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PAR 6

Team: C1-01

EF 151: Section C1

Presented: April 28, 2010

Created By: Austin Henrikson

Brandon Sanders

Bruce Shelander

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Abstract:

Group C1-01 designed the PAR 6 Rube Goldberg device. The PAR 6 utilizes collision, torque, impending motion and center of mass in order to activate an electronic device (a calculator) and trigger any subsequent devices which may be sequenced after the PAR 6 by means of a toy helicopter. The Par 6 device was constructed for less than twenty dollars and functions with 95% reliability, factoring human error and environmental variables. Several difficulties were overcome during the design and construction of the PAR 6, and recommendations for improvement include attaching a pitch system to the base of the device in order to compensate for environmental variations, reinforcing the connection between the control string and mousetrap, and formulating a better method for controlling the flight path of the helicopter. Group C1-01 feels that these changes would effectively increase the reliability of the PAR 6 device with minimal cost increase.

Introduction:

Group C1-01 was tasked with the responsibility of creating a Rube Goldberg device which would utilize at least five steps, four of which would exemplify major concepts learned throughout the EF151 course; and which would result in the activation of an electronic device. The following information presented within this report will describe the design process, a description of the device itself (including a bill of materials), the observed results of device testing, and a summary of observations and conclusions reached throughout the assigned task.

Design Process:

In the planning phase of our design, group C1-01 first considered the constraints placed upon the project by the instructors. The major restrictions which were dictated are as follows:

When started, device must fit within a 0.5m x 0.5m x 0.8 m box. The device may go outside these limits during its operation.

Have up to 1 minute to set up device. The device must have at least 5 different steps. Device must operate without interaction once started. From start to finish, the operating time of device must not exceed 2 minutes. Device must include examples of at least 4 out of the following concepts:

o Projectile motion o Conservation of translational energy o Conservation of rotational energyo Conservation of linear momentum (collision)

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o Conservation of angular momentum o Torque (rotational motion) o Center of mass (balancing an object) o Etc.

Team is limited to a budget of $20. The device must be able to be operated in a safe, clean, and non-destructive manner in

Estabrook 111 (e.g. no fires, explosions, sharp projectiles, high-speed projectiles, etc.).

With these factors in mind, group C1-01 decided to utilize collision, torque, impending motion and center of mass as our four major concepts. These concepts were chosen after also considering projectile motion, conservation of translational energy and conservation of angular momentum. Once the major concepts were determined, group C1-01 evaluated available resources (most of which were salvaged from Estabrook 13), expense restrictions, and time constraints in order to determine which materials and processes would be utilized to construct the PAR 6 device. Finally, group C1-01 set about drawing blueprints and schematics for the PAR 6 device, which would be continuously altered and adapted in order to adapt for real world factors until the final device was completed.

Device Description/Bill of Materials:

The PAR 6 device consists of steps, four major concepts, and is designed to work both independently and in sequence with other Rube Goldberg devices. The PAR 6 is a Rube Goldberg device with a mini golf theme which is designed to activate an electronic device (a calculator) and trigger another device in sequence by means of a toy helicopter.

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The first step to occur, which is also the first major concept utilized, in the PAR 6 device was a series of six collisions. This step demonstrated conservation of linear momentum six times. The required calculations to prove this conservation may be viewed in Appendix A.

The second step to occur in the PAR 6 device was a zip line which transported the golf ball from the first step dwon to the second section of track towards the wheel.

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The third step to occur , which is also the second major concept utilized, in the PAR 6 device was a wheel which transported the golf ball from the first two steps down to the fourth step. This wheel demonstrated torque. The required calculations to prove this rotational motion may be viewed in Appendix A.

The fourth step to occur , which is also the third major concept utilized, in the PAR 6 device was a series of three levers which activates the fifth step. This series of levers demonstrated center of mass. The required calculations to show the center of mass may be viewed in Appendix A.

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The fifth step to occur , which is also the fourth major concept utilized, in the PAR 6 device was a balance beam system with a second golf ball placed on top which turns on the electronic device (a calculator). This system demonstrated impending motion. The required calculations to prove the impending motion may be viewed in Appendix A.

The sixth step to occur in the PAR 6 device involved the first ball rolling down the final stretch of track in order to fall into its hole and trigger the controls to the toy helicopter which triggered the next device in sequence.

Assumptions made concerning the calculations for the four major concepts are as follows:

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The golf ball which falls into the cup on the wheel is considered a point mass. The magnetic attraction in the second step is considered to be negligible. Wedges used in step five are considered to be of the same length and mass. Forces of friction throughout the entire PAR 6 device are considered negligible.

The following is a comprehensive listing of materials utilized in the construction of the PAR 6 device and an estimation of costs of the aforementioned materials:

Bill of Materials:

MaterialQuantit

yEstimated

CostPlywood (2'X2'X0.5") 2 $3.00 Nails (2.5") 20 $1.00 Screws (1") 6 $0.30 Eye Hooks 2 $0.20 Magnets 2 $2.00 Cups 2 $0.10 String (5') 1 $0.50 Hot Wheels Track 3 $1.20 Toy Helicopter 1 $6.00 Calculator 1 $3.00 Golf Tee 1 $0.33 Golf Balls 2 $1.00 PVC Pipe (2"X1') 1 $0.75 Note Cards 6 $0.30 Foam Board 1 $0.25 Total Estimated Cost: $19.93

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Testing Results:

During the construction process, group C1-01 tested each portion of the PAR 6 device as it was constructed. Once each next step was constructed, the step was tested. Upon completion of the test, the step was then introduced to the system and the system was tested as a whole. Eventually, the entire PAR 6 device passed testing with 95% reliability, factoring human error. However, during demonstration, the PAR 6 device failed to accurately perform the desired functions of turning on the calculator and launching the helicopter. Group C1-01 feels that this was most likely due to environmental factors such as the pitch of the table or floor and one human error on the first demonstration (team member did not place string on mousetrap correctly). The consensus concerning the environmental failure was reached after discovering the most other groups in the C1 lab faced similar malfunction problems with their devices, and after discovering that the PAR 6 device functioned flawlessly when placed in sequence with the other C1 devices in another portion of the room. Therefore, group C1-01 should have tested the PAR 6 device on its intended operational surface before its scheduled debut.

Conclusions:

Although the PAR 6 device was not successful during its presentation, it did prove to be a complete success during testing and in operation with other devices in the C1 lab. Group C1-01 concluded that the failure at presentation was due to a pitched platform and human error. Other than the presentation malfunction, group C1-01 faced several other difficulties during the construction phase of the project. These difficulties included: achieving the correct angle for the zip line portion of the device, displaying the device title during the collision portion of the device, positioning the wheel in order to drop the golf ball on the second portion of the track, and designing the trap door mechanism to interact properly with the first portion of track. Given more time, group C1-01 would attach a pitch system to the base of the device in order to compensate for environmental variations, reinforce the connection between the control string and mousetrap, and formulate a better method for controlling the flight path of the helicopter. Group C1-01 feels that these changes would effectively increase the reliability of the PAR 6 device with minimal cost increase.

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References:

Appendix A: Calculations page courtesy of Brandon Sanders

EF151 Rube Goldberg Device Description Page: http://ef.engr.utk.edu/ef151-2010-01/tm/final-project.php

Appendix A: