MECH307
DESIGN PROJECT
Spring, 2000
"Widget Inspection"
A
manufacturer wishes to perform automated inspection at the end of its assembly
line to result in better quality control of its product. The widget produced by
the line has a rectangular shape with an off-center hole (see figure below). Due
to flaws in the manufacturing process, sometimes the hole is not present. The
manufacturer wants a system that can separate and count "good" (with hole) and
"bad" (without hole) widgets automatically, quickly, and reliably.
Each group must design and build a widget inspection device.
Your group's grade for the project will be based on the level of performance that
your device achieves and on several scoring adjustments as described below.
Levels of Performance
The levels of performance
along with their corresponding scores (based on a scale of 100) are: Level
0 (0)
No device.
Level 1 (65)
You place a single widget
into your device and press a single button (with mechanical and/or electrical
action). If the widget is "good" your device should turn on a green LED,
and if it is "bad" your device should turn on a red LED. The device must
work for several "good" and "bad" widgets, one at a time.
Level 2 (75)
Level 1 plus your device should provide a digital display of a running count
of the number of "good" widgets and the number of "bad" widgets. The number
of "good" and "bad" widgets will each be limited to a maximum of five; thus, only
single digit displays are required. Your device must have a reset button
so the counts can be returned to zero at any time.
Level 3 (85)
Level
2 except your device must first be pre-loaded with five "good" widgets and five
"bad" widgets, stacked face to face in random order and hole orientation.
Your system must then process (test and discharge) a single widget with each press
of the button, until all ten widgets have been processed.
Level 4 (95)
Level 3 except your device must process (test and separate) all ten widgets
automatically after a single push of the button. If less than ten widgets
are loaded, your device must detect this and display a signal (e.g., turn on a
yellow LED) after all of the widgets are processed.
Grading
Adjustments
- ±5 for level of effort, creativity, and
initiative (-5: poor; 0: average; 5: exceptional)
- ±5
for aesthetics, construction quality, and consumer appeal (-5: poor; 0:
average; 5: exceptional)
- ±5 for actual construction cost and
expected mass production cost (-5: expensive; 0: average; 5: inexpensive)
-
±10 for the final project report. A positive adjustment will be given
for a well written and well illustrated report. (-10: poor; 0: average;
10: exceptional)
NOTE - The potential for
a positive adjustment increases with the level of performance. A maximum
positive adjustment is possible only for a Level 4 device.
Extra
Reward: - +5 (max) for a presentation in class during the last week
of the semester (by invitation only)
Notes:
- Your TA will try to provide you with any circuit components you need (resistors,
capacitors, LEDs, limited IC's) and Walt can supply you with limited building
materials and mechanical hardware. You are responsible for purchasing other
stuff (special IC's, micro switches, photo-optic pairs, miscellaneous mechanical
and electrical accessories, etc.). See useful
local vendors.
- If your device fails to satisfy a level's requirements
exactly or if your device's performance falls between two levels, the score will
be adjusted accordingly.
- Official trials will be during the Lab section
meetings in the latter part of the semester and during other hours arranged by
your TA (e.g., TA office hours). No trials will be allowed after the last
class day of the semester. You may use multiple trials to progressively
improve your Level score. A group is allowed only one official trial per
week. Every group must also show their device during the last Lab section meeting
for final evaluation of the grading adjustment categories. You are welcome
to invite family and/or friends to the final Lab section meeting to see everybody's
designs.
- Selected groups will be invited (by your Instructor) to present
their projects to the entire class during the last two lecture periods of the
semester (see "Extra Reward" above).
- The final report is due at the
last meeting of your Lab section. The report must include:
- title page with title, group number, group member names, date, etc.
-
Design Summary: concise overview of how your device works. Include a well-labeled
overall figure illustrating your device.
- Design Details: detailed figures
(where necessary and/or helpful) and circuit diagrams. Be sure to refer
to the figures and diagrams and describe them completely. The circuit diagrams
in this section of the report should be well illustrated functional block diagrams;
detailed pin-out wiring diagrams should be included in an Appendix.
- Design
Evaluation: describe the level of performance and provide justifications for grading
adjustments.
After looking at the figures and schematics and after
reading the brief descriptions in the "Design Summary" and "Design Details," the
reader should be able to fully understand how your device functions. -
Theoretically, the highest possible score (for a device awesome in every way and
presented well) is 125 on a scale of 100. Theoretically, the lowest possible
score (for no device) is -25.