Engineering design project

*While the idea of a mousetrap racer is of unknown origin, the format of this specific assignment is adapted from an assignment by Mukul Talaty, PhD.

OBJECTIVE

Your goal is to design a vehicle that can travel independently (once you spring the trap) and complete the following tasks:

(1) Travel as far as possible (maximum distance) on a smooth, mostly level tile floor (like that of our classroom)

(2) Choose ONE of the following tasks:

a. Successfully pull a load a minimum distance (i.e., design for power)

b. Successfully travel to and stay in a designated area (i.e., design for accuracy)

You will get to choose on which one of the last two objectives you will be evaluated, but you must make that choice before testing.

Grading

Grading will be based on the following criteria:

1. Performance: did your design achieve the requirements stated above. (bonus points for best in class)

GRADE PERCENTAGE: 35% + bonus points

2. Written and oral (in-class presentation) – details below

GRADE PERCENTAGE: 65%

a. Engineering drawings in SolidWorks and/or AutoCAD GRADE PERCENTAGE: 10% (part of report grade) The project will be done in groups of 3 or 4 (5 groups total).

MATERIALS

Your group will be given one (1) mouse trap. You must use the mousetrap you are given – you can’t go out and buy a better one. If you ruin your mousetrap, you must buy a replacement from me for 10% of the performance grade. (=3.5% of total grade).

In addition, your group gets to choose 10 items from the following list. Certain items can be ‘doubled’ (e.g., you may buy two pairs of wooden wheels) but they will each count as an item.

PARTS LIST

1. 12”x 3” x 3/32” sheet of Basswood (or similar) wood

2. 8½” x11” piece of corrugated cardboard

3. 2 blank audio CDs (you may double up on this item, but it will count as 2 of 10)

4. 2 wooden wheels (you may double up on this item, but it will count as 2 of 10)

5. masking or duct tape 2 – 6” pieces

6. 2’ piece of string

7. 2’ piece of fishing line

8. 12” length of 3/16”steel rod

9. 12” length of 1/8” steel rod

10. 12” length of 1/8” wooden dowel

11. 2 wooden pencils

12. 2 Popsicle sticks (you may double up on this item, but it will count as 2 of 10)

13. 4 small washers (you may double up on this item, but it will count as 2 of 10)

14. 6 paper clips (large)

15. 2 straws

16. 2 “zip” ties

17. 4 eye hooks (you may double up on this item, but it will count as 2 of 10)

18. A “small” custom part that you may print on the 3d printer. Specifications of this part are somewhat flexible and subject to the instructor’s approval and the limitations of the MakerBot printer (model: Replicator 2)

In addition to the parts above, you may use all the hot melt glue you want, but you cannot fabricate parts out of hot glue! It is only to be used as an adhesive.

REQUIREMENTS

1. You are allowed ONLY what materials you select from those that are listed above. Once you choose materials, you cannot change your selections.

2. The vehicle must be built using only the tools in our lab (*exceptions to this are possible and will be considered on an individual basis, subject to my discretion)

3. You are allowed hot glue only to bond pieces together, but not to fabricate any sort of part or material for any use other than to fasten. Coincidental function, other than fastening, is allowed so long as the fastening is the primary purpose and that purpose is clearly explained.

4. All fabrication will be done during class time and in our lab. (In other words: no, you can’t take it home with you and build it with your friends.) It is permissible to meet outside of class time to work on your design, the report, the presentation, etc.

5. You should have fun doing this project. However, I will hold you to professional standards of behavior:

a. You must follow proper laboratory safety rules, including proper dress (especially footwear) in the lab/shop room.

b. You will be expected to behave in a safe and professional manner while constructing your racer: e.g., tools should be used in a safe manner, no poking your groupmates with sharp things, no profanity.

c. You are expected to behave honorably: do not tamper with any other group’s design.

DUE DATES

1. Vehicles will be due at the end of class (10AM) WEDNESDAY, APRIL 27, 2016. The last class (Friday, April 29) will be used to run the cars through the specified objectives.

2. Presentations will be given to the entire class and final reports will be due at our scheduled final exam time, 8:30 AM MONDAY MAY 2. The instructor will provide donuts.

REPORTING REQUIREMENTS

The written report (HINT: this is a DESIGN PROJECT)

1. Objective (more than “We have to build a car for this project…”) 2. Design criteria, material constraints 3. Background section:

a. Do a little research on mousetrap racers. Describe them (pictures are fine). How do they usually get power from a mousetrap? Are there several different ‘basic’ methods or does everyone do this the same way?

b. Give me an indication of how your group is approaching this project. What is your “guiding principle” that you hope will lead you to glory? [for example: minimize weight, maximize length, minimize friction, maximize energy recovery, etc.

4. A description of the alternate solutions YOUR GROUP came up with (at least 3 total) including drawings (can be hand sketches – but should clearly show the interesting features of each alternate design) and why you ultimately rejected them.

a. These should be ‘reasonable’ – suggesting that you thought about making it out of titanium and carbon fiber composite, but rejected this because none of the items on the parts list are made of titanium or carbon fiber is not a reasonable alternative solution.

5. A detailed description of the final design – describing specifically why you thought this design was the best. What were the tradeoffs with the other designs? This must include both

AutoCAD and SolidWorks drawings

a. NOTE: you can include drawings of subassemblies in one program and the completed design in the other program; that is, you should not put in the same drawing drawn with two different programs.

6. Results of any preliminary testing you were able to perform

7. If you did testing that led to design changes, what the changes were and how you arrived at these changes?

8. PARTICIPATION: I would like a section detailing each group members’ participation in the project: “Bob was responsible for the drawings in SolidWorks; Joe created the PowerPoint presentation, Mary was the lead builder of our racer.” If someone was absent for a significant part of the build, this should be reported here.

PLEASE use the outline/guidelines for writing a report that we have (hopefully) been using all semester long.

The Oral Presentation

The salient (important) points of your design process and final design should be presented in a 10-15 minute slide presentation, followed by 5 minutes for questions by the class.

1. All group members must participate in the final presentations. In other words, everyone has to talk.

This is not just the instructor being cruel, this is to help you overcome your anxiety about talking in front of people. This class is the least intimidating place you will ever present; take advantage of the opportunity.

2. The presentation should be professional, succinct, and hit the major highlights of the project (you may choose which of the above sections/steps to include/not include).

3. Your presentation must be between 10-15 minutes in length (Practice it! Going over-time will count against the score in this section). There will be 5 or so minutes for questions directly following the talk (while the next group sets up).

4. Use slides: use presentation software that can be presented in class from the instructors’ PC (I strongly suggest Microsoft PowerPoint as I’m sure that’s available and I can help if there are any technical difficulties, but if you insist on using a Mac and some other software, YOU are responsible for making sure it’s going to work.)

The group that performs the best in each category will receive 5 bonus points (i.e. 15 bonus points are up for grabs and up to 3 groups can win, barring any ties).

GRADING

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