Senior Thesis - ESP - Final

University of Nebraska-Lincoln
College of Engineering
Computer and Electronics Engineering Department
CEEN 4990
Efficient Student Parking (E.S.P.)
By
Daniel Hamrick
Kyle O’Doherty
Elliot Triplett
Submitted in Partial Fulfillment of the Requirements for the B.Sc. Degree,
Computer and Electronics Engineering, College of Engineering,
University of Nebraska
Peter Kiewit Institute, Omaha, Nebraska, U.S.A.
May 2012

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Final Report
I. ETHICAL DESIGN STATEMENT
Team E.S.P. has periodically reviewed the IEEE Code of Ethics and has applied the design process to the final
proposed design. Though out the planning, design and construction process all project engineers held public safety
as the highest concern for this project and the E.S.P. project reflects that distinctly.
II. ENVIRONMENTAL IMPACT STATEMENT
Team E.S.P. has taken into high consideration the environmental effects of the parking lot detector and has opted
for lead free – RoHS compliant components wherever possible.
III. PROJECT ABSTRACT
The E.S.P. system allows drivers to better utilize parking spaces across the University of Nebraska campus by
allowing them to see the availability of parking spaces on a website, accessible from any mobile device. Consisting
of four induction loops, a tracking computer and a server to host the client access, our product will autonomously
and passively monitor vehicle traffic without pedestrian interference.
The induction loops are buried in the road and generate a small magnetic field that is altered as metallic objects
pass over the system. This change is registered by the tracking computer and sent to the server with a system
status message over an Ethernet connection. The server then stores this data locally and provides a visual
representation of the traffic volume to the user as well as a remote access capability to campus parking
administrators.
IV. ACKNOWLEDGEMENT
The Efficient Student Parking team would personally like to thank the faculty and staff at the University of
Nebraska for all of the council, assistance and patience over these past four years as we worked towards this goal.
The team would also like to thank our friends and family for all the support they have provided to help us succeed
during the project and in our education.
The following individuals were involved in this projects design, development and approval:
Resource Manager – Daniel Hamrick
Hardware Engineer – Kyle O’Doherty
Software Engineer – Elliot Triplett
Senior Project Officer – Professor Herb Detloff
Parking Office Manager – Jim Ecker

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V. EXECUTIVE SUMMARY
The Efficient Student Parking project was undertaken based on personal experiences of the team and fellow
classmates regarding difficulties in parking on the University of Nebraska campus. Our team wanted to come up
with a product that was cheap enough for a state school to purchase and implement yet our greatest challenge
was devising a system that would be adaptable to the different parking lot styles, configurations and individual
challenges while still maintaining a high level of accuracy.
The solution for this problem evolved into a common vehicle detection method used in street light sensors and
automatics driveway gates. This solution was selected based on the cost of materials to construct, accuracy, and
the ability to not be triggered by pedestrians. In the final version of E.S.P. the team was able to demonstrate a
highly accurate vehicle detection system that could be adapted to several environments and parking lot styles
using variable components and deployment configurations of the induction loops. The success of the project was
demonstrated using a set of individual performance tests and acceptance testing to provide system viability and
standard certification. These tests include verification that a vehicle can be detected even at speeds of 35 mph
entering or exiting the parking lot and accuracy verification of detection of 106 out of 106 vehicle transitions.
Additionally, the client was verified to work on Safari, Firefox, Internet Explorer and Chrome web browsers on both
laptops as well as smartphone platforms all while being updated within 20 seconds of a change in the system.
In its current form, the E.S.P. system has the potential to be deployed immediately; however, given the
opportunity to develop this product our team has several suggestions. First, would be to further develop the client
interface to a more professional looking and feature rich product that would then be adapted to a cellphone based
application. Second, would be the development of a marquee display that would connect to the system to display
a clear and obvious indication of parking availability when driving by the parking lot entrance. Finally, the local
node has a few items that would need to be changed; specifically from our reliability analysis we found that our
3.3V and 5V regulators have a 9.1 and 17.6 year Mean Time to Failure respectively, an unacceptable rate for a final
commercial product.

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Final Report
TABLE OF CONTENTS
i. Ethical Design Statement.......................................................................................................................................2
ii. ENVIRONMENTAL Impact Statement ....................................................................................................................2
iii. PROJECT Abstract..................................................................................................................................................2
iV. ACKNOWLEDGEMENT ..........................................................................................................................................2
v. Executive Summary...............................................................................................................................................3
List of Figures and Tables...............................................................................................................................................8
1.0 Introduction...........................................................................................................................................................11
2.0 Problem Formulation.............................................................................................................................................14
2.1 Problem Statement............................................................................................................................................14
2.2 Background........................................................................................................................................................15
2.2.1 Introduction – Patent analysis....................................................................................................................15
2.2.2 Results of Patent and Product Search ........................................................................................................15
2.2.3 Analysis of Patent Liability..........................................................................................................................18
2.2.4 Action Recommended ................................................................................................................................19
2.2.5 Summary.....................................................................................................................................................19
2.3 Problem Formulation.........................................................................................................................................19
3.0 Project Design Requirements, Specifications and Success Criteria .......................................................................20
3.1 Introduction.......................................................................................................................................................20
3.2 Objective Tree....................................................................................................................................................21
3.3 Project Common Success Criteria......................................................................................................................21
3.4 Project Specific Success Criteria ........................................................................................................................22
3.5 Deliverables .......................................................................................................................................................23
3.6 Constraints.........................................................................................................................................................23
4.0 Concept Development, Synthesis and Process Description ..................................................................................24
4.1 Literature Review...............................................................................................................................................24
4.2 Concept Generation...........................................................................................................................................24
4.3 Concept Reduction ............................................................................................................................................25
4.4 Project Schedule................................................................................................................................................29
5.0 Detailed Engineering Analysis and Design Product Presentation..........................................................................31
5.1 Engineering Analysis..........................................................................................................................................31
5.2 Product Presentation.........................................................................................................................................35
5.2.1 Introduction – Packaging Description.........................................................................................................35
5.2.2 Commercial Product Packaging ..................................................................................................................35

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5.2.3 Project Packaging Specifications.................................................................................................................36
5.2.4 PCB Footprint Layout..................................................................................................................................39
5.2.5 CAD Schematics and Illustrations ...............................................................................................................40
5.2.7 Tools Requirement .....................................................................................................................................41
5.2.8 Estimated Weight .......................................................................................................................................42
5.3 Hardware Design ...............................................................................................................................................42
5.3.1 Introduction – Hardware design review .....................................................................................................42
5.3.2 Theory of Operation ...................................................................................................................................42
5.3.3 Hardware Design Narrative ........................................................................................................................43
5.3.4 Summary.....................................................................................................................................................44
5.3.5 Schematic....................................................................................................................................................45
5.4 PCB Design.........................................................................................................................................................46
5.4.1 Introduction – PCB design ..........................................................................................................................46
5.4.2 PCB Layout Design Considerations - Overall...............................................................................................46
5.4.3 PCB Layout Design Considerations - Microcontroller.................................................................................47
5.4.4 PCB Layout Design Considerations – Power Supply ...................................................................................48
5.4.5 Summary.....................................................................................................................................................48
5.4.6 PCB Layout..................................................................................................................................................49
5.5 Firmware Listing ................................................................................................................................................50
5.5.1 Introduction................................................................................................................................................50
5.5.2 Software Design Narrative..........................................................................................................................50
5.5.3 Summary.....................................................................................................................................................51
6.0 Economic Analysis .................................................................................................................................................52
6.1 Cost Analysis......................................................................................................................................................52
6.2 Bill of Materials..................................................................................................................................................55
7.0 Reliability and Safety Analysis ...............................................................................................................................57
7.1 introduction.......................................................................................................................................................57
7.2 Reliability analysis..............................................................................................................................................57
7.3 Safety Analysis ...................................................................................................................................................59
7.4 Failure mode, effects, and criticality analysis....................................................................................................60
7.5 Summary............................................................................................................................................................60
8.0 Social/Political/Environmental Impact ..................................................................................................................62
8.1 Introduction.......................................................................................................................................................62
8.2 Social Responsibility and Ethical Impact Analysis..............................................................................................62

