Final Report
Self Monitoring Parking Meter
December 3rd, 2009
Prepared for
Mr. August Allo University of Texas at San Antonio 6900 N. Loop 1604 West San Antonio, TX 78249 (210) 458-7753 (210) 458-5947 (Fax)
Prepared by
Design Team #7 David SanchezRaul G. RamosJoshua TorreyJesus Luna
Table of Contents1.0 Executive Summary.........................................................................................................................5
2.0 Introduction.....................................................................................................................................6
3.0 Need Being Addressed.....................................................................................................................8
4.0 Literature and Patent Search Results...............................................................................................9
5.0 Marketing Analysis and Market Strategy.........................................................................................9
5.1 Market Need................................................................................................................................9
5.2 Segmented Target Markets.......................................................................................................10
5.2.1 Universities........................................................................................................................10
5.2.2 Cities..................................................................................................................................10
5.2.3 Parking Garages.................................................................................................................11
5.3 Market Growth..........................................................................................................................11
6.0 Engineering Design Constraints.....................................................................................................11
6.1 Global Constraints.....................................................................................................................11
6.2 Local Constraints........................................................................................................................12
7.0 User Requirements........................................................................................................................13
8.0 Engineering Codes and Standards.................................................................................................14
9.0 Design Concepts............................................................................................................................15
10.0 Product Specifications...................................................................................................................18
10.1 User Specifications.....................................................................................................................18
10.2 Hardware Specifications............................................................................................................19
11.0 Operational Scenarios....................................................................................................................20
11.0.1 Proper Operation...................................................................................................................20
11.0.2 Improper Operation...............................................................................................................20
12.0 High Level Block Diagram...............................................................................................................21
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13.0 Major (Critical) Components..........................................................................................................22
13.1 Microcontroller – Arduino Mega...............................................................................................22
13.2 XBee Module.............................................................................................................................23
13.3 Ultrasonic Sensor.......................................................................................................................23
13.4 Graphical User Interface (GUI)...................................................................................................25
14.0 Detailed Design..........................................................................................................................25
14.1 Hardware...................................................................................................................................25
14.1.1 Microcontroller..................................................................................................................25
14.1.2 Wireless Modules..............................................................................................................26
14.1.3 Ultrasonic Sensor...............................................................................................................27
14.1.4 Push Button........................................................................................................................27
14.2 Software....................................................................................................................................27
14.2.1 Microcontroller Programming..........................................................................................27
14.2.2 GUI Programming..............................................................................................................29
14.3 Engineering Analysis and Calculations...........................................................................................32
14.3.1 Ultrasonic Sensor Calculations...........................................................................................32
14.3.2 GUI Calculations.................................................................................................................33
15.0 Major Problems.............................................................................................................................35
16.0 Integration and Implementation...................................................................................................36
16.1 Integration.................................................................................................................................36
16.1.1 Preparation Phase..............................................................................................................37
16.1.2 Design Phase......................................................................................................................37
16.1.3 Testing Phase.....................................................................................................................38
16.1.4 Completion Phase..............................................................................................................38
16.2 Implementation.............................................................................................................................38
16.2.1 Ultrasonic Sensor...............................................................................................................38
16.2.2 Arduino Mega....................................................................................................................39
16.2.3 Arduino Mega and Ultrasonic Sensor Communication......................................................39
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16.2.4 XBee Communication.........................................................................................................39
16.2.5 Arduino Board, Ultrasonic Sensor and XBee Modules Communication.............................40
16.2.6 Push Button........................................................................................................................40
16.2.7 LED Display.........................................................................................................................41
16.2.8 Graphical User Interface (GUI)...........................................................................................42
17.0 Comments and Conclusion............................................................................................................43
18.0 Team Members..............................................................................................................................44
18.0.1 Joshua Torrey.........................................................................................................................44
18.0.2 Raul G. Ramos........................................................................................................................44
18.0.3 David Sanchez........................................................................................................................44
18.0.4 Jesus Luna..............................................................................................................................45
19.0 References.....................................................................................................................................45
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1.0 Executive SummaryTeam Seven of the Senior Design II course has developed a system that provides real
time information of parking spaces throughout parking lots. The purpose of this project was to
design a more efficient system of parking meter enforcement to replace the extremely out of date
current system with today’s technology to make this task more efficient. Furthermore, the new
design will feature a system of parking meters that automatically detect illegally parked vehicles,
and alert the violation to a base station in which the officers would be present. Additionally, a
Graphical User Interface (GUI) would provide the results from the base station to handheld
devices to notify patrolling officers of any illegally used parking spaces. The result? Large
metropolitan areas require less manpower and resources to maintain their current parking
locations. For the purpose of this project, the vehicle detection phase incorporated an ultrasonic
sensor. This was decided upon after reviewing budget constraints of all team members. The
small ultrasonic sensors are less expensive and provide a proof-of-concept model that could be
significantly upgraded with better sensor equipment. In an effort to simulate the functionality of
a parking meter, a push button was integrated into the design to simulate a coin deposit. In terms
of hardware, a microcontroller was implemented to acquire both the sensor and push button
input, it also controls which states the parking space is in. In conclusion, the system includes
wireless communication between the data acquired by the parking meter and the base station, so
no long cables were necessary for this system. According to the original proposal submitted by
Team Seven, a team composed of four Electrical Engineering senior students, the description
above was included and targeted to be finished in mid November. Figure 1 illustrates the final
design.
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Figure 1 Final Design
2.0 Introduction Parking station monitoring has become a larger priority as the economy pulls people
closer to their jobs and cities. Proper use of these Parking Stations is both helpful to the citizens
who wish to use them and also to the companies that have invested in building them. Similarly,
cities are looking for ways to increase revenue without once again increasing the fee amount per
traffic fine. Reducing the number of unaccounted violations and fine challenges remains the
largest area of financial growth to be obtained. With this in mind, the concept of a new
monitoring parking station should reduce illegal parking while increasing parking violation
profits.
In preparation for this proposal, market analysis and user design needs were considered in
developing a hard-list of design requirements. These requirements helped form the necessary
design constraints for the design process of the Parking Meter. Other tasks such as patent
searches, design alternatives and block diagrams helped formulate a cohesive top-level view of
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the design in preparation for a detailed design analysis. These tasks provided much of the
material and information contained in this proposal.
Each team member provided a key asset to the design of the parking meter. With each
member of the team capable of handling unique portions of the design, no single member was
called upon to deliver more than the others. This resulted in an efficient and productive schedule
as well as completion of all deliverables. David Sanchez provided DSP experience to both the
ADC & DAC development of the design. Furthermore, Mr. Sanchez was in charge of all the
documentation required for the team. Raul Ramos utilized his Matlab and Controls experience
to develop the Graphical User Interface (GUI). Mr. Ramos also served as the administrative
portion of the design. Joshua Torrey made use of his professional Computer Design and
Programming experience in coding the microcontroller, he also was in charge of the website
development for the group. Likewise, Jesus Luna had knowledge in computer programming and
made a strong positive impact to the microcontroller interfacing. The detailed view of the
schedule will be shown on Figure 2.
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3.0 Need Being AddressedIn recent years, parking has become a serious problem under the increase of motor
vehicles. A new monitoring system for parking meters is needed for today’s transportation
system. The current system of parking meter enforcement consists of several parking officers
manually checking each meter, trying to catch illegally parked vehicles. The new parking meter
system would be marketed to large metropolitan areas for example: Universities, Cities, and
Parking Garages. They all have different mechanisms to which the system was implemented. In
universities and cities the new system will improve the quality of how officers will receive
information of any illegally parked vehicles. Reducing labor time and improving parker
convenience are the main focuses to implement this new system.
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Figure 2 Team Schedule for Self Monitoring Parking Meter
4.0 Literature and Patent Search ResultsIn the early stages of the project, Engineering Standards and current patents/technologies
were researched to consider what was already in the field. Most applications of car detection
were in regards to parking facilities with monitoring at the entrance or exits or the generic
vehicle detection at a stoplight. In both of these cases, induction coils are placed in the cement,
which is both costly, and not in a position to produce direct financial benefits. However the
application of this new system is in a field of substantial profit. Taking advantage of this,
different types of implemented sensors are capable of being positioned individually in each
space. It at this point that the entire system of the project exceeds and of the patent information
researched. Another process that was taken into consideration is the system utilized by
automobiles RFID tags, which uses ultrasonic sensors to acquire data of any close objects one
might be approaching. Use of RFID tags is safely within all Engineering Standards and RFID
tags are found in many different patented technologies. However in that model, instead of the
sensor moving, the sensor is placed statically and when the presence of a car is detected it sends
a signal to the system. This model is more effective for garage monitoring and not open location
parking system (downtown, schools, etc).
5.0 Marketing Analysis and Market StrategyThe new parking meter system would be marketed to highly populated areas, including
but not limited to Universities, Cities, and Parking Garages. Each market would utilize the
current design idea in the way most profitable to their existing circumstances. In Universities and
Cities the new system would improve the speed at which officers are alerted of illegally parked
vehicles. This reduces the amount of paid labor hours while improving the correct usage of
parking space, both major factors in the implementation of this new system. In Parking Garages,
the system would be used solely for the purpose of relaying available parking locations to
incoming vehicles.
5.1 Market Need
Parking meters are a key element in both the transportation market and a cities’ citation
revenue. With respect to transportation, there are limited numbers of parking spaces available in
every metropolitan area, and they are frequently in high demand by users. Development of a new
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parking meter system increased the precision of detecting any illegally parked vehicles and
provides better access for those willing to pay for the spots. With respect to citation revenue,
cities across the United States have slowly been increasing the citation fees for illegal parking. It
has become a viable source of increase in revenue. With this new design, cities were capable of
again increasing their citation revenue without increasing parking fees. Along with these
increases in fees, the increase in citations challenged has also gone up. These challenges result
in consistently lost revenue through the legal system. This new parking detection system would
provide the cities with a reliable, consistent, and overwhelming case against such challenges,
seeking to neutralize them and further increase the revenue collected.
5.2 Segmented Target MarketsThe market strategy targeted:
5.2.1 UniversitiesThe improved system can be implemented on any withstanding university parking meter
system. This simple detection system along with passing notification to the limited patrolmen
makes the system perfect for campus use.
Servicing the parking needs of large campuses has been one of the biggest challenges
facing universities as the number of students seeking parking spaces continues to rise.
Universities have slowly utilized park and pay stations for several years now. This system would
allow more Universities to confidently include additional park and pay stations.
5.2.2 CitiesFor cities, the improved system will work seamlessly with both older and modern parking
meters. Parking has implications on business viability, economic development, public safety and
quality of life for metropolitan residents. It is also an integral part of the city's land use and
transportation initiatives. Effective parking management is a key issue in determining the vitality
of a city.
The current system has drawbacks of being manually operated, non-uniformly controlled
and inefficient in terms of revenue collection and control. Patrolmen currently cover all parking
locations, serving as the cities form of parking meter enforcement. The new system is based
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upon a more competent means of doing the same enforcement. This will lead to more revenue
and better quality public service for all participating cities.
5.2.3 Parking GaragesThe updated system can also be incorporated to parking garages. Since the new system
will give real time feedback to a base computer, it can provide real time information to the
vehicles entering the parking garage, allowing them to see available parking spaces that are
conveniently close and vacant.
With the growing demand for parking garages where small area and high efficiency are
needed, an improved system for the users of these parking garages will need to be developed.
5.3 Market GrowthMetropolitan areas are experiencing exponential growth as the economy once again
brings people closer to where they work. This city growth will increase the demand for more
effectively monitored parking spaces. It was anticipated that a demand for our product will
increase as communities seek to cut-down on expenses. Furthermore, the demand for this
product was not limited by the bounds of the U.S. market. The market range of this product
consists of any city in the world facing the need for more parking location efficiency. Different
laws will be applied in different markets towards the use of our product, but should represent no
loss in demand since this system was cost effective and precise. This product will market itself
once incorporated.
6.0 Engineering Design ConstraintsThere were many factors that were considered in the design process of the Self
Monitoring Parking Meter. The team considered two types of constraints which are global and
local. Listed below are the subsections of these constraints.
6.1 Global Constraints Economic Factors
The economic constraint applied to this system because the total cost was limited due
to a lack of funding. The final product would also benefit the marketed buyer in
increasing their revenue.
Environmental EffectsTeam #7 Electrical Engineering Design 2 Page 11
This constraint did not apply to this system since we are utilizing sensors that do not
interfere with the environment. For communication the system utilized wireless
modules so no need for long cables is required.
Sustainability
The system was affected by this constraint since there are a fixed number of parking
meters. The market will increase as this new parking is implemented in large
metropolitan areas.
Manufacturability
The Self Monitoring Parking Meter was not a constraint by this since the system
requires few electronic components; this should not be a complex manufacturing
process.
Ethical Consideration
The constraint should not apply to this system due to the fact that it provides the
required data to know all the parking violations.
Health & Safety
The constraint should apply in the manufacturing stage of the system. Likewise the
disposal of electronic components required stringent exposure requirements but the
use of the product was not created health or safety issues.
Social Ramification
The product was constrained in a positive way since it encouraged the proper parking
procedure from citizens therefore it will be beneficial effects on society.
Political Factors
The increase of parking fines with this new system was not a good political campaign
throughout the different states.
Legal Issues
Currently the status quo does not infringe on any patents and the idea for the product is
already patented. A careful design procedure was limited by the legal issues this
product incurred but the potential is there.
6.2 Local Constraints Cost
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The cost was constrained to this system because the cost cannot exceed the budget
received for production. There was currently no ability to raise capital for this project.
Schedule
This project was constrained by schedule because the team must have a working
prototype to demonstrate at the end of the Senior Design II course.
Manufacturability
This system was constrained by the limited amount of hands-on skills that the team
members have acquired throughout their careers.
Engineering codes and standards
The product has abided by all codes & standards when in use. The team modified any
steps required to meet all standards.
Ethical considerations
Even as students under UTSA’s Senior Design program, this does not bring ethical
issues for the students or the university.
Health and safety issues
The team member’s and user’s safety was an important constraint in the system.
Lead-free solder and adopting other RoHS standards during the manufacturing stage of
the system helped avoid any minimal impact on this constraint.
Legal
There are no legal issues that stems from the production of the system. It was
important that the system was properly tested to reduce any chance of being liable.
7.0 User RequirementsThe Self-monitoring parking meter was designed to meet many user requirements. Listed
in the subsection below are those user requirements incorporated in the design.
1. The user must be able to read accurate data from each parking space.
2. The user must be able to reset the system from the parking location.
3. The user must be able to deactivate the system for servicing.
4. The user must be able to reset the device in case of accidental readings.
5. The device must have an easily replaceable backup power.
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6. The device must not stand out in any way out of the ordinary.
7. The device must be easy to install to existing fixtures.
8. The system must communicate wirelessly.
9. The system must not interfere with any other frequencies in the ambient.
10. The device must be able to power to a 100~127V @60 Hz supply source in North
America.
11. The device must be able to power to a 220~240 V @50 Hz supply in rest of the world.
12. The software must provide a user-friendly graphical interface.
13. The device must provide real-time status information.
14. The device must be weather-resistant to endure changing weather conditions.
15. The sensor must be enclosed within the parking meter to prevent vandalism.
16. The wireless module antenna must protrude the parking meter for best performance.
17. The system must conform to FCC regulations for wireless communications.
18. The system must require little maintenance.
19. The system must be expandable and customizable.
20. No custom parts should be used to construct the system.
21. The system must be able to recalibrate on its own.
22. The system must be reliable.
8.0 Engineering Codes and StandardsThe design was developed to conform to all applicable engineering codes and standards.
Below is a list of the engineering standards referenced for the project:
IEEE Standard 802.15.4-2006
Description
This IEEE standard specifies the physical layer and media access control (MAC) for low-rate
wireless personal area network1.
Type
Regulatory Standard
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Conforming Components
XBee wireless modules
Restriction of Hazardous Substances Directive (RoHS)
Description
RoHS is often referred to as the lead-free directive, but it restricts the quantity used to
create a device by setting a maximum concentration within the following six substances:
Hexavalent chromium (1,000 ppm max)
Poly-brominated biphenyls (1,000 ppm max)
Poly-brominated diphenyl ethers (1,000 ppm max)
Cadmium (100 ppm max)
Mercury (1,000 ppm max)
Lead (1,000 ppm max)
Type
European Union Regulatory Standard
Conforming Components
XBee wireless modules
7-Segment Serial Display
Ultrasonic Range Finder – Maxbotix LV EZ1
XBee Breakout Board
9.0 Design ConceptsThe design idea involved developing an upgrade to or replacement for the current parking
meter system that can detect when a vehicle was illegally parked. In the current detection phase
an ultrasonic sensor was considered as it was the cheapest technological option. When the
detection circuit senses an illegally parked car, the parking location monitor where the violation
occurred transmits to a computer based network station. The central computer acting as the home
network would contain real time data of any illegal parking and would be available at all times.
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This home network would also retain previous violation information to help monitor and track
trouble locations.
The first concept considered was a wireless network consisting of a base computer and
varying quantity of parking location monitors (transmitters). Parking location monitors, using
ultrasonic sensor, were to be an addition to current parking meters. Handheld devices consisted
of original design and software similar to that on the base computer.
The second concept considered was a wired network consisting of a base computer, and a
varying quantity of parking location monitors. Parking location monitors, using ultrasonic
sensor, were to be an addition to current parking meters. All parking notification information was
reported via walkie-talkies, removing the need for wireless handheld devices.
The third concept considered was an entirely digital, and wireless, network designed from
the ground up at the parking meter phase; consisting of a base computer, a varying quantity of
parking location monitors (transmitters), and multiple handheld patrol devices (receivers).
Parking location monitors, using ultrasonic sensor, were to be an addition to current parking
meters.
For this matrix, the highest weight factors are attributed to Cost, Schedule, and Effective
Range. Effective Range was considered the essential constraint given the natural market usage of
our current design idea. Our design idea seeks to cover, efficiently, the most parking locations
(area) possible. Cost and Schedule was also important constraints on us as students with only one
semester to construct our design. After these constraints; Convenience, Resistance to Weather
and Conforming to Engineering Standards are the next highest weighted. Convenience of Usage
helped reduce the number of patrolmen needed to monitor all parking locations. Resistance to
Weather considers the effect weather could have on the efficiency of our violation data transfer
and on the physical structure of our design devices. Communication Interference, Complexity,
Product Implementation, Power Consumption and Sustainability rounded out the lower half of
our constraints, yet measure the marketability of the current design idea. However, they do not
apply as strongly to the current design idea in view of a Senior Design Project’s parameters. In
comparison, the Wired and Wireless Upgrade designs were the most highly rated. The Cost and
Schedule factors highlighted ease and low-cost of the Wired System Design. Convenience of
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Usage heavily favored our Wireless Upgrade design while Resistance to Weather supported the
Wired Upgrade design. The Pugh Matrix is illustrated in Figure 3.
Pugh Matrix
Design Constraint
Weight
Factor Design 1 Design 2 Design 3
Cost 11 7 10 4
Effective Range 11 9 5 9
Resistant To Weather 10 8 10 8
Communication Interference 8 8 10 8
Complexity 5 7 8 5
Conform To Eng. Code & Stand. 10 10 10 10
Product Implementation 8 7 8 6
Power Consumption 8 7 8 9
Convenience Of Usage 10 10 6 10
Sustainability 7 8 5 9
Schedule 12 7 9 4
Total 100 807 816 743
Figure 3 Pugh Matrix
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Ultimately, the matrix valued both the Wireless and Wired Upgrade Options similarly.
For the purpose of this class the team decided to move forward with the Wireless Upgrade
Option, as it was the option that best displayed our design skills.
10.0 Product SpecificationsThe system design consists of a few market-required components that are critical to
provide excellent functionality and sustain marketability. By evaluating the multiple markets the
system seeks to reach, the team compiled a list of all requirements. The ones deemed most
important are discussed in detail within their proper field.
10.1 User SpecificationsWireless Communication:
Description:
The system should be capable of handling wireless communication from multiple parking
locations to a main hub station.
Criticality:
A reliance on wires or other physical constructs make the design inapplicable to cities
and schools where underground laying of required transfer equipment is unacceptable.
Technical Issues:
Wireless communication modules are required within every location-monitoring package.
This increases the total cost to monitor each location.
PDA/Handheld GUI:
Description:
The system should provide accurate and up to date information on all monitored locations
in an easy to read GUI. This GUI should be capable of being run on a Handheld or PDA device.
Criticality:
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To allow for proper violation documentation, as well as reduce the need for patrol
officers in the field, the GUI must satisfy all information needs required for the city or university
to write up a violation without risk/fear of legal liability.
Technical Issues:
GUI based writing for multiple platforms is a complicated and tedious process. For this
design, a Simulink example has been designed to show what the GUI would need to provide for
in-field use.
10.2 Hardware SpecificationsCompatibility with Analog & Digital Parking Meters:
Description:
Given the many forms of parking meters, the system should be capable of being infused
with any current parking meter system. This includes analog and digital individual park meters
as well as large pay station meters that are becoming popular.
Criticality:
Being able to reach every technological market of the parking meter industry is essential
for good marketability and sustainability.
Technical Issues:
Since all modern parking meters are digital in nature, the system is designed to handle
digital inputs. For analog systems, most contain or simplify down to digital signals at some point
in the system and are easily feasible.
Sensor Upgrades:
Description:
Providing multiple sensor options to allow for cost control abilities to users.
Criticality:
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The ability to provide users with multiple detection sensor methods is essential in
reaching the many different types of coverage units required. Allowing users to reduce cost or
improve power efficiency provides the user satisfaction needed to sustain sales.
Technical Issues:
The system design is capable of handling all sensor input. It is the microcontroller code
that must be unique to each sensor input. This code can easily be changed and set for each sensor
type made available.
11.0 Operational ScenariosThe Self Monitoring Parking Meter is a device that assists parking meter patrol officers
and makes their checks more efficient. Even though this design was mainly conceived to be used
with motor vehicle parking meters, the same concept can be applied to other uses. A very close
application would be to monitor boat dock spaces or arrivals at the many harbors throughout the
world. Even though this other application would require a different platform, in essence it would
incorporate the same concept used in our design
11.0.1 Proper OperationThe parking meter notification system works by detecting the presence of a vehicle
within a parking space and relaying the status wirelessly to patrol officers. Making such
information readily available increases the efficiency of checking meters and the ease of parking
for patrons. The design uses wireless modules to relay the status information to a central main
station but also has the potential to be sent to mobile computer devices mostly used by patrol
officers.
11.0.2 Improper Operation Given that the design depends entirely on an ultrasonic sensor to detect the presence of a
vehicle, vandalism may affect the design’s performance and operation. Should there be an
intentional obstruction of the sensor the design will no longer provide a reliable stream of
information. In that scenario, the information would not accurately depict the parking status
thereby corrupting the wireless communication data. In addition, a weather-proof ultrasonic
sensor would need to be installed to prevent corrupt data transmission due to weather damage.
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12.0 High Level Block DiagramDuring the process of selection, the team proposed different design ideas and different
ways of implementing each of those ideas. Several of these ideas were discarded based on
important weighting factors such as cost and time required. Therefore after careful examination
of the multiple feasible concepts generated by the Pugh Matrix, the team decided that the best
conceptual design approach and most realizable option would be the one presented in Figure 4.
Figure 4 Block Diagram
The team spent the summer doing research on the electronic components, selecting those
components that best meet the needs and budget of the design team. A vital task over the
summer was to develop familiarity with the major components that comprise the project in order
to understand their strengths and weaknesses.
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13.0 Major (Critical) Components The components required for the parking meter monitoring system included a
microcontroller, two wireless XBee modules, and ultrasonic sensor for parking location
simulation, LED display and system GUI. Parts were chosen based upon proven capability, cost
efficiency and ease of use.
13.1 Microcontroller – Arduino MegaTeam Seven had initially proposed to purchase the HCS12 Dragon12-Plus but after
further research and advice from a team member experienced with the Arduino Duemilanove, the
team decided to order an Arduino. Arduino provided the sufficient features for the design as well
as the cheap price versus the HCS12 Dragon12-Plus. After deciding to go with the Arduino, two
distinct microcontrollers were considered for the project, the Duemilanove and the Mega as
shown in Figure 5. Given that the team was unsure if additional components were going to be
added as the semester progressed, the Arduino Mega was chosen over the Duemilanove because
of its increased quantity of I/O pins.
Figure 5 Arduino Mega and Duemilanove
The Arduino board provides16 analog input pins, 54 digital I/O pins of which 14 can be
used for PWM outputs. The design relies on the use of PIN 7 of the PWM section of the board
for compatibility with the ultrasonic sensor in order to output a pulse. This application allows
the use of the Pulse Width Modulation (PWM) option. The power levels necessary to power all
electronic components are provided by the Arduino Mega’s 3.3V/5V power pins, which are both
convenient and simplistic. With no need to build a separate voltage regulator circuit to provide
power, both money and time were saved for other portions of the design. In regards to the
Arduino programming, there were many online examples to help accomplish needed sections of
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the design. Some examples were exact models of needed code and others were adequate
examples. A good example was the pushbutton program that was found on the Arduino website.
The final great feature was the ability to power the Arduino Mega with a single 9V battery to
avoid using AC power adapter for showcase purposes.
13.2 XBee ModuleThe XBee modules were chosen for their plug and utilize ability. Furthermore, this was
the primary reason for determining its implementation in the design. Few elements of the
module required set up; establishing one Xbee as a Base and another as a Remote, both
advantageous and simplistic. On the technical side, the Vcc supply powering one the XBee was
from the Arduino Mega’s 3.3V power pin. The Dout, Din and GND pins on that XBee are
connected to the RX, TX and GND pins on the Arduino Mega respectively. The standard
breakout board for the XBee pin outs, as shown in Figure 6, was the exact board used on for the
design. The second XBee must remain attached to the USB development board connected to the
GUI computer, which acts as the necessary power supply, and process the A/D conversions from
signals received from the XBee.
Figure 6 XBee pins
13.3 Ultrasonic SensorAn ultrasonic sensor and an induction coil were the two major object detection
components proposed. After carefully considering the advice of Mr. Ramos to use a Maxbotix
ultrasonic sensor over an induction coil, it was decided that the sensor was easier to implement
onto the SMP Meter and also five times cheaper than an induction coil. Two distinct ultrasonic
sensors were considered for the project, the non-weather resistant LV-EZ1 and the weather-
resistant LV-WR1 as shown in Figure 7.
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Figure 7 Ultrasonic Sensor
The ultrasonic sensor LV-EZ1 model from Maxbotix contained all the necessary features
for a “proof of concept” design and was four times cheaper than a weather-resistant model. In
functionality it acts as a transceiver both sending and receiving ultrasonic waves. The primary
element of the sensor was the 13 sound waves of a 42 kHz frequency produced by the sensor
when it was turned on (power supply turned high). The Arduino code used for the design set the
supply voltage high to allow a single pulse and then turn the supply low to shut down the sensor.
However in a locked on state, the ultrasonic sensor was capable of producing pulses every 49 ms
for real time detection. The detection area of the sensor was always depicted in cone shaped. An
object at a distance within six inches from the sensor was always displayed as an output value of
six inches regardless of actual distance. Therefore proper usage of the sensor begins past the six
inches mark from sensor. Likewise, upon start up, the sensor performs a calibration step that
requires no object be within 15-20 inches of the sensor.
In order to produce such high frequency waves from electrical energy, an ultrasonic
transducer was built within the sensor, which was responsible for emitting the waves. In order to
evaluate the echoes generated by objects the transducer converts from acoustic energy back to
electrical energy. The sensor then calculates the time interval between the sent sound waves and
received echoes to determine the distance to an object. The sensor has a power window of
2.5V~5.5V and an optimal long-range detection distance of 6.45 meters within a 50° angle.
