MECH307 - DESIGN PROJECT
group must design and build a combination security lock device controlled by digital
electronics and/or a PIC
microcontroller. Your device must contain the following minimum set
of functional elements:
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.
- three switches (labeled A, B, and C) that will
be used to enter a combination
- a button (labeled ENTER) used to process
the input (the states of A, B, and C) and perform the appropriate function as
- a green LED labeled OPEN and a red LED labeled ALARM
used to indicate the result of a combination attempt
of PerformanceThe levels of performance along with their corresponding
base scores (based on a scale of 100) are:
Level 0 (0)
or non-functioning device.
Level 1 (60)
When the ENTER button is
held down, the green LED should be on if the A/B/C switches match the desired
combination and the red LED should be on if there is a discrepancy. The
LEDs should be off when the ENTER button is up. The correct combination
must be pre-programmed inside of your device (e.g., with a small set of DIP switches
or with constants in a PIC program).
Level 2 (70)
Level 1 plus your
device should keep track of and display the number of failed attempts since the
last valid combination. We only require a count up to nine so a single 7-segment
LED display will suffice. The display should reset to zero when the valid
combination is entered.
Level 3 (80)
Level 2 plus your device must
also sound a buzzer or alarm for approximately 3 seconds when an incorrect combination
is entered. If the correct combination is entered during an alarm, the alarm
should be turned off immediately.
Level 4 (90)
Level 3 plus your
device must also contain some sort of actuator (e.g., solenoid, dc motor, or stepper
motor) that performs some interesting function (e.g., unlatches and springs open
a locked door) when the correct combination is entered. We want you to be
creative with the action and function of the actuator and the intended use of
Grading Adjustments (added to or subtracted
from the base level score)
- +/- 5 for construction quality,
aesthetics, consumer appeal (e.g., perforated protoboard with neat soldered wiring
vs. messy breadboard; well-built and attractive packaging) (-5: poor; 0:
average; 5: exceptional)
- +/- 5 for level of effort, initiative, and
research (-5: low; 0: average; 5: high)
- +/- 5 for actual
construction cost and expected mass production cost appropriate for the level
of performance (-5: expensive; 0: average; 5: inexpensive)
+ 5 [for Level 4 only] for creativity, originality, and usefulness
(0: average; 5: exceptional)
- +/- 10 for the final project report
per the requirements below (-10: poor; 0: average; 10: exceptional)
- The potential for a positive adjustment increases with the level
of performance. A maximum positive adjustment is possible only for a Level
4 device (especially for the final report adjustment).
- +5 (max) for a presentation in class during the last week
of the semester (by invitation only)
- 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, switches, buttons, miscellaneous mechanical
and electrical accessories, etc.). See useful
- We recommend that you work together as much as possible
with your group members, but the project work may be more manageable if you divide
tasks among the group members. The entire group is still responsible for
the work (e.g., if one group member doesn't do their parts, the other members
must take up the slack and evaluate the non contributing member accordingly).
Here is an example of a list of duties you may want to distribute among your group
- project management (schedule meetings, plan and monitor
progress, budget and collect for purchases, foster communication, etc.)
product and component research and purchasing
- mechanical hardware design,
assembly, and testing
- electronics design, assembly, and testing
PIC microcontroller programming and interfacing
- design documentation
and report writing
- 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
- 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 should include:
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.
- title page with title, group number, group member names, date, etc.
Design Summary: concise overview of what your device does and how it works.
Include a well-labeled overall figure illustrating your device.
Details: detailed figures (where necessary and/or helpful), circuit schematics
and/or functional diagrams, and software flowcharts (if applicable). Be
sure to refer to the figures and diagrams in the text and describe them completely.
Include detailed wiring diagrams (if details are not included in earlier figures)
and well commented software listings (if applicable) in an Appendix and refer
to them in the body of the report.
- Design Evaluation: describe the level
of performance and provide justifications for the grading adjustments.
- Theoretically, the highest possible
score (for a device and effort awesome in every way and presented well) is 125
on a scale of 100!