EE223 Laboratory
Design Laboratory Sequence 2015
Learning Objectives
1) Learn how to design functioning electronic circuits
2) Learn how to work as a consultant, including proposal submission, statement of work
completed (SOW), and billing
3) Gain experience in the design/build/debug cycle
4) Gain experience in working in a design team
5) Practice giving oral reports
Overall
The Design Laboratory Sequence will take place over the lab periods in Table 1. During
this time your lab team will decide on a project to complete and submit a proposal, order
parts, design, build, and debug the circuit, and submit a statement of work completed as if
hired as a consultant. The sequence will culminate with presentations.
Landmark and suspense dates are as follows. Graded items are in bold.
Table 1
19 Oct
26 Oct
2 Nov
9 Nov
16 Nov
23 Nov
30 Nov
Read Design Lab. Decide which project to build, or one of your own.
Discuss individual projects with professor.
Submit graded written proposal. Order parts. Build circuit.
Debug circuit (they never work the first time!)
Final debugging of projects. Work on presentations and SOW.
Extra Monday in schedule. Optional attendance extra help day.
Oral presentations, written statement of work (SOW)
Possible Project Choices
Battery load tester. Typical battery testers measure the “no-load” voltage of a battery,
which can be deceiving, since partially discharged batteries show a normal voltage when
not loaded but show a pronounced drop when connected to a circuit. Battery load testers
are available for car battery testing, but cost about $100. Design a battery load tester for
any type of battery of your choosing. Use a comparator to light a green LED if the
battery is good, a yellow LED if the battery is partially discharged, and a red LED if the
battery is fully discharged.
Frost warning device. Develop a system to be used by farmers that alerts them to the
first frost. Develop this around a thermistors and comparator to test whether the
temperature is below freezing. If it is, sound an alarm (a speaker). BONUS: create a
snow alarm that sounds the alarm if it is both below freezing and there is moisture
between two electrodes (i.e. the resistance between the electrodes drops). You will have
2
to figure out a simple way to heat the area around the electrodes to ensure the snow melts
enough to trigger the moisture-sensing electrodes.
Sonar sound effects. Design a system that duplicates the decaying-sinusoid sound of a
sonar ping to be used in an Epcott Center attraction in Disney World.
Drag-race countdown timer. Use LED’s for the lights. A thrown switch can start a RC
circuit charging, and comparators can light the LED’s in sequence. Sound an alarm when
sequence is completed.
LED spectrum analyzer. Design a system to be used in a home entertainment system that
measures the bass and treble ranges of an amplifier. Use at least 4 LED’s to monitor the
power level outputs of each tone.
Laser-based security system. Use a pen-style laser and a CdS cell (light-dependent
resistor) to trigger a comparator whenever someone crosses the laser path. A momentary
interruption should sound an alarm for 10 seconds (send the output from a decaying RC
circuit to a second comparator to do this).
Christmas tree watering sensor. Design a system using opamps that senses the water
level in a Christmas tree stand, and warns (blinking LED? sound?) when the water is
low. BONUS: include a method to alert the user when adding water to the stand that the
stand is full.

If you have an interest in a different project, email me immediately and I will evaluate
it to see if it is suitable.

Figure out what parts you will need to order ASAP. It can take two weeks for parts to
arrive; many cadets discover they need to then redesign their projects to use a
different part and run out of time.
Proposal
The proposal (due date in Table 1) should provide:
1) circuit specifications (quantify what the circuit will do, at what voltage/time LED’s
will light, etc.)
2) a proposed circuit diagram, with component values and their calculations
3) estimated time for each major phase (e.g. proposal, ordering parts, build & debug
section 1, build & debug section 2, combine sections, write statement of work, etc.)
4) estimated cost for project. Consider your time as a junior engineer billable at
$50/hour.