Team #7 Electrical Engineering Design 2 Page 24
13.4 Graphical User Interface (GUI)A user-friendly and easy to use interface platform was needed in the Main Station to
monitor the status of parking meters. The Main Station is the place where the wireless numerical
sequences that contain the status information sent by the Arduino Mega through the XBee
modules would be ultimately analyzed and displayed to the parking officers. The
Matlab/Simulink approach was chosen because of its ease of use, wide range of tools and the
familiarity a team member had with it. In addition, Simulink had a wide range of compatible
serial communication options for the XBee wireless modules. Finally, a key component for using
the Matlab/Simulink package was the extent of documentation both within the software and
online websites.
14.0 Detailed DesignMultiple designs were purposed for the implementation of a self-monitoring parking
system. Different methods required the use of different hardware while all found compatibility
within the software GUI system. Many objectives and requirements were used to influence the
final decision as previously shown via the Pugh Selection Matrix explanation. The final design
was properly displayed and explained in the high level block diagram.
14.1 HardwareFrom the block diagram and from Section 13 (Major Components) it seen that the
hardware contained five components. These five components were the microcontroller, two
wireless XBee modules, ultrasonic sensor, pushbutton for parking location simulation and LED
display. The hardware's intensive utilization (described in detail in Section 13) allows the
simplistic functionality to shine through in this design. Mr. Ramos and Mr. Sanchez were in
charge of all the hardware in the project.
14.1.1 MicrocontrollerThe microcontroller acts as the central detection authority in this design for each parking
location. The microcontroller receives constant feedback from the ultra sonic sensor to correlate
with the current time allowed on the parking meter. The parking meter then sends its parking
location report via the XBee modules to be reported to the main station using the GUI.
Team #7 Electrical Engineering Design 2 Page 25
Jesus Luna led the development and coding for the microcontroller with coding help and
flow advice from Joshua Torrey. As a team, the group analyzed example code from the Arduino
website as well as the unique instruction set supplied in a C like programming language. The
conceptual data reports from the microcontroller to the GUI were derived by Joshua but were
implemented and refined to a usable completion by Raul and Jesus. Jesus modified code to help
the microcontroller control maintain awareness of the current time and likewise the time allotted
for the parking location to provide the backbone of our design.
Table 1provides a brief description of each of the pins used in the design both in relation
to communication and pins essential to the programming of the microcontroller.
Pin # Type Configuration Function(s)
0 Serial UART Input*Receives any information coming from the
Xbee connected to the computer
1 Serial UART Output*Transmits the current state and time left on
the parking meter.
2 Digital Interrupt
*Interrupt is triggered every time the "coin"
button is pressed with a minimum delay of
250 milliseconds between presses
7
Digital Output*Creates square pulse to drive ultrasonic
sensor
Digital Input*Reads if there is bouncing of signal after the
ultrasonic sensor is driven with a square wave
18 Serial UART Output*Sends a binary value to the 7-segment
display that represents the paid time leftTable 1 Pins in the Microcontroller
14.1.2 Wireless ModulesThe XBee modules used for this design were suggested and recommended by Raul
Ramos after gaining experience with them during a summer research program at UTSA. They
were chosen based upon the extremely easy utility and efficiency. The modules essential were
plug and use while providing excellent quality of distance and transmission power given proof of
concept requirements. Mr. Ramos and Mr. Sanchez modified the XBees to ensure that they Team #7 Electrical Engineering Design 2 Page 26
communicate solely with each other.
The XBee modules are the only form of communication within the design. Working in a
pair, one module connected to the microcontroller board while the other connects via a USB
cable to a working computer/base station.
14.1.3 Ultrasonic SensorThe Maxbotix ultrasonic sensors were used for this design as part of the adherence to a
cost efficient project as stated by the Pugh selection matrix. These sensors were capable of
providing sufficiently accurate information for proof of design while also providing excellent
compatibility options with the Arduino board. The sensors are able to supply both digital and
analog reading to the microcontroller with the digital readings being used as the detection
method of this design.
Raul Ramos and David Sanchez tested the sensor and calibrated it. They quantified the
best distance ranges for the sensor as well and noticed trends in the startup calibration of the
sensor.
14.1.4 Push ButtonThe pushbutton used for this design was a part of a pre-packaged bag of extra parts
needed for the design. The button was used as a simplistic time adding mechanism for the timer
simulation part of the design. Jesus Luna wrote the code required to incorporate the pushbutton
into the microcontroller detection system.
14.2 SoftwareSoftware played a critical part both in making the sensor design feasible while also
allowing it to become a system design. Code was used for the Arduino microcontroller while
Matlab/Simulink was used for the GUI to report parking violations. Programming was done and
advised by Joshua Torrey, Jesus Luna and Raul Ramos.
14.2.1 Microcontroller ProgrammingThe microcontroller was programmed through Arduino alpha which acts as a compiler
using Arduino’s own language which was similar to C/C++. The main program follows a set
flow of detection starting with a coin/money check allowing for a time addition or start (in case
of a new car parking), pinging the ultrasonic sensor and processing the result after verify a
vehicle detection (requires seven successful detections) and then determining the time/detection
Team #7 Electrical Engineering Design 2 Page 27
state of the parking location and sending the encoded information serially through the XBee
module.
To incorporate as a realistic simulation, the pushbutton was introduced as a “coin” button
set as an interrupt. Thus, the program stepped out of any current task to increase the paid time
and then returned to the task being processed before the interrupt occurred. For simulation
purposes the time in the parking meter was increased only by 15 seconds each time the button
was pressed. However, this time can be easily modified to a real-life scenario where time is
increased in at least 15 minute intervals.
In order to successfully track time the function millis( ) was used. millis( ) is a function
part of the default Arduino alpha library that returns a value equal to the milliseconds elapsed
from the start of the program. This function was used in several instances of the code; the two
most notorious parts being saving a variable (TimeStart) with a value equal to the one returned
by millis( ) after the first button push, and saving the variable InterruptCurrent which followed
the same procedure as TimeStart but occurred at the beginning of the pushbutton interrupt.
Following are excerpts from the code that demonstrate how millis( ) was used in both instances.
Figure 8 demonstrates how millis( ) was used for the variable TimeStart after a satisfied
condition that checks for a button push and also checks if such button push is the first one to
occur.
Figure 8 Program used for push button and status
Team #7 Electrical Engineering Design 2 Page 28
Figure 9 demonstrates how millis ( ) was used to set the variable InterruptCurrent during
the subroutine that handles the interrupt. The variable InterruptCurrent is used to debounce the
pushbutton because it only sets the CoinFlag if at least one second has elapsed since the last
push.
Figure 9 Interrupt handling
Once the variable TimeStart is set and the number of button pushes is recorded, the
program starts a loop that compares the value of the purchased time with the current time using
the function millis( ). During each loop the code checks with the ultrasonic sensor to ensure a car
is still present. The loop keeps on going and transmitting the information trough the XBee
module until the purchased time is consumed or the parked car leaves the parking space. Once a
new car parks or more time is purchased; the code starts the same procedure.
14.2.2 GUI ProgrammingA Matlab/Simulink software package contained all the tools that the project
required. One of the primary tools used within the package were the communication toolboxes to
establish serial communications. A ‘Query Instrument’ block from the Instrument Control
Toolbox was used to establish COM ports and serial communication between the XBee
development board attached to the computer via USB cable and the Simulink software. Once
established, the numerical sequences enter the Simulink model and are displayed on an ActiveX
numerical LED display. The left-most digit corresponds to a specific parking meter at some
location. The 2nd digit from the left corresponds to the parking meter status which can be
represented by Illegally Parked (0), Legally Parked (1) or No Car Present (2). All digits right of
the parking meter status digit corresponded to the time available on the parking meter.
Team #7 Electrical Engineering Design 2 Page 29
A graphical user interface (GUI) was then designed to communicate with the Simulink
model and provide a user-friendly interface. For this reason, a GUI was needed in the Main
Station to provide a graphical representation of the status of all parking meters to the parking
officers. The GUI was developed using Matlab’s GUIDE wizard to set the window dimension,
the necessary displays, labels, buttons and images on a blank template. After designing the
aesthetic components of the GUI, the next step was to begin programming a pushbutton to
commence the communication process with the Simulink model while another was set to halt the
communication and reset the GUI. The pushbuttons were programmed with functions referred to
as Callbacks. Callbacks are used to acquire set pieces of information by recalling the handles
structure of the block of interest. As an example, the output blocks OUT1 and OUT2 within the
Simulink model are the important since they both contain the information that was read by the
GUI using a handles structure. There are only a few options available when trying to acquire
information from a Simulink block into a GUI. The first option was the use of a function called
RuntimeObject. This allowed the user to acquire a single instance of data by using a Callback
structure but the only problem was that this did not capture data in real-time per our requirement.
After further research, the most viable method was the use of event listeners. In a practical sense,
event listeners can be thought as alarms that only go off when a user-defined event occurs and
then cause a user-defined trigger to perform a specific action. Using the add_exec_event_listener
function, the user is able to add such listeners to specific Simulink blocks as shown in the
example in figure 10 for the output blocks OUT1 and OUT2.
Team #7 Electrical Engineering Design 2 Page 30
Figure 10 Program use for Event Listeners in Matlab
After further coding and testing, the pushbuttons on the GUI were ready to automatically
connect to the Simulink model and begin displaying the information necessary for patrol officers
to perform their duties. The final GUI is shown in figure 11.
Figure 11 Team's Final GUI
Team #7 Electrical Engineering Design 2 Page 31
14.3 Engineering Analysis and CalculationsKnowledge from previous courses helped the team achieve a successful design. The
microcontroller was effectively programmed with all the knowledge acquired during
Microcomputer I and Microcomputer II. Furthermore, Mr. Ramos had utilized this component
during a research program at UTSA which was the main influence to use this component.
Similarly, the analog to digital integration was achieved with the knowledge acquired in Digital
Signal Processing, Signals and Systems I and Signals and Systems II. The Wireless
Communication and Communication Systems classes were helpful for the wireless integration of
the design. Lab 1 and Lab 2 served for all the analog components implemented in the design.
14.3.1 Ultrasonic Sensor CalculationsThe sensor provided two detection methods which provide results in different formats.
The first required the use of analog I/O while the second involved the use of digital I/O. The
latter proved to be the most convenient.
The analog method involved the use of the analog output pin which was labeled as AN
and shown in Figure 10. The sensor has the ability to output an analog voltage-scaling factor that
represents a distance and was calculated by the following formula:
AN=V CC
512
Where Vcc represents the voltage applied to the sensor. As an example, providing 5V to the
sensor the analog output pin AN would provide the following voltage per inch:
AN= 5V512
≈ 9.8 mV /inch
Team #7 Electrical Engineering Design 2 Page 32
Figure 12 Ultrasonic Sensor Pins
The digital method, which was used for the design, takes advantage of the digital TX
(transmit), RX (receive) and PW (pulse width) pins on the sensor as shown in the Figure 12. The
TX pin outputs asynchronous serial data with an RS232 format. The output was an ASCII capital
letter “R” followed by 3 ASCII character digits representing the range calculated by the PW pin
in inches up to a maximum of 255 followed by a carriage return(ASCII 13) or same as hitting the
‘enter key’ on the keyboard. The baud rate, which was the maximum number of symbols per
second transferred was 9600, 8 bits with no parity and a single stop bit. The RX pin was always
pulled HIGH in order to have the sensor continually measure range and pulled LOW if there was
a need to have the EZ-1 stop ranging. The PW pin outputs a pulse width representation of the
range. The PW pin calculates the distance by using the scale factor of 147µs per inch. A pulse
width with duration of 147 µs was equivalent to having an object 1 inch away. As an example, a
pulse with a HIGH duration of 1470 µs represents a distance of 10 inches as shown in Figure 13.
Figure 13 Pulse Width Example
14.3.2 GUI CalculationsThe mathematical algorithm that segments the numerical sequence first needs calculate
the number of digits in the incoming sequence before attempting to separate them accordingly. Team #7 Electrical Engineering Design 2 Page 33
This was accomplished by an Embedded Matlab Function block that contained various formulas
which included the following:
¿of Digits=∫( log (sequence )log (10 )
+1)The int function was used to convert a rational number into an integer. This integer was used to
segment the time available part of the numeric sequence. The use of two additional functions
mod and fix were applied to separate the numeric sequence properly into the ActiveX numeric
LED displays as shown on the right side of Figure 14.
Figure 14 Matlab/Simulink Sequence
A sample of the code within the Embedded Matlab Function block in the Simulink model
and use of the functions described above are shown in Figure 15. The mod function returns the
remainder from the division of two numbers or perhaps described as the modulus after division.
The fix function rounds rational numbers down to zero which yields an array of integers.
Team #7 Electrical Engineering Design 2 Page 34
Figure 15 Matlab code used for Simulink
15.0 Major ProblemsThe first major parking meter simulation problem was polling. The desired outcome of
the microcontroller code was to take into account each button press regardless of input time. This
was a real concern since in use people are allowed to insert money into a parking meter at any
time they desire. However, simply polling the button input pin allowed for some of the inputs to
be lost. The source of this accident was that when an input pin was polled, the input must occur
at the same time the pin was being polled otherwise inputs are ignored. As a solution, the input
pin which was connected to the “coin” button was configured as an interrupt. In this way if an
Team #7 Electrical Engineering Design 2 Page 35
input occurred, the program stopped its current task to take care of the input. It was efficient
programming to reduce the number of possible interrupts but this qualified as a mandatory case.
The second major parking meter simulation problem was switch bouncing. To accurately
model a counter/timer, the microcontroller coded need the counter to be incremented by one each
time the button was pressed. Two unexpected and undesired results however occurred. The first
of which was that after pressing the button, the counter was incremented by more than one. The
second was such that, the switch input was set as an interrupt function where delay functions do
not work. The physical designs of buttons are built in such a way that when they are pressed
there was bouncing (repeated transition between high and low voltage states). This bouncing
may look like a single press for a human because it happens so fast. However a microcontroller
can detect bouncing as several inputs without trouble. Figure 14 illustrates the push button
debouncing.
Figure 16 Push Button Debouncing
Hence the solution was to “debounce” the button pressing. This switch debounce was
done with software. It was necessary to set a “coin” flag inside the interrupt function and then
add a 250 milliseconds delay at the beginning of the code’s main loop (after this delay the “coin”
flag was checked). In this way if the microcontroller detected several inputs only the last one was
taken into account and the counter was incremented by one.
16.0 Integration and Implementation
16.1 IntegrationThe plan provides a detailed description of the methods utilized to achieve all design
objectives. This plan includes all the design phases and how they were integrated into system.
Moreover, the selection and the building of the system implemented. Finally, the testing phase
came to play, to verify that all components worked as planned.Team #7 Electrical Engineering Design 2 Page 36
16.1.1 Preparation PhaseDuring the preparation phase the team studied how the components that were utilized on
the system integrated into the design. Afterward, the group selected and ordered the components
that were implemented on the system. The main components that the group focused on from the
beginning of this design were the microcontroller, ultrasonic sensor, Analog to Digital
Converters and RF signal transceiver. After the components arrived, the team started
incorporating them into the design.
16.1.2 Design PhaseIn the design phase the team started looking for all the alternatives for each major section
of the project. Major components of the design were power, vehicle detection, RF transmitter, and main station design.
16.1.2.1 Power DesignA cohesive power supply design was developed to provide power to every component in
the design. Special attention was given to the power supplied to the Microcontrollers and
wireless transmitter.
16.1.2.2 Vehicle Detection DesignOnce the proper power was supplied to the detection system, an Ultrasonic Sensor
System was developed to provide analog vehicle notification signals as output. At the same time,
an ADC was designed to provide a digital Boolean signal to the microcontroller. The
microcontroller maintained constant analysis of the parking meter. The microcontroller was
programmed in C or C++ to receive these digital signals, analyze them and then provide the
digital signal via wireless communication.
16.1.2.3 Parking Meter RF Transmitter DesignThe RF transceivers were already incorporated to the development board. The team
adjusted the configuration to achieve their signal. Moreover, the development board also
included the Digital to Analog converters for the system to work properly.
16.1.2.4 Main Station Design The Main Station consists of a Matlab/Simulink-based graphical user interface to
provide the officers with a graphical representation of the status of every parking meter. The
Matlab-based GUI can be coded to provide additional viewing options. Such options include
Team #7 Electrical Engineering Design 2 Page 37
allowing the user to instantly view all open, legally filled, illegally filled and soon to be expired
parking stations.
16.1.3 Testing PhaseIn this phase the team began testing each design subsection to verify each worked
accordingly to the design. The team checked that all subsections have the amount of power that
was needed. The ultrasonic sensor design section verified vehicles were properly detected. In the
parking meter design the team verified that the analog to digital converter works properly. The
team verified each component of the system was receiving the proper amount of power to allow
them to operate. The team also tested for any unwanted noise in any of the signals.
Furthermore, the team verified that the wireless transceivers worked properly.
16.1.4 Completion PhaseAfter all testing was completed the team started assembling and completing a working
model of the system. Moreover, the working model was presented to the administration.
Afterwards, the team started making the final revision for the final written report which
described how the process to achieving a fully functional product developed. Finally, the team
prepared a final presentation consisting of the design process. This presentation described all the
functions the system performed.
16.2 ImplementationThe team started implementing each component previously mentioned for the new
system. Each component was run through some testing before it was actually worked
accordingly with the new system. Furthermore, after testing each component for proper
functioning, the team started implementing each component to the specific design.
16.2.1 Ultrasonic SensorBefore the team integrated the ultrasonic sensor the team started testing and calibrating
the sensor. The first thing the team did was to measure its voltage level through an oscilloscope
to observe whether it was working properly. According to the team’s research, the sensor outputs
a scaling factor of Vcc/512. The team used a 3.3 and 5 voltage source to achieve proper reading
in the oscilloscope. The second test for the sensor was to properly calibrate the sensor.
Furthermore, the team tried to achieve this by using a cardboard sheet with a 50 degree angle
drawn onto the cardboard as shown in Figure 17. The only problem was that the team didn’t
Team #7 Electrical Engineering Design 2 Page 38
take into consideration the fact that the detection area would be a three dimensional cone. After
learning this fact, the team solved some issues with the sensor detecting the floor as an object.
Figure 17 Initial Ultrasonic Sensor Calibration
16.2.2 Arduino MegaSince none of the team members were familiar with the Arduino programming, a series
of test programs included in the Arduino’s website were implemented to familiarize the team
with its functions. Furthermore, a program that only integrated a LED light which turned on and
off after pressing the push button helped the team understand general format programming 2.
Likewise, the team became familiar with the serial ports by also utilizing an example in the
Arduino website 3.
16.2.3 Arduino Mega and Ultrasonic Sensor CommunicationAfter the team had properly tested the Arduino board and Ultrasonic sensor they wanted
to make sure that they communicated according to the plan. The team uploaded a program that
detected the distance from a given object and the sensor. This distance appeared in inches and
centimeters and display it in the computer connected through a USB cable from the Arduino
board to a computer. In addition, one can observe a video that clearly illustrates this approach;
the Arduino_and_sensor_communication.mov was included in the project file.
16.2.4 XBee CommunicationFrom the beginning, none of the team members were fully familiar on how the XBee
modules. The XBees included a small development board which facilitated the process of
converting Analog to Digital signals. An illustration on how the XBee and its development board
Team #7 Electrical Engineering Design 2 Page 39
are connected is shown in Figure 18. Soon after the initial research, the team found that the
XBees were supplemented by software known as XCT-U. Moreover, this software included a
test program which let the users know the range in open or close spaces of the modules. The
team started testing the modules in open spaces they had a range of about 100 feet which was
more than enough for the team’s design. In addition, the team also started sending written
messages through these wireless modules.
Figure 18 XBee and Development Board
16.2.5 Arduino Board, Ultrasonic Sensor and XBee Modules CommunicationSince the team had successfully achieved communication between the Arduino
microcontroller and ultrasonic sensor; and between the XBees wireless modules, it was now time
to incorporate all of these components together. The team used the program that had already
being implemented between the Ultrasonic Sensor and Arduino board communication.
Furthermore, this program provided the user with the distance detected by the Ultrasonic Sensor
and illustrates it in the computer connected to the Arduino board. After this major improvement
in the design, it was time to send the information wirelessly. The team integrated the XBee
wireless modules to this program. In addition, the team achieved the wireless communication
between the Arduino board, Ultrasonic Sensor and a base station; which was the final goal for
the team.
16.2.6 Push ButtonThe team integrated a push button to simulate any money deposited into the parking
system. A program which integrated the Arduino board and a push button was found in the
Arduino’s website4. The team incorporated this program into the Arduino board which did not Team #7 Electrical Engineering Design 2 Page 40
work along smoothly with the desired design; these problems were discussed on the major
problems section of this paper. Figure 19 illustrates how the push button was integrated into the
system.
Figure 19 Push Button integrated into the system
16.2.7 LED DisplayThe team decided to implement an LED Display to help the meter user visualize the time
added to the system. This LED display was purchased towards the end of the design since none
of the team members had considered this main component in the design. The team first
considered using separate LED displays for each number in the time sequence. Figure 20
illustrates this approach.
Figure 20 Separate LED displays for each number
Team #7 Electrical Engineering Design 2 Page 41
After careful consideration the team decided to utilize a single LED which was controlled
by one pin instead of thirteen pins. The team started by studying the user manual of the LED
display5. Firstly, a program that would reset LED internal memory was tested. In addition the
team members started controlling the display brightness and set it to its maximum. Finally the
LED display was tested to display several symbol rate values. Figure 21 illustrates the final LED
display applied by the team.
Figure 21 LED Display
16.2.8 Graphical User Interface (GUI)Initially, several test platforms were developed using Matlab’s GUIDE in order to
understand and acquire a basic understanding of how certain GUI components worked.
Pushbuttons, axes and numeric displays were among the first components that were tested. The
tests included pushing a button in order to display set numbers on the numeric LED display,
toggling an LED on and off by pushbuttons and uploading static images onto the axes such as the
UTSA logo. After a basic understanding was obtained, the next step was to program the bottom
left pushbuttons to connect to the GUI with the Simulink model. The initial test platform of the
GUI design for team seven is displayed on Figure 22.
Team #7 Electrical Engineering Design 2 Page 42
Figure 22 First Tests for the GUI
17.0 Comments and ConclusionThis project experience was helpful to all the team members of team seven; it provided a
huge insight of how group projects function. The team clearly understood how each component
was to be integrated and how each member provided some knowledge of their career
concentration. The group decided to have meetings every Monday throughout the semester,
since it was the only day all team members could meet for sure. The team divided some of the
tasks since the beginning of the project. Furthermore, after a person finished their task they were
given a new task or helped a team mate with another job. Initially, the team divided its
responsibilities as their concentration in their Electrical Engineering major. Jesus Luna and
Joshua Torrey were in charge of the functionality of the microcontroller, since they both had
experience on programming. Mr. Torrey was also in charge of the website design. David
Sanchez and Raul Ramos where given the task of integrating the ultrasonic sensor and wireless
modules to the system, since they had experience on signal processing and controls systems
respectively. Moreover, since the wireless and sensor integration did not take as much time as
the team thought these two members were given new responsibilities to continue with the
Design. Raul Ramos was in charge of the GUI design. Mr. Sanchez was responsible for all the
documentation for the project. After all the components worked as they had planned, the Demo
platform was built to start the testing phase of the project. In addition, no major problems
Team #7 Electrical Engineering Design 2 Page 43
occurred from within the group during the Design process. From the start, everybody had a clear
idea of what the final goal was; to finish a great design which will help today’s society.
18.0 Team MembersThis design was developed by a group consisting of four Electrical Engineering students
from the University of Texas at San Antonio. Joshua Torrey, Raul Ramos, David Sanchez, and
Jesus Luna each have fundamental knowledge of electrical engineer. Each member provided a
different area for this design to succeed.
18.0.1 Joshua TorreyJoshua helped with all programming for the group as well as managing the completion of
the final report. His concentration is in Computer Engineering and he has two semesters of
Computer Design & Testing experience with Advanced Micro Devices. Joshua is fluent in both
Perl and C++ while proficient in Ruby, Java and C#. He has taken the following
Programming/Computer Classes: Intro to C, Data Structures, Microcomputer Systems I and
Computer Organization & Design. Mr. Torrey's focus was on providing support for
microcontroller while providing conceptual direction on the GUI for the project.
18.0.2 Raul G. RamosRaul has a Systems and Controls concentration and worked as the hardware integration
team leader. Having taken courses in both control systems and digital signal processing, he
gained experience in Matlab and Simulink which was used to create the team’s GUI. Mr. Ramos
has experience with A/D and D/A converters from his Discrete-Time and Computer Controlled
Systems (EE 4443) along with Neural Networks training and Fuzzy Logic from his current
Intelligent Controls (EE 4733) class. He also assisted in the configuration of inputs and outputs
within the major components.
18.0.3 David SanchezDavid helped develop the Communications, Signals and Processing throughout the
system as well as the physically structure of the parking meter/sensor design. Courses on his
communication concentration such as Wireless Communications and Communication Systems,
helped him developed the communication and wireless communication of this project. His
knowledge in Signal Processing and previous work with companies involving Analog to Digital
Team #7 Electrical Engineering Design 2 Page 44
Converters and Digital to Analog converters was beneficial to the group in the development of
this project.
18.0.4 Jesus Luna Jesus joined the team after the concept stage in the first semester of the design. With a
concentration in Computers and experience with C++, Maya and C#, Jesus took the lead role in
the detailed microcontroller programming. Mr. Luna has taken several courses that exposed him
to the use of A/D and D/A converters while developing a sense for efficient and structured
coding in microcomputers. Jesus has also experience in the implementation of signal amplifiers
to integrate analog components into digital environments which became fundamental to the
project.
19.0 References1. "Restriction of Hazardous Substances Directive." Wikipedia, The Free Encyclopedia. 24 Nov
2009, 18:53 UTC. 25 Nov 2009. <http://en.wikipedia.org/w/index.php?title=Restriction_of
Hazardous_Substances_Directive&oldid=327710057>.
2. Cuartielles, David. "Arduino - Blink." Arduino - HomePage. 1 June 2005. Web. 03 Sept.
2009. <http://arduino.cc/en/Tutorial/Blink>.
3. Gray, Jeff. "Arduino - Begin." Arduino - HomePage. Web. 03 Sept. 2009.
<http://arduino.cc/en/Serial/Begin>.
4. Igoe, Tom. "Arduino - Button." Arduino - HomePage. 17 June 2009. Web. 10 Oct. 2009.
<http://arduino.cc/en/Tutorial/Button>.
5. "SparkFun Electronics - 7-Segment Serial Display." SparkFun Electronics - News. Web. 28
Oct. 2009. <http://www.sparkfun.com/commerce/product_info.php?products_id=9230>.
6. "Arduino Forum - Debounce Interrupt." Arduino - HomePage. Web. 20 Nov. 2009.
<http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1258424057/0#0>.
7. "Arduino - Reference." Arduino - HomePage. Web. 10 Nov. 2009.
<http://arduino.cc/en/Reference/HomePage>.
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8. "Arduino - ArduinoBoardMega." Arduino - HomePage. Web. 02 Sept. 2009.
<http://arduino.cc/en/Main/ArduinoBoardMega>.
9. Goddard, Phil. "Simulink Signal Viewing using Event Listeners and a MATLAB UI." Matlab
Central. 02 November 2009. Web. 02 November 2009.
<http://www.mathworks.com/matlabcentral/fileexchange/24294-simulink-signal-viewing-using-
event-listeners-and-a-matlab-ui>
10. "Using the Embedded MATLAB Function Block." The Mathworks. n.d. Web. 26 October.
2009. < http://www.mathworks.com/access/helpdesk/help/toolbox/simulink/ug/f6-6010.html>.
Team #7 Electrical Engineering Design 2 Page 46
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