Traffic Signs Outlined By

Traffic Signs Outlined by Solar-Powered LEDs

Senior Design May06-06

Final Report

Client

Senior Design

Faculty Advisors

Professor John Lamont Professor Ralph Patterson III

Team Members

Alex Beecher Jason Chose James Kopaska Matthew Treska

REPORT DISCLAIMER NOTICE DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer engineering course at Iowa State University, Ames, Iowa. This document does not constitute a professional engineering design. Although the information is intended to be accurate, the associated students, faculty, and Iowa State University make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

March 31, 2006 Table of Contents

1.1 List of Figures...... iii

1.2 List of Tables...... iv

1.3 List of Definitions...... v

SECTION 2 – INTRODUCTORY MATERIALS...... 1

2.1 Executive Summary...... 1

2.2 Acknowledgement...... 3

2.3 Problem Statement...... 3 2.3.1 General Problem Statement...... 3 2.3.2 General Solution Approach...... 4

2.4 Operating Environment...... 6

2.5 Intended Users and Uses...... 6 2.5.1 Intended Users...... 7 2.5.2 Intended Uses...... 7

2.6 Assumption and Limitations...... 7 2.6.1 Updated Assumptions List...... 8 2.6.2 Updated Limitations List...... 9

2.7 Expected End Product and Other Deliverables...... 10

SECTION 3 – PROJECT APPROACH AND RESULTS...... 12

3.1 Approach Used...... 12 3.1.1 End Product Functional Requirements...... 12 3.1.2 Resultant Design Constraints...... 13 3.1.3 Approaches Considered and One Used...... 14

3.2 Detailed Design...... 17 3.2.1 Charging Circuit Module...... 17 3.2.2 LED Module...... 19 3.2.3 Flasher-Dimmer Module...... 20 3.2.4 Flasher Module...... 22 3.2.5 Timer Module...... 23 3.2.6 Solar Cell Module...... 25 3.2.7 Battery Module...... 25

3.3 Specific Designs...... 28 3.3.1 Stop Sign Design...... 28 i 3.3.2 School Crosswalk Sign...... 32 3.3.3 Chevron Sign Design...... 34 3.3.4 Physical Design...... 38 3.3.5 Software Design...... 40

3.4 Implementation Process Description...... 46

3.5 End-Product Testing Description...... 47

3.6 Project End Results...... 47

SECTION 4 – RESOURCES AND SCHEDULES...... 48

4.1 Resource Requirement...... 48 4.1.1 Personnel Effort Requirements...... 48 4.1.2 Other Resource Requirements...... 50 4.1.3 Total Estimated Costs with Labor...... 52

4.2 Project Timeline...... 53 4.2.1 Project Schedule...... 53 4.2.2 Deliverables Schedule...... 53

SECTION 5 – CLOSURE MATERIAL...... 60

5.1 Project Team Information...... 60 5.1.1 Project Evaluation...... 60 5.1.2 Commercialization...... 63 5.1.3 Recommendation for additional work...... 64 5.1.4 Lessons Learned...... 64 5.1.5 Risk and Risk Management...... 65 5.1.6 Client Information...... 66 5.1.7 Faculty Advisor Information...... 66 5.1.8 Student Team Information...... 67

5.3 References...... 69

APPENDIX A...... 70

APPENDIX B...... 79

APPENDIX C...... 82

APPENDIX D...... 87

ii 1.1 List of Figures Figure 1: Picture of a sample location for the system equipment...... 6 Figure 2: PV Charge Controller...... 17 Figure 3: Jumper Placement For Night Light Mode...... 18 Figure 4: LED Cluster Configuration...... 20 Figure 5: Flasher-Dimmer Module...... 21 Figure 6: Flasher-Dimmer Wiring Diagram...... 22 Figure 7: Flasher Module...... 22 Figure 8: Timer Module...... 23 Figure 9: Solar Cell Used...... 25 Figure 10: Sample Battery Module...... 26 Figure 11: Battery Discharge