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8.3 Political Impact Analysis ....................................................................................................................................63
8.4 Environmental Impact Analysis .........................................................................................................................63
8.5 Summary............................................................................................................................................................64
9.0 Discussion, Conclusions and Recommendations...................................................................................................65
9.1 Project review....................................................................................................................................................65
9.2 Conclusions........................................................................................................................................................65
9.3 Recommendations.............................................................................................................................................66
10.0 User’s Manual......................................................................................................................................................68
10.1 Introduction.....................................................................................................................................................69
10.2 CONSIDERATIONS ............................................................................................................................................69
10.3 Induction loop instructions..............................................................................................................................69
10.3.1 Preparing for installation..........................................................................................................................69
10.3.2 CUTTING the Pavement Slots ...................................................................................................................70
10.3.3 FORMING the Loop...................................................................................................................................70
10.3.4 PREPARE the loop lead wires....................................................................................................................70
10.3.5 SEALING the loop......................................................................................................................................71
10.4 Local Node Maintenance.................................................................................................................................72
10.4.1 Connections..............................................................................................................................................72
10.4.2 Tuning .......................................................................................................................................................73
10.4.3 MENUS......................................................................................................................................................73
10.5 Server User manual .........................................................................................................................................75
10.6 System Requirements......................................................................................................................................75
10.7 Startup and Operating Instructions.................................................................................................................75
10.7.1 Startup ......................................................................................................................................................75
10.7.2 Administration..........................................................................................................................................76
10.7.3 Logging and Troubleshooting ...................................................................................................................77
11.0 Appendices ..........................................................................................................................................................78
A. Notes ...................................................................................................................................................................78
B. Engineering change requests ..............................................................................................................................78
C. Electrical Specifications .......................................................................................................................................81
Schematics...........................................................................................................................................................81
Timing Analysis ....................................................................................................................................................83
Loading Analysis ..................................................................................................................................................84
Specification Sheets.............................................................................................................................................84

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Signal Quality Analysis (SQA)...............................................................................................................................84
Safety/Electrical Hazard Checklist .......................................................................................................................84
Accuracy Certification..........................................................................................................................................85
D. Software..............................................................................................................................................................85
Flowcharts ...........................................................................................................................................................85
Program Listings ..................................................................................................................................................88
E. Resource Expenditure Analysis............................................................................................................................96
Cost analysis ........................................................................................................................................................96
Labor Hour analysis .............................................................................................................................................98
F. Project purchases.................................................................................................................................................99
G. Other Resources................................................................................................................................................103
One page project manager................................................................................................................................103

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Final Report
LIST OF FIGURES AND TABLES
Figure 1 - North Campus Parking.................................................................................................................................11
Figure 2 - South Campus Parking.................................................................................................................................11
Figure 3 - Project Stakeholders....................................................................................................................................12
Figure 4 - Patent Search Functions..............................................................................................................................15
Figure 5 - Objective Tree..............................................................................................................................................21
Figure 6 - PCSC Listing..................................................................................................................................................21
Figure 7 - PSSC Listing..................................................................................................................................................22
Figure 8 - Tracker Implementation Comparison..........................................................................................................25
Figure 9 – Methods Table............................................................................................................................................25
Figure 10 - Pros / Cons Table.......................................................................................................................................26
Figure 11 - Pairwise Comparison .................................................................................................................................27
Figure 12 – Decision Chart...........................................................................................................................................27
Figure 13 – Project Schedule .......................................................................................................................................29
Figure 14 - Concept Design 1.......................................................................................................................................31
Figure 15 - Concept Design 2.......................................................................................................................................31
Figure 16 - Final Tracker Design...................................................................................................................................32
Figure 18 - Envelope Detector Simulation...................................................................................................................33
Figure 17 - Envelope Detector Circuit..........................................................................................................................33
Figure 19 - Tracker Circuit Prototype...........................................................................................................................33
Figure 21 - PVC Induction Loop (2) ..............................................................................................................................34
Figure 23- Tracker Circuit Prototype Waveforms (Simulated Car) ..............................................................................34
Figure 20 - PVC Induction Loop (1) ..............................................................................................................................34
Figure 22 - Tracker Circuit Prototype Waveforms (No Car).........................................................................................34
Figure 24 - 610 Loop Vehicle Detector ........................................................................................................................35
Figure 25 - TC-2BL44-R Inductive Burial Loop Vehicle Counter...................................................................................36
Figure 26. AMU1084CCHF 10"x8"x4" fiberglass enclosure .........................................................................................36
Figure 27 - NEMA 4X Specifications.............................................................................................................................37
Figure 28 - Appleton 4CS-1-2.......................................................................................................................................38
Figure 29. Appleton 2510 Duplex Cover.....................................................................................................................38
Figure 30 - 5-15R..........................................................................................................................................................38
Figure 31 – Enclosure Dimensions...............................................................................................................................40
Figure 32 – Enclosure Materials ..................................................................................................................................41

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Figure 33 – Data Ports .................................................................................................................................................43
Figure 34 – Logic Converters .......................................................................................................................................43
Figure 35 – Atmega Functional Flow Chart..................................................................................................................45
Figure 36 – Image of Project PCB.................................................................................................................................46
Figure 37 – PCB Schematic ..........................................................................................................................................49
Figure 38 – Project Funding by Category.....................................................................................................................52
Figure 39 – Chart of Total Budget Spent......................................................................................................................53
Figure 40– Chart of Budget Spent by Category ...........................................................................................................53
Figure 41 – Table of Example Man Hours Tracker.......................................................................................................54
Figure 42 - Product Bill of Materials ............................................................................................................................56
Figure 43 - Equation for Failure/10
6
hours ..................................................................................................................57
Figure 44 – Failure Analysis of ATMEGA1284P............................................................................................................58
Figure 45 - Failure Analysis of LD1117AS33.................................................................................................................58
Figure 46 - Failure Analysis of LD1085V0.....................................................................................................................58
Figure 47 - Failure Analysis of MAX764CPA.................................................................................................................59
Figure 48 – Loop Installation curb view.......................................................................................................................69
Figure 49- Loop Installation distance...........................................................................................................................70
Figure 50 – Loop Installation twisted pair ...................................................................................................................71
Figure 51 – Local node labeled....................................................................................................................................72
Figure 52 – Server connection window .......................................................................................................................75
Figure 53 – Server connection interface......................................................................................................................76
Figure 54 – Server Status Interface..............................................................................................................................76
Figure 55 - Original Proposed PSSCs............................................................................................................................78
Figure 56 - PSSCS after ECR..........................................................................................................................................79
Figure 57 - Accepted ECR.............................................................................................................................................80
Figure 58 – Final Schematics 1.....................................................................................................................................81
Figure 59 – Final Schematics 2.....................................................................................................................................82
Figure 60 – Timing Analysis .........................................................................................................................................83
Figure 61 – Safety Stickers...........................................................................................................................................84
Figure 62–System Overview ........................................................................................................................................85
Figure 63–Local Node Flowchart .................................................................................................................................86
Figure 64 – Server User Interface Flowchart ...............................................................................................................87
Figure 65 – Server Message Listener Flowchart..........................................................................................................88
Figure 66 - Investments ...............................................................................................................................................96

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Final Report
Figure 69 – Category Expenses....................................................................................................................................97
Figure 68 – Project Reimbursement............................................................................................................................97
Figure 67 – Individual Investments..............................................................................................................................97
Figure 72 – Kyle Subsection.........................................................................................................................................98
Figure 71 – Daniel Subsection .....................................................................................................................................98
Figure 70 – Elliot Subsection........................................................................................................................................98
Figure 73 – Complete Bill of Materials ......................................................................................................................102

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1.0 INTRODUCTION
The University of Nebraska at Omaha (UNO) and the Peter Kiewit Institute (PKI) are excellent institutions to obtain
a world class education, however, a well known issue among student and faculty alike is the difficulty in finding a
parking spot on campus. Due to the location
close to 72nd and Dodge, it leaves very little
real estate for campus facilities on North
Campus or the Southern Campus around PKI.
With its 15,000+ students, the university has
made several adjustments to help alleviate
the problem, including changes in campus
parking policy and the addition of parking
spaces on North Campus and around the
Business Administration building, Mammel
Hall. Additionally, for the past several years, UNO has relied on the Crossroads parking garage as an off campus
satellite parking lot and has supplied a shuttle service to transport students to
North Campus. This amenity will eventually come to an end as the mall is
looking into new development opportunities.
Because the university is unlikely to add additional parking spaces, it is
important that we as engineers develop a means for allowing students and
faculty to efficiently find available parking on campus. Equipped with
knowledge and experience in computer and electronics engineering, Efficient
Student Parking developed a system which is unique and can only be
accomplished by a technically diverse group of students.
The Efficient Student Parking (E.S.P.) mission is to develop a vehicle detection system to allow people to see an
accurate representation of parking availability.
To have statistical evidence of this need, a survey to obtain data for the records as well as to demonstrate how
UNO needs to improve this facet of its campus facilities was organized. A meeting with the Parking Office Manager,
Jim Ecker, was also scheduled to further research the project environment. Additionally this served to advertise
the project for future investment by the school. As the meeting concluded, team E.S.P. was presented with a
Figure 1 - North Campus Parking
Figure 2 - South Campus Parking