3
Parts Ordering
You may need to order parts for your project. To do this, locate parts from either
www.mouser.com or www.jameco.com . We cannot purchase parts from other vendors,
although if you wish to do so on your own, unreimbursed, you may and keep the parts
when done. When you submit your order form to me, electronically, it should look like
the below in an excel spreadsheet so it doesn’t run off the page margin. Do it quickly and
plan for a 7 day delay between my date of taking orders and receiving the item. Most
common problems: 1) student did not check to see if item was in stock; quantity on hand
is listed on the website 2) student did not include a valid link to the product webpage 3)
student ordered a miniature surface mount IC instead of a through-hole DIP IC that can
be used in a protoboard.
www.Mouser.com
4 512-QSD2030
2 604-DC10GWA
photodiode
LED bargraph
each tot
students
0.23 0.92 Smith & Jones
1.24 2.48 Smith & Jones
link
http://www.mouser.com/7736
http://www.mouser.com/2445
Statement of work
Include the circuit schematic you designed, its specifications, and a detailed description
explaining how it works. Include supplemental graphics to aid explaining difficult
concepts. Itemize the bill including hours spent and materials. Describe problems
encountered, and how you solved them. Recommend improvements or extensions to
your design.
Specifications are important. A “specification” means a list of inputs and outputs, and
how they relate. A specification does not say how the circuit operates, just what it does.
Example: “The project specification is a plastic project box, no larger than 2” x 4” x 8”,
that is battery powered, and has a power switch and a light sensor, and drives an LED.
When illuminated by light, either inside fluorescent or outdoor sunlight, the LED will be
off, and when in relative darkness (e.g. a classroom with lights off and blinds pulled) the
LED is on.”
Real-world engineering advice: Before doing any work, write your proposed project
specification and get it approved by the client before you do work. Then when you are
done with the work you can present the product to the client and show that it meets the
specification. This is an important part of real-world engineering because the client
rarely (never) articulates what he/she wants well…it will come out more like “I want a
box that turns a light on when it gets dark”. Then you build it, and discover he meant that
it should be a UL-listed outdoor junction box that turns on a halogen security light, and
the work you did is useless. Or equally bad, the customer loves your work but wants an
extra feature added (“it should have a manual override switch”) which you’d be happy to
do for extra money, but did not think he originally wanted. Writing a good specification
statement, and having the customer signing it before starting the job, prevents these kind
of misunderstandings and keeps you and the client happy.
4
Presentation
Each group will have 10 minutes to present their project and 2 minutes question and
answer time. Bring your laptop with the presentation loaded and ready to present. Bring
it also on a backup USB key in case you have trouble connecting your laptop to the
projector. Don’t bet your grade that your laptop will connect perfectly – it is too easy for
something go wrong and then your group will have nothing to show. (I’ve seen this
disaster happen both at cadet presentations and at professional conferences.)
Grading
The grading for your project will be broken out as detailed below. This is the same form
you will receive with your graded project.
Proposal 10%
D
Very Weak
35%
35%
15%
15%
C
Weak
Low Ave
High Ave
B
Strong
A
Exceptional
Content
Organization
Readability
Grammar
Device itself 50%
D
Very Weak
25%
25%
25%
25%
C
Weak
Low Ave
High Ave
B
Strong
A
Exceptional
Complexity
Quality of design
Quality of construction
How well it works
Statement of Work 20%
D
Very Weak
20%
20%
20%
20%
20%
Specification
Schematic
Materials list
Description
Readability
C
Weak
Low Ave
High Ave
B
Strong
A
Exceptional
5
Presentation 20%
D
Very Weak
30%
30%
25%
15%
C
Weak
Low Ave
High Ave
B
Strong
Content
Delivery
Organization
Q&A
Definitions:
Content: The depth, development of ideas, quality of argument
Organization: The sequencing of the whole and coherence of the parts
Readability: Fluency of the prose
Quality of design: As evidenced in the Statement of Work and Presentation
Quality of construction: As evidenced by instructor’s assessment of device itself
Delivery: Professionalism, enthusiasm, lack of distracting mannerisms, timeliness
Plan Ahead!
A
Exceptional