uno board from grabcad.com.

 

Here are the pictures of the assembly, and each part used in the assembly:

 

Rubber Band Gun Assembly

 

 

Exploded View of Rubber Band Gun Assembly

 

 

Arduino Uno Board from grabcad.com

Base

Gear

 

Servo Horn from grabcad.com

 

Launching Arm

 

Servo Motor from grabcad.com

 

Video of assembly in motion:

 

Week 2 Progress Summary

During the week of November 11-15, team Rubber Band Gunner met on Wednesday, November 13 and Thursday, November 14. At both meetings, all team members were present. The team managed to complete a few important tasks at these team meetings, with the help of some independent work outside of the meetings from all team members.

First, the team finalized the basic design idea of a rubber band gun controlled by a servo motor (described in detail in previous post). The team also created a basic Arduino code to control the servo motor's position with a push button, as well as operate an LED and LCD screen (also described in detail in previous post). Along with these two tasks, the team began creation, on SolidWorks, of the gear belonging to the mechanism. The only thing currently missing from the gear's design is a center hole with proper dimensions, so that it can fit onto a servo motor.

For next week, the team plans to continue developing the entire mechanism in SolidWorks, starting with a center hole for the gear attached to the servo motor. The mechanism's design on SolidWorks will also include a rod to hold one end of the rubber bands, and a base to make sure that the entire mechanism is stable when performing its task.

Week 2 Design Update

We decided to create a gun that is capable of firing rubber bands using a gear and an opposite end to hold the rubber bands. Each rubber band is held between the gear and the opposite end, and as the gear rotates, the rubber bands are released. Multiple rubber bands can be loaded onto the gun due to the multiple ridges on the gear.

Here are some examples that we decided to base our idea off of.

Rubber band gun example 1
http://www.pirate4x4.com/forum/general-chit-chat/845049-show-me-your-rubber-band-guns.html

Rubber band gun Example 2
http://www.doobybrain.com/2008/03/08/classic-rubber-band-launcher-on-dealextreme/

We wired up the Arduino Uno board with a servo motor, push button, LCD screen, and LED. We made the preliminary code featured below, but we plan to edit it so that the LCD screen, and possibly the LED, perform more advanced tasks. The push button will cause the servo motor to slightly rotate, which will in turn, rotate the gear causing the release of a rubber band. So far, the LCD screen and LED have constant displays, only to indicate that the mechanism is working properly.

The the push button brings the servo motor through five different positions. The LED remains on and the LCD constantly displays "RBG" for Rubber Band Gunners. Here is a video of the current code in action:

First Meeting

Our group held our first meeting on Wednesday, 11/6; all three of our group members were present. At this time, we created this blog and finalized our project idea: we are going to construct a circuit using a servo motor to control a rubber band gun.