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Final Report
detailed analysis report of the school’s parking system by the office which included all of the statistics needed and
more. Therefore, it was decided to withdraw from administering the survey to the student body as the research
became unnecessary. Using such data as total parking stall counts, student parking activity, and shuttle bus
demand we were not only able to confirm the parking issue we were able to get the support of the parking office
in completing our project.
When it comes to fulfilling the need, project E.S.P. has several potential stakeholders that would be involved as
shown below in Figure 3. The first stakeholders include our senior project officer and the department chair,
Professor Detloff and Dr. Chen. By providing the university with a reliable system able to help facilitate a more
efficient use of the parking lots, the CEEN department would gain recognition on a large scale. This would present
the board of regents the ability to implement this system for all Universities in Nebraska.
UNO parking and campus security can also be considered stakeholders as both would gain tremendous amounts of
parking and traffic data. We would generate statistics as we track parking flow and would allow them to save time
by monitoring different lots at different times of the day based on congestion. Easily overlooked are the students
and faculty, as they are small when it comes to development but will ultimately be the ones gaining from the use
of our product. Lastly, we are our own stakeholders as we have to gain not only the knowledge of how to complete
this project but also could potentially turn a profit if sold commercially. If our solution is implemented, students
and staff would not have to park or drive in circles to wait for openings effectively wasting gas, they would easily
be able to see if it was worth even entering the lot or if the next one down was open, tardiness due to parking
would be a thing of the past, and overall traffic flow would be maintained.
Stakeholder Reason for Investment Role in Project
Professor Herb Detloff Senior Project Officer
Guidance and advice for
project design and
implementation
CEEN Department
Gain department
recognition
Supply test equipment and
facilities
Jim Ecker -
UNO Parking Office
Increase parking efficiency
Referencing and advising to
meet the University’s parking
need
Campus Security Parking lot statistics Reference for statistics
Faculty & Students
Gain parking status and
ability to make decisions
Primary users
Team E.S.P.
Completion of capstone
project
Project Engineers
Figure 3 - Project Stakeholders

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To accomplish such a tracking scheme, team E.S.P. has gone with a method of induction loop detectors. By
designing such a loop allows for all metal chassis of cars to be accurately detected whilst not being falsely triggered
by the many pedestrians that pass through the parking lots.
The rest of this report will be spent discussing the many engineering aspects of the E.S.P. lot detector beginning
with the in depth analysis of the issue at hand. Several other criteria include: Project Design Requirements,
Concept Development, Engineering Analysis, Economic Analysis, Reliability and Safety, Social Impact, and a
complete user’s manual.

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Final Report
2.0 PROBLEM FORMULATION
This section outlines the process and resources used to formulate the problem and a patent liability analysis
comparing previously designed systems and how they compare to the E.S.P. system.
2.1 PROBLEM STATEMENT
While student enrollment at UNO continues to increase, parking availability becomes increasingly scarce, and
attempts to alleviate this problem are limited. Due to restricted real-estate on campus, only a limited number of
parking facilities can be built and doing so can be an expensive endeavor.
The shuttle system at UNO has long served as a means to ease parking woes on campus. In the past, students had
resorted to parking on south campus lots or Crossroads Mall and shuttling to class from these locations.
Crossroads mall is currently expecting to expand development opportunities, thus eliminating student parking for
UNO students, faculty and staff. Additionally, a previously spacious South Campus is currently undergoing many
new developments, including a new business college and student dormitories. Because of these new additions,
many parking lots have been removed in order for these institutions to be built.
Since increasing parking availability through means of increasing volume is not an option, the only alternative is to
increase the efficiency at which students and faculty can navigate parking lots in order to easily find available
spaces. The proposed method for achieving this task is to develop a system which is able to accurately track the
number of available parking spaces in a parking lot. The data gathered from this system will be transmitted to a
central server, where the data will be made available to UNO faculty and staff.
There are many contributing factors to inefficient parking on campus. One of the most profound issues is the fact
that a student must completely traverse a lot in order to determine if there are available parking spaces. The high
volume of traffic leads to over-congested parking lots, which is not only unsafe for pedestrians and other drivers,
but also leads to higher emissions of carbon dioxide.
The goal of this project is to allow the user to know how many available parking spaces are in each lot before
entering the lot. This will be accomplished by two means: the number of available parking spaces will be displayed
on a marquee outside of each lot, and the user will be able to access the information for all lots being tracked via a
web interface.

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2.2 BACKGROUND
2.2.1 INTRODUCTION – PATENT ANALYSIS
The Efficient Student Parking project (E.S.P.) utilizes induction loops to detect a vehicle passing through a parking
lot entrance to track the number of vehicles in the parking lot versus the number of established parking spaces
available in that lot. This information is then displayed via two methods, first and most obvious is a marquee or
LCD display which vehicles driving by can see the remaining spaces. The second is via the internet on a website
which shows the entire UNO campus map and a color coded overlay which describes the space availability as well.
While the use of induction loops is quite common, such as in magnetically controlled gates, at stop lights to detect
traffic and adjust light cycling times, and in some cases on roadways to determine vehicle speed, the possibility of
patent liability could possible stem from how the induction loops are built, what software is used in the sampling
and subsequent use of that data, and how the client website is constructed. This paper will discuss the results of a
patent search for products and functions which are performed by E.S.P. which might infringe upon functions
performed by an existing product or similarly performed under the doctrine of equivalence.
2.2.2 RESULTS OF PATENT AND PRODUCT SEARCH
The primary resource used to research any patent information was the U.S. Patent Office at www.uspto.gov.
Searches were conducted using the patent library as well as the application patent library with the following
search commands respectively;
General Database Application Database
Ttl/(induction and loop and vehicle) Ttl/(parking and space and finder)
Ttl/(parking and space and tracker) Ttl/(parking and lot and finder)
Ttl/(induction and loop and finder) Ttl/(parking and lot)
Ttl/(induction and loop)
Figure 4 - Patent Search Functions

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Final Report
As a result of these searches, several patents were discovered which were involved in or around vehicle tracking
and parking lot management. Only a few of these showed at least some similarities in function and design. Each
of these patents is outlined below with a brief abstract as taken from the U.S. Trademark and Patent Office.
U.S. PAT. NO. 4,568,937
1
Induction loop vehicle detector
Filed: June 2, 1983
Abstract:
An induction loop vehicle detector comprises an oscillator circuit having a plurality of capacitors
switchable in circuit with a road loop under the control of a microcomputer to determine the oscillator
frequency. The microcomputer monitors the oscillator frequency and controls the switching of the
capacitors to periodically return the frequency to a predetermined value. A counter counts a
predetermined number of oscillator cycles and gates of h.f. clock into a second counter whereby the count
of the counter represents the oscillator period. A "vehicle detected" output is given when the monitored
frequency alters by more than a predetermined amount, representing a decrease in the inductance of the
loop. On detecting an increase in the inductance above a predetermined threshold the detector is inhibited
for a predetermined time, e.g. about 1 second, to avoid errors caused by magnetic effects.
Key Claims:
A vehicle detector comprising: an oscillator circuit having capacitance means arranged to be connected to
a road loop for determining the frequency of the oscillator circuit; means for monitoring the frequency of
said oscillator circuit; a control processor arranged to control the capacitance of the capacitance means so
as to periodically return the frequency to a predetermined value; detector means for producing an output
signal indicative of a detected vehicle when the monitored frequency alters by more than a predetermined
amount, said detector means detecting a decrease in the inductance of the road loop and in response
thereto for providing a signal indicative of the presence of a vehicle; means for detecting an increase in the
inductance above a predetermined threshold; and means, responsive to said means for detecting, for
inhibiting the detector means for a predetermined time after detecting said increase in the inductance.
U.S. PAT. NO. 5,910,782
2
On-board vehicle parking space finder service
[1] Clark, Induction Loop Vehicle Detector, Available:
http://www.ptodirect.com/Results/Patents?query=PN/4568937, (1983)
[2] Schmitt and Buchalo, On-board vehicle parking space finder service, Available:
http://www.freepatentsonline.com/5910782.html, (1999)

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Filed: June 8, 1999
Abstract:
An on-board vehicle navigation system parking space finder that offers a driver a competitive edge in
finding available on-street parking. Drivers not familiar with an area are able to locate available metered
parking spaces with ease. Drivers may be informed, on demand, of what type of currency they need for
parking meters in certain areas, so they can stop for change, if necessary. Drivers will have information
about maximum time limits for different parking meters, and can use this information to select meters
with longer time limits, if necessary. Metered parking information specific to a vehicles current location, as
well as metered parking information specific to a requested location, is made optionally available to
drivers from within their vehicles.
Key Claims:
receiving a driver request to initiate a parking availability request; transmitting the parking availability
request over a wireless medium to a central site; receiving a response message representative of current
parking availability information in a geographic area from the central site, the central site collecting
parking availability information transmitted from sensor devices monitoring associated parking spaces,
said parking spaces comprising at least one on-street parking space;
U.S. PAT. NO. 4,943,805
3
Conduit-enclosed induction loop for a vehicle detector
Filed: July 24, 1990
Abstract:
An induction loop and a method of making an induction loop having conduit sections connected by a
coupling assembly. The coupling assembly includes a passageway-defining body having ends for receiving
sections of conduit. An intermediate body portion includes an opening exposing an intermediate
passageway exteriorly. A lid for sealingly [sic] covering the opening includes an extension placeable [sic]
into the opening for mating engagement with corresponding wall portions of the coupling body. The body
and lid provide lateral external-pressure-withstanding structure to prevent damage to the assembled loop
by absorbing regional pressures. This structure also provides for internal-pressure-withstanding sealing
between the two so that, after completion of insertion of conductor in the conduit loop, the conduit may
be injected under increased pressure with a heated rubberized asphalt sealant which is flexible at ambient
conditions. Flexible joints in the form of short flexible conduit portions are inserted between the coupling
[3] Dennison, Conduit-Enclosed Induction Loop for a Vehicle Detector, Available:
http://www.ptodirect.com/Results/Patents?query=PN/4568937, (1990)

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body and the relatively rigid conduit section to permit angular displacement of the body relative to the
section.
Key Claims:
1. In an inductive loop vehicle detector having a conductor extending in a loop-shaped conduit: a
conductor-surrounding filler within said conduit; and a conduit coupling assembly joining sections of the
conduit comprising: a body defining (a) a passageway extending through said body sized to receive at
each end of said passageway an end of a section of conduit, and (b) an opening externally exposing a
portion of said passageway intermediate its ends, said opening being defined by a wall portion extending
continuously about said opening; and a lid sized to completely cover said opening and having a continuous
loop-forming extension matingly [sic] engaging said continuous wall portion when said lid is covering said
opening; and said continuous extension and wall portion being mutually adherable [sic] for sealing said
opening; said conductor-surrounding filler filling said coupling assembly; and an adhesive adhering said
continuous extension and said wall portion together.
2.2.3 ANALYSIS OF PATENT LIABILITY
While these listed patents are similar in nature to our project we do vary in a few ways which might constitute a
counter argument to a patent violation suit. First listed, the patent for the vehicle tracker using inductions loops
itself is the same but instead of measuring the frequency directly for changes as well as having the frequency
computer controlled, E.S.P is using an envelope detector to convert alterations in the oscillation frequency to a
voltage level and measure it using a microcontroller.
When compared to the most recent patent, the airport radar tracking system is dissimilar in the detection
methods, purpose and scope of the project but the general idea was similar enough to warrant a closer inspection.
Fortunately, this patent is for aircraft parking lots, also called Aprons, and will be to track aircraft on the ground at
an airport and thus is dissimilar enough to our project in which we will not have any conflict.
Additionally, the thesis product will be using mobile copper wire loops tapped together for demonstration and
prototype purposes only. Actual construction and installation would be done by cutting a trench in the concrete
and laying the wire with a concrete road sealant on top.

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2.2.4 ACTION RECOMMENDED
To best avoid and mitigate patent litigation for the E.S.P. project, maintaining the scope of potential customers is a
must - an automobile parking lot detection and information distribution device. Furthermore the current
detection methods must be kept, as well as the digital controls, in order to prevent infringement upon the first
listed patent which uses several methods to measure and control equipment frequency.
2.2.5 SUMMARY
After an extensive patent search, the design team concluded that the particular method for tracking vehicles and
the service provided through a computer system to display the tracking information is a unique product and if
remaining in scope of the previously established proposal and should not subject this team or the project to any
patent litigation
2.3 PROBLEM FORMULATION
Considering the dire need for improved parking at UNO, team E.S.P. decided it was of upmost importance to
develop a new method to aid the university. By hearing complaints via word of mouth, personal experience as well
as using hard statistics provided by the parking office this issue at hand is justified and the goal to provide a
working vehicle detection system is very realistic. The statistical analysis provided by the university was derived
from a study conducted in the spring of 2011 on the parking and shuttle system on campus. The details of this
report are not authorized for public release but this data was critical in conceptualizing the underlying issue and
the causes.
Additionally, a survey for the student body and faculty/staff was created but ultimately not pursued based of the
amount of approval required to send a mass email to the entire campus and collect data.
Though several tests run throughout the semester the project will be easy to verify through data. As an extended
effort to provide a reliable system for users to use, one of the project specific success criteria is just that, to be at
least 99% accurate at detecting when a vehicle enters or exits a lot.

20
Final Report
3.0 PROJECT DESIGN REQUIREMENTS, SPECIFICATIONS AND SUCCESS CRITERIA
3.1 INTRODUCTION
This project from its conception was to build on a set of design objectives. These objectives best described the
goals of our project and how we would design our product and subsequently directed the criteria the team set
forth to determine project success. These success criteria were divided into two groups, Project Common Success
Criteria (PCSCs), goals for which any project in the CEEN department must meet and Project Specific Success
Criteria (PSSCs). These PSSCs were first proposed by the team in the fall semester of 2011 and approved by the
Senior Project Office, Professor Herb Detloff and deal with specific projects attributes.
The only alteration to these PSSCs was made on January 23
rd
, 2012 on an approved Engineering Charge Request
(E.C.R.) which can be found in Appendix B for reference.

Project Proposal
21
3.2 OBJECTIVE TREE
Figure 5 - Objective Tree
3.3 PROJECT COMMON SUCCESS CRITERIA
PCSC Description
Bill of Materials Create a complete bill of materials and order/sample all parts needed for the design
Schematic Develop a complete, accurate, readable schematic of the design. Include interface loading
and timing analysis.
PCB Complete a layout and etch a printed circuit board
Assembly Populate and debug the design on a custom printed circuit board
Package Professionally package the finished product and demonstrate its functionality
Figure 6 - PCSC Listing

22
Final Report
3.4 PROJECT SPECIFIC SUCCESS CRITERIA
Marketing
Requirement
PSSC Description
1, 4 Accuracy The tracker will be able to accurately detect 99 out of 100 cars upon
entering and exiting the parking lot – proven by testing.
2,3,4 Mobile access Client will be accessible via web browser on personal computers, iOS,
and Android via web browser.
1 Reliability Local node keeps master count of lot traffic and can be retrieved by
the server at any time. Users receive accurate lot count via browser
upon refresh within 1 minute.
1,2 BIT testing System will check for component failure by using built in diagnostic
tools every 30 minutes and display errors to administrator login on
website.
1 IEEE Standard System Communication will meet communication standards for
Ethernet (IEEE 802.3)
System communication will adhere to packet and frame formatting
standards as outlined in IEEE 802.3 chapter 3.
Marketing Requirements
1 - System is reliable
2 - System is easy to use
3 - System is low cost
4 - System is adaptable
Figure 7 - PSSC Listing

Project Proposal
23
3.5 DELIVERABLES
As a result of our project we will present the following deliverables:
• A tracker that can detect when a vehicle enters or exits a parking lot.
• The server on which the data will be stored will be able to handle input from multiple sources.
• The data on the server will be accessible through the local network.
3.6 CONSTRAINTS
Through the course of the project we will have the following constraints:
• Have a 99% accuracy or better detection rate of cars
• Withstand precipitation – i.e. rainproof
• If student funded, the cost of this project must be under $1,500
• If funded by UNO, this project will remain within our established budget
• Information must have accessibility through the local network
• Reliable during school hours
• Local node will be powered by 120V, 60Hz
• System cannot be attached to the vehicles, system must be discrete (ex: no Infrared tags on vehicle
pass)
• Project must be completed by the end of the semester

24
Final Report
4.0 CONCEPT DEVELOPMENT, SYNTHESIS AND PROCESS DESCRIPTION
This section details the process by which the team developed concepts and methods to solve the identified
problem of find a parking space on campus. As a guide, the Senior Thesis textbook was used for several templates
and concept generation and reduction techniques.
4
4.1 LITERATURE REVIEW
To understand the environment and the constraints dictated by the problem extensive research was done on
possible solutions and currently available technology in order to perform the most basic functions of our system.
The primary vehicle for research started at both personal experiences of each team member as well as internet
searches using the Google search engine. From this several white papers, studies, and presentations were
obtained from several specific companies that offer solutions to track a vehicle and the Department of
Transportation (DOT). The study by the DOT
5
was actually the most beneficial document as it provided scientific
and technical background data for which to make well informed decisions on current technology.
4.2 CONCEPT GENERATION
As a result of the research conducted into possible and current solutions the team began to determine concepts of
operation how a possible system might work. However the first decision required was to determine if it would be
better to track the number of cars entering the parking lot or to track every individual space in the parking lot. This
was ultimately narrowed using a simple pro and con list shown below. Once the scope was specified to where the
project was going to detect the vehicles that gave the team a specific direction to go when generating solution
methods.
[4] Ford and Caulston, Design for Electrical and Computer Engineers, 2008.
[5] Federal Highway Adminstration, ”Sensor Technology", Traffic Detector Handbook, Available:
www.fhwa.dot.gov/publications/research/operations/its/06108/02.cfm

Project Proposal
25
Method Strengths Weaknesses
Whole Lot Tracker Decreased Cost
Centralized equipment
Minimal construction
Accuracy might be questionable
Implementation becomes questionable in
non-standard lots
Differentiation may be questionable
Individual Space
Tracker
Near Absolute accuracy
Able to locate individual empty spaces
Doesn’t need to differentiate between
cars/motorcycles
Hundreds of trackers per lot
Significantly Increased Cost
Requires power at every space
May be damaged by snow plows
Figure 8 - Tracker Implementation Comparison
4.3 CONCEPT REDUCTION
The following diagrams show our analysis of determining the methods of detection and system communication.
Depending on the desired information we used either a Strength and Weakness Comparison chart or a Weighted
Pairwise Comparison to make our decision.
The next table shows the strengths and weaknesses comparison of all of the possible concepts generated in an
attempt to help eliminate some of the least probably solutions.
Tracking Method Local Node Communication Method
Tracker/Node
Communication Method
Node/Server
Display
Method
Laser Detection Full PC Ethernet Ethernet Marquee
Induction Loops Microcontroller Zigbee Zigbee Website
Image Recognition WiFi WiFi Cell App
Ultrasonic
Detection
Laser
RFID
RADAR
Integrated
Figure 9 – Methods Table

26
Final Report
The next table takes each PSSC and uses a Pairwise Comparison method to weight each requirement in relation to
the others.
Method Strengths Weaknesses
Laser Detection Easy to implement
Cheap
Provides a simple on/off interface
Easily triggered by pedestrians
Visible
Small range of detection
Induction Loops Good detection of vehicles
Low error rate
Unseen
Underground construction
Expensive
Image Recognition High detection rate
Vehicle differentiation
Processing heavy
Difficult implementation
Ultrasonic Detection Easy to implement
Cheap
Wide area of detection
Does not work well with distance
Human interference
RADAR Very large scan area
Reliable
Expensive
Very complex data processing
RFID Small footprint
Easy to implement
Simple high/low trigger input
Too costly to implement for all students
Requires separate entity for student or on
student car
Short read distance
Full PC Large processing power
Ease of use
Bulky
Needs to be weatherproof
Microcontroller Only Small
Could be concealed
Cheap
Limited abilities
Ethernet Fast
Cheap
Common
Physical interface
Distance issues
Zigbee Cheap
Small
Distance efficient
Interference and obstructions
WiFi Easy to incorporate
Standard, already available on
campus
Distance issues
Speed and congestion issues
Integrated Small package
Less hardware
Needs stronger node/server
communication
Marquee Easy to see
Convenient to traffic
Big
Expensive
Website Common
Easy to use
Easily available
-
Cell App Extremely easy to access
Gives users on demand info
Software heavy
Stress on servers for data requests
Figure 10 - Pros / Cons Table

Project Proposal
27
Accuracy
Installation
Availability
Application
Portability
Price
Application
Visibility
Weatherproof
Safety
Mean Weight
Accuracy 1 5 3 3 5 3 1/3 1/5 1.61 0.13
Installation 1/5 1 1/3 1/3 1 1/3 1/5 1/5 0.36 0.03
Availability 1/3 3 1 3 3 1 1/5 1/7 0.84 0.07
Application
Portability
1/3 3 1/3 1 3 1 1/7 1/7 0.61 0.05
Price 1/5 1 1/3 1/3 1 1/3 1/7 1/9 0.32 0.03
Application Visibility 1/3 3 1 1 3 1 1/5 1/7 0.74 0.06
Weatherproof 3 5 5 5 7 5 1 1/3 2.85 0.23
Safety 5 5 7 7 9 9 3 1 4.83 0.40
Total 12.17 1.00
Figure 11 - Pairwise Comparison
Lastly, the list of Detection Methods shown in previous figures with the weighted values obtained above were used
in the following table to generate a value system to show which detection method meets our engineering
requirements the best.
Figure 12 – Decision Chart
Image
Processing
Inductance
Loops
Laser
Tripwire RADAR RFID Tags
Controlled
Gates
Accuracy 0.13
5 3 1/3 3 5 7
Mechanical
Complexity
0.03
3 3 7 1/7 1/3 1
Availability 0.07
Application
Portability
0.05
5 3 1/5 3 1/3 1
Price 0.03
3 3 5 1/5 1/3 1/7
Application
Visibility
0.06
5 3 1/7 3 7 7
Weatherproof 0.23 5 5 1 5 5 1/3
Safety 0.4 5 7 1/7 7 7 1/3
Score 4.743 4.121 1.026 3.766 4.649 3.352

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Final Report
By the above analysis the best solution to our problem is Image Processing followed by RFID Tags and Inductance
Loops. After examining each of those options, Image Processing requires more powerful computers than a
microcontroller and the RFID tags have a very short range and aren’t practical in vehicle situations without major
construction and impeding the traffic flow. This ultimately let the team to design and build a system based off of
induction loops as the method for detecting vehicles.
Research into how to make an induction loop was derived from several textbooks which described how to design
various oscillators.
6 7
[6] Beasley and Miller, Laboratory Manual to Accompany Modern Electronic Communications, 9th
Ed., 2008.
[7] Jaeger and Blalock, Microelectronic Circuit Design, 3rd Ed., 2008.

Project Proposal
29
4.4 PROJECT SCHEDULE
Figure 13 – Project Schedule

30
Final Report
This Page is Intentionally Blank

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31
5.0 DETAILED ENGINEERING ANALYSIS AND DESIGN PRODUCT PRESENTATION
5.1 ENGINEERING ANALYSIS
In order for vehicle detection to reliably work, much research was done to find the best possible solution to fit the
University’s need. As can be shown in the previous section, induction loops were determined to be the most cost
effective and reliable solution.
The first order of design was the oscillator, as a stable frequency is required. Several designs were simulated and
built on a bread board but were unsuccessful since they were not stable. Some of those designs were as follows:
Figure 14 - Concept Design 1
Figure 15 - Concept Design 2

32
Final Report
The final circuit design consists of a stable Colpitts Oscillator going to a low pass filter to avoid any sidebands and
finally to an envelope detector to be able to read a stable DC value at the output.
To design for each of the 4 frequency oscillators needed, the following equation was used:
𝐶1 = 𝐶2 =
𝐿𝑜𝑜𝑝 𝐼𝑛𝑑𝑢𝑐𝑡𝑎𝑛𝑐𝑒
(2𝜋 ∗ 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦)2
When the loop inductance was measured to be 83µH and with the desired frequencies: 60kHz, 70kHz, 80kHz, and
90kHz the capacitors were able to adjust to fit appropriately. To determine the size and shape of the loops used,
the equation from the United States Department of Transportation Report
8
was used:
[8] United States Department of Transportation Report, Available:
http://www.dot.gov/about.html
Figure 16 - Final Tracker Design

Project Proposal
33
𝐼𝑛𝑑𝑢𝑐𝑡𝑎𝑛𝑐𝑒 =
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑡𝑢𝑟𝑛𝑠 ∗ 𝑀𝑎𝑔𝑛𝑒𝑡𝑖𝑐 𝐹𝑙𝑢𝑥 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 ∗ 𝐶𝑟𝑜𝑠𝑠 𝑆𝑒𝑐𝑡𝑖𝑜𝑛𝑎𝑙 𝐴𝑟𝑒𝑎
𝐶𝑜𝑖𝑙 𝐶𝑢𝑟𝑟𝑒𝑛𝑡
So just by looking at this equation, one can see that if there are a constant number of turns, same size of area, and
constant current, that any change to the magnetic field will alter the inductance which in turn will alter the
frequency of the oscillator. After filtering out the sidebands, the envelope detector was the last important step as
a stable DC output is required. The envelop detector was simulated individually to test for minimal oscillation
amplitude and acceptable decay rate from high to low frequency states.
To further demonstrate the ability of this circuit design, it was prototyped on a bread board and several testing
measurements were taken. The figure below shows the circuit laid on the bread board for testing.
Figure 18 - Envelope Detector Circuit Figure 17 - Envelope Detector Simulation
Figure 19 - Tracker Circuit Prototype

34
Final Report
Used a testing platform, an induction loop was built inside of a PVC pipe frame to provide project testing a
constant shape and configuration for a consistent inductance value. Figure 20 shows the 6 pass induction loop in
PVC pipe used for lab testing standing on its side as to avoid any magnetic field due to the steel beams in building’s
the floor.
Figure 22 shows the frequency
and voltage at the standing
position to be 2.9V at 68kHz.
Figure 21 shows the loop on
the ground with a metal shelf
in the middle to cause a
magnetic disturbance.
And finally, Figure 23 shows the
impact of the cart and the
voltage to now be 1.7V at
72kHz successfully
demonstrating the analog
inductance loop detector
circuit as designed.
The next logical step for the detector was to find an enclosure that would be able to operate in outdoor weather
and be big enough to fit the entire PCB and cables inside. The following document was completed as an in depth
analysis of the different types of packaging available to use.
Figure 22 - PVC Induction Loop (1) Figure 20 - PVC Induction Loop (2)
Figure 23 - Tracker Circuit Prototype Waveforms (No Car) Figure 21- Tracker Circuit Prototype Waveforms (Simulated Car)

Project Proposal
35
5.2 PRODUCT PRESENTATION
5.2.1 INTRODUCTION – PACKAGING DESCRIPTION
The Efficient Student Parking (E.S.P.) project is to develop a vehicle detection system that will monitor up to four
complete induction loops using Colpitts oscillators and band pass filters to detect vehicles based on frequency
shifts. Due to the operating environment this system would need to operate in, the project needs to have very
specific packing requirements to operate safely and effectively without impeding the flow of traffic.
5.2.2 COMMERCIAL PRODUCT PACKAGING
The concept of tracking vehicles with inductive loops is not a unique concept and as such the E.S.P. project has
several commercially available products which perform similar functions and thus can provide good examples for
which to compare our team’s design. Two of these particular products are from Sen Source and their TC-BL44
Series Inductive Burial Loop Vehicle Counter and Marsh Products Inc. 610 Loop Vehicle Detector. Both of these
products use induction loops to detect vehicles and are packaged to meeting environmental conditions similar to
those set forth in our project proposal.
5.2.2.1 MARSH PRODUCTS 610 LOOP VEHICLE DETECTOR9
This product is packaged in a durable ABS plastic which is sealed and secured
using metal screws. The enclosure is secured to a frame using mounting
screws or a Velcro strap. The casing is designed with a temperature rating of
-40 degrees Fahrenheit to 180 degrees Fahrenheit.
The advantage of this product’s packaging is it makes the device completely
enclosed with signaling LED’s to view status information of the detector. The
one thing this product does not account for is the external communications
port on the right side is not covered for rain or other environmental effects.
[9] Marsh Products Inc, 610 Loop Vehicle Detector, Available:
http://www.marshproducts.com/pdf/LoopVehicle.pdf
Figure 24 - 610 Loop Vehicle Detector

36
Final Report
This product also boasts a UL approved Class 2 Plug-in the wall 12 VDC adapter and connected via screw terminals.
5.2.2.2 SEN SOURCE TC-2BL44-R INDUCTIVE BURIAL LOOP VEHICLE COUNTER10
The Sen Source product line has different product for single and dual
lane counting devices. Each of these are enclosed in a similar casing
that is adapted to meet the needs of their customers.
This enclosure is a 5.1” by 5.1” by 3” case rated at NEMA4x
standards. The casing is made of a polycarbonate material and
secured using lock tight screws. Some of their other products which
include similar functionality that the E.S.P. project is demonstrating
are enclosed in a large casing that is 9.5” by 11.25” by 7”. For
reference, the National Electric Code (NEC) lists the specific
requirements for standards such as NEMA 4x and are located in
Appendix D. The real significant of this product is that not only were
they the only company of the two to cite a specific standards specification on the enclosure but that the
specification was so rigid. Initially the team was examining NEMA 3R rated metal enclosures for cost reasons but
after analyzing the Sen Source products the NEMA 4x enclosure seemed to be a product standard we should strive
to meet if funding permits.
5.2.3 PROJECT PACKAGING SPECIFICATIONS
The field equipment used in the E.S.P. project will consist of a single fiberglass
enclosure which meets NEMA 4x standard for outdoor electrical protection. An
AMU1084CCHF from FactoryMation
11
was selected for use in our project which
features a 10” x 8” x 4” area with a polycarbonate window and hinged screw
cover which will be good for presentation and display of functionality. A
finished market product could utilize a solid cover just the same. On the
[10] Sensource, "Inductive Burial Loop Vehicle Counter", Available: http://vehicle-
counters.com/PDF/TC-BL44-R-2BL44-R.pdf
[11] FactoryMation,
Available:http://www.factorymation.com/s.nl/it.A/id.4754/.f?sc=2&category=16831
Figure 26. AMU1084CCHF
10"x8"x4" fiberglass enclosure
Figure 25 - TC-2BL44-R Inductive Burial Loop
Vehicle Counter

Project Proposal
37
product webpage it is listed as being suitable for applications such as “Electrical and electronic controls,
instruments, components” and meets several specifications which are beneficial in outdoor settings which are
listed in the table below:
Mounting screws and all objects which penetrate the enclosure will be
sealed with weatherproof sealant or similar glue or epoxy to maintain
environmental ratings. Ideally, if funding permits, the enclosure has
an associated subpanel standoff which allows for equipment
mounting while maintaining the integrity of the enclosure. The case
itself will be mounted to a wooden 4” x 4” post using ¾” plywood
backing to mount on as the screw holes are 6-1/2” apart.
All cables which will enter into the enclosure will be contained within
½” Liquid Tight Flexible Metal Conduit (LFMC) for the prototype but
for a professional market installation typical Rigid Metal Conduit
(RMC) or Rigid Nonmetallic Conduit (RNMC) may be used in
accordance with local and national electrical standards. All conduit
connections will only demonstrate the connection type for the
prototype and thus will only extend roughly a foot from the enclosure.
Additionally, as any mounting screws and other penetrations into the
enclosure, proper precautions, connections and sealant will be used to
connect the conduit body to the enclosure.
Power connections will be made using three AWG#16 THHN wire to energize an internal NEMA 5-15R power
receptacle such as a Leviton 5320-WCP12
from Platt.com. This power receptacle will be enclosed in its own
junction box similar to the Appleton 4CS-1/213
which is 4” x 2-1/8” x 1-7/8”. This junction box will be capped with
[12] Available: http://www.platt.com/platt-electric-supply/Residential-Receptacles-15-Amp-
Duplex/Leviton/5320-WCP/product.aspx?zpid=265848
[13] Available: http://www.platt.com/platt-electric-supply/Handy-Boxes-Accessories-
Boxes/Appleton/4CS-1-2/product.aspx?zpid=205793
NEMA 4X Specifications
Non-corrosive
Non-conductive
Temperature-resistant
Fire-resistant
Rated NEMA 4, 4X, 12
UL listed Type 1, 2, 3, 3R, 4, 4X, 12, 13
Figure 27 - NEMA 4X Specifications

38
Final Report
a faceplate similar to an Appleton 251014
to maintain a safe working environment when the project is de-
energized.
[14] Available: http://www.platt.com/platt-electric-supply/Handy-Boxes-Accessories-Box-
Covers/Appleton/2510/product.aspx?zpid=231183
Figure 29. Appleton 2510 Duplex CoverFigure 30 - Appleton 4CS-1-2 Figure 28 - 5-15R

Project Proposal
39
5.2.4 PCB FOOTPRINT LAYOUT
The PCB layout for this project will be a closely packed circuit board that will require several outside connections,
such as power, the external inductance loops, Ethernet connection and the LCD/marquee display. The PCB layout
without any routing or a silk screen can be found in figure 37 on page 48. The most recent design, version 1.7
which is based off of the version 0.7 schematics, is laid out on a 5” by 6” board.
The main consideration from this PCB design is ensuring there will be enough space inside the enclosure to install a
NEMA 5-15R outlet to power our project. This method is a simple way of allowing us to use a simple Wall Wart
power supply for the PCB and plug it directly into a typical 120VAC 15A outlet which removes the need for
installing an isolation transformer and power supply of our own.
Additionally, the orientation of the components and the PCB was a consideration as much as reasonably possible
with our project having so many external connections outside of the enclosure. While not every connection could
have been lined up along one edge of the board, the most important ones to leave the enclosure in the shortest
distance would be the induction loop wires while the power cable and Ethernet connection will have no trouble
being routed around the enclosure.

40
Final Report
5.2.5 CAD SCHEMATICS AND ILLUSTRATIONS
Figure 3131 – Enclosure Dimensions

Project Proposal
41
5.2.6 MATERIALS REQUIREMENT
Item Name Description Order Location Price Number Total Cost
AMU1084CCHF Allied Enclosure 10x8x4
NEMA 4X, hinged,
fiberglass.
Factorymation.com $66.00 1 $66.00
P108 Allied Enclosure, steel-
white finish subpanel for
AM1086
Factorymation.com $8.00 1 $8.00
Appleton 2510 Duplex Receptacle Platt.com $0.52 1 $0.52
Appleton 4CS-1/2 4”x2-1/8” J Box Platt.com $1.54 1 $1.54
Leviton 5320-WCP NEMA 5-15R Platt.com $0.70 1 $0.70
½” LFMC Liquid Tight Flexible Metal
Conduit
Stayonline.com $1.35/ft 10 $13.50
3512RAC ½” Metallic Conduit Fitting Stayonline.com $2.50 6 $15.00
3/4x4x8 Pine
Plywood
Lowes.com $29.97 1 $29.97
4x4x8 Douglas-Fir Lowes.com $10.12 1 $10.12
Redwood Exterior
Wood Stain
1-Gallon latex Lowes.com $9.97 1 $9.97
Total $155.32
Figure 3232 – Enclosure Materials
5.2.7 TOOLS REQUIREMENT
Drill Press
Cordless Drill
Plastic Drill Bits
Wood Drill Bits
Screwdriver
Adjustable Wrench
Circular Saw with minimum 4” blade
Paint Brush
Weatherproof Epoxy or Hot Glue Gun

42
Final Report
5.2.8 ESTIMATED WEIGHT
AMU1084CCHF Fiberglass Enclosure, 6 lb
5-15R and Enclosure, 1 lb
Electrical Components, 1 lb
1’ EMT (x6) with couplers, 1 lb
Total Weight 8 lb
5.3 HARDWARE DESIGN
After the selection of the casing, the project advanced onto designing the digital circuitry to ensure it has sufficient
communication and requirements to handle all of the incoming and outgoing data.
5.3.1 INTRODUCTION – HARDWARE DESIGN REVIEW
The Efficient Student Parking (E.S.P.) project is to develop a vehicle detection system that will monitor up to four
complete induction loops using Colpitts oscillators and low pass filters to detect vehicles based on frequency shifts.
Circuit design also consists of a 40 pin microcontroller, LCD, an Ethernet controller for communication, and outputs
available for future expansion via XBee.
5.3.2 THEORY OF OPERATION
The most critical functionality lies within the operation of the oscillator and band pass filter to yield successful
voltage readings when cars pass over the loops. Each Colpitts oscillator is designed to oscillate at different
frequencies 60 kHz, 70 kHz, 80 kHz, and 90 kHz since they will be close range to each other and will help reduce
noise. Following the oscillator, the signal goes into a low pass filter where it is actively filtered to the designed
frequency and is tunable via a potentiometer.
Logically, when a car passes over the loop it will shift the frequency of the oscillator and thus drastically reduce the
output voltage of the band pass filter. Lastly, the output of the filter goes into an envelope detector to get a near
constant peak voltage reading which will be used in the microcontroller ADC for measurements. Components for
these circuits were chosen to be all 1% resistor and 5% capacitor tolerances with a quad package high precision
low noise op-amp for the filtering for the best accuracy. In order to have the filters function properly they require
both a positive and a negative 5VDC power rail. The positive 5VDC and 3.3VDC power rails are taken care of via

Project Proposal
43
basic voltage regulators (LD1085 and LD111733 respectively) but the negative rail is a special case, as the circuit
only takes in a positive DC value, and will be accomplished using the MAX764CPA. Both the oscillator and low pass
output from all four loops will be routed to a test point for ease of access for troubleshooting.
Following the envelope detector, the signal goes into one of the microcontrollers ADC ports for digital analysis.
Once this input is converted into a decimal value, it will have a programmable threshold value it will test against
which will determine the sensitivity of vehicle detection. Upon successful detection, the controller will format the
positive trigger as a command package and send it over the Ethernet via the Lantronix Xport to the server and
database. Another small component that will provide helpful data, read in through the ADC, is the MCP9700
temperature sensor to monitor ambient temperature to be sure the device is operating within the acceptable
range.
5.3.3 HARDWARE DESIGN NARRATIVE
The Atmega1284p is a powerful microcontroller that provides all of the functionality that E.S.P. requires for the
parking local node. Since there are 32 general I/O pins, the following paragraphs will break down how each port is
used and why it was chosen for that usage.
Easily using the most pin space on the controller is the 20 X 4 character LCD which will be
demonstrating the marquee functionality. As data is transmitted in 8 bit parallel, it requires
a full port dedication for communication. Nothing in the E.S.P. design requires any data
transfer over I²C so PORTC was decided to be used as the data port, seen in figure 35.
Associated pins for LCD enable and register select are PORTD pin 7 and PORTD pin 6
respectively. There is an additional pins on the LCD for Read/Write ability but was grounded
as it will never be need to be read from, as well as a contrast pot which will be available on
board. One thing to note, the connector on the PCB is actually a mirror image of the actual LCD connector as it will
be connected via ribbon cable which mirrors the pins on the other end.
One of the interior subsystems in the Atmega1284p that will be seeing a lot of action is the USART (universal
synchronous/asynchronous receiver/transmitter). As the gateway to the server from the local node, it will be in
constant communication sending and receiving commands and will have a
high priority, second only to the ADC readings. The most important thing
that was needed to take into consideration when connecting the USART
was to make sure to cross over the connection between Rx and Tx from
Figure 33 – Data Ports
Figure 34 – Logic Converters

44
Final Report
the controller to the Ethernet controller to ensure correct data flow. Having the ability to add a future XBee also
affects the design as most XBee models do not have 5VDC I/O serial pins. Due to this issue, logic translators have
been incorporated between the USART and XBee data pins that convert the CMOS 5VDC logic of the Atmega to
3.3VDC logic of the XBee and vice versa using the Texas Instruments TXB0101 one bit bidirectional voltage level
translator. Shown above in figure 34 are the two logic converters for both Tx and Rx.
The only other major subsystem used in the microcontroller is the analog to digital channels by each of the four
induction loops and temperature sensor. Every 300 to 500milliesonds each ADC channel will check the voltage and
compare it to the threshold value to determine if a car is present. Internally, the ADC will be used in the trigger
fashion by checking the ADC interrupt flag and clearing it after it is read. Using free running mode would also be
possible but leaves room for error when needing to be read from and the value is not ready. Even though the
temperature sensor will always be outputting a voltage linear to the temperature, it will only be checked when the
server sends a testing command or if in maintenance mode (menu option). All commands will be read in through
the Ethernet controller to the USART character by character and will be handled by a USART parsing function.
Exterior to the controller will be three hardware buttons which will allow for access to a software menu. Having
this ability lets a user choose between several options such as: marquee display mode, maintenance mode –
displays loop voltages and temperature, and lot management – allows for local changes to the lot count via
up/down buttons. The casing will be needed to be opened up to have access to these on board buttons.
Lastly, programmability will lie within using the AVR ISP programmer and standard 6 pin ICSP connector. The
programming is done over the SPI bus and is the only device that will be using this serial connection. Going to a
block connector are the rest of the 8 general I/O pins that are not used as well as the 4 loop outputs that can be
used for any voltage measurements. There is also a 6 pin block connector for 3.3VDC, 5VDC, and GND which can be
used for testing purposes.
5.3.4 SUMMARY
As this hardware review comes to a close, it can be seen that the E.S.P. hardware has been clearly described and
outlined above. To summarize, the main components are the Atmega controller, Lantronix Xport controller, and
the induction loop circuits. Along with the hardware needs comes the controller subsystems and software
including: ADC channels, USARTs, menu system, and full port access for LCD. Special consideration was taken for
each device to be sure it was powered by the correct voltage level as well as the data pin tolerance and voltage
swing allowed. To briefly reiterate, the microcontroller uses 5VDC, filter op-amp uses 5VDC and -5VDC, and the
Xport will be using 3.3VDC; all devices are 5VDC tolerant.

Project Proposal
45
5.3.5 SCHEMATIC
Attached on the next page is the entire set of hardware schematics for the E.S.P. project. All components follow
IEEE standard 91-1984
15
with the only exception being bidirectional signals. Below, in figure 3, is a basic overview
of data flow and power of the hardware.
[15] Texas Instruments Explanation of Logic Symbols [Online]. Available:
http://www.ti.com/lit/ml/sdyz001a/sdyz001a.pdf ,1996.
Figure 35 – Atmega Functional Flow Chart

46
Final Report
5.4 PCB DESIGN
5.4.1 INTRODUCTION – PCB DESIGN
The Efficient Student Parking (E.S.P.) project is to develop a vehicle detection system on a single printed circuit
board (PCB) to be enclosed at a single location near the parking lot. Using a single board design requires
considerations for the following issues: component spacing, heat dissipation, design flow placement, and trace
width and size. Team E.S.P. will draw PCB design techniques from previous experience and instructor suggestions
to design a complete working circuit board.
5.4.2 PCB LAYOUT DESIGN CONSIDERATIONS - OVERALL
The PCB design for E.S.P. will be a total of 30 in² (5” x 6”) and will contain all components needed, including the
Ethernet controller and loop oscillator circuits. The biggest factor of the PCB design layout is the placement of the
components. Components are laid out on the board in order of signal flow
and ease of use. For example, one can see in the figure to the right that all
components relating to the loop circuits are located on the bottom middle
part of the board, all resistor values are located in the same order for all 4
loops, and each potentiometer is conveniently located in a clutter free
area for easy access. This allows for anyone using the equipment to not
only find what they are looking for quickly but also allows for a better
understanding of how that section of components are working. In the case
of the loops, it is a priority that the inductance loops are not interfered
with by any on board noise and therefore are placed at the very edge. This also applies to the maintenance
buttons located conveniently at the top of the board as well as the ISP programmer pins located at the top to
prevent the programmer dangling over the entire board. There are also test points to allow for much more
convenient access to important parts of the analog signals for testing than as they would be by trying to have a volt
meter on the right of the board on an unmarked soldered pin. Lastly, both the power and Ethernet connections are
located on the left side of the board for ease of access.
Figure 36 – Image of Project PCB

Project Proposal
47
For all component signal traces, the standard 10 mil trace width will be used and will be routed with 15 mil trace
spacing. According to the millhouse at Advanced Circuits
16
these specifications are well within those required to
make a PCB. All other specifications used at Advanced Circuits such as silkscreen text width, board size and
thickness, and drill hole/pad size will be followed to ensure a successful PCB is created. One large PCB design
concern is the Ethernet controller and the heat dissipation required by the device. Special consideration is given to
it by having a 1 square inch top and bottom ground plane around the device connecting both of its shield pins to
ensure that the device does not overheat when transferring large amounts of data at a high rate.
A consideration was given to the size of the board versus the amount of space needed for traces concluding with
using mostly through-hole components as fewer vias were needed and traces could be routed more efficiently
without components on both sides of the board.
5.4.3 PCB LAYOUT DESIGN CONSIDERATIONS - MICROCONTROLLER
The microcontroller, Atmega1284, is a 40 pin through-hole microcontroller that is powered by 5 VDC and controls
all logic components in the project. Due to this fact, the Atmega is placed very close to the middle of the board to
help prevent any signals from being extremely far from the controller. Clocking is accomplished using the crystal
oscillator method with a 16kHz crystal connected to the x1 and x2 pins of the µC. These circuit components are
placed very close to the actual controller as the further away they are the noisier the clock signal will be.
There are also two separate voltage inputs for the microcontroller; one is the analog voltage input. Each of these
voltage/ground pairs has a 100 nF bypass capacitor from +5VDC to ground to eliminate any EMI or voltage spikes
and are placed as close to the Atmega as physically possible. The AVCC also has a ferrite bead going to +5VDC to
help separate the digital versus analog supply voltages. Ground between the two has also been considered and will
only be connected at one point via a solder-able connector, seen on the PCB layout in Appendix A at the top right
of the board. Having only a single point of connection greatly cuts down on the chance of creating a ground loop
between the power/analog/digital grounds. This 100nF bypass cap strategy has also been followed throughout all
the rest of the digital components: XBee, Xport, and -5VDC regulator.
[16] Advanced Circuits ,PCB Design Specifications [Online], Available: http://4pcb.com/pcb-
design-specifications/, 2007.

48
Final Report
5.4.4 PCB LAYOUT DESIGN CONSIDERATIONS – POWER SUPPLY
All components need power in some form or another so the method of delivery of power is a very important
design factor. Due to this fact and the concept that these traces will be the ones to help to dissipate heat leads to
the idea of thicker board traces for the power and ground lines. The size of these traces has been decided to be at
least 25mil thick as it has been demonstrated to be successful in the past on several occasions. The idea was
considered to have a dedicated layer for both power and ground but resolved to be too much of an extraneous
expense since it is not required for the board to have 4 layers. Another thing to note is the layout of the power
circuitry – located on the left side of the PCB. The local node board will get its source of power from a standard
7.5V 1A wall wart via a DC jack on the PCB. This will then be fed into the 5VDC and -5VDC regulators going to the
majority of the chips. The 3.3VDC power rail will be sourced out of the 5VDC regulator to help conserve on the
voltage drop and reduce the heat on the 3.3V regulator. In another attempt to reduce heat from the 3.3V
regulator, since it will be sourcing quite a bit of current for the Ethernet controller, will be to have a small ground
plane around it.
5.4.5 SUMMARY
In summary, the Efficient Student Parking lot tracker is a compact single PCB package that will perform all logic
calculations on board and have the ability to communicate via Ethernet to a central server. Signal width and traces
were taken into consideration and sized and routed accordingly to have the optimal data transfer. Power and
ground traces and width were also considered and were designed to be bigger than the signal traces as to help
dissipate more heat and are routed as to not couple with the signal traces. Again, to help with voltage spikes and
EMI, bypass capacitors were placed as close to the digital devices as possible. Lastly, it was made sure to have
mounting screws on each of the 4 corners to allow for the board to be mounted inside of the NEMA 4X case.

Project Proposal
49
5.4.6 PCB LAYOUT
Figure 37 – PCB Schematic
Finally finishing the hardware design and physical board design we moved onto the embedded software for the
E.S.P. local node. The following document goes into a deeper explanation of how we incorporated our software
design into the hardware and server.

50
Final Report
5.5 FIRMWARE LISTING
5.5.1 INTRODUCTION
The goal of Efficient Student Parking (E.S.P) is to develop a vehicle detection system that allows people to see an
accurate representation of parking availability. Of the different components that make up this project, each relies
heavily on the use of software for communication and automation. The microcontroller on the local node will
detect vehicles enter and exiting the parking lot as well as communicate with the server. The local node will be
programmed using an AVR programmer and will be coded in embedded C.
The server will interface with users, administrators, and the local node. This will run as a desktop application and
will be programmed in Java. Finally, the client will interface with the server. It will run as an embedded Java applet
and will be embedded in the web page.
5.5.2 SOFTWARE DESIGN NARRATIVE
The code on the microcontroller is separated into different display modes. The functionality of this is to display the
information in real time to the LCD of the board. During these states, the board will still be able to detect cars via
interrupts triggered by the ADC. This code has been thoroughly tested and is sitting at a 100% success rate.
The board will also be able to send any messages to the server through the USART and Ethernet. This is checked
repeatedly in each state as communication is a very high priority. Messages needing to be sent are stored in a
buffer within the Xport module and wait until the microcontroller is ready to process them. The Xport is a very
convenient module as it is very “black box” in terms of the programming. All configurations were completed using
a telnet interface such as speed of data transfer, IP address, and USART data modes.
The server consists of 3 modules: the main console, the Ethernet/communication module, and the
database/logging module. The main console initiates the Graphical User Interface (GUI) and sets up the entire
configuration needed for Ethernet communication. All data is routed through the main console, while the other
modules either run on separate threads or are called at some point in the main console.
The Ethernet/communication module is isolated in its own specific process, or thread. This module constantly
listens for messages from the local node. This is important, as the communication and GUI need to run in parallel -
to keep the GUI from hanging and the communication module from missing messages. When data is received, it
sends a message to the main console containing the parsed data, which is then formatted and logged.

Senior Thesis - ESP - Final

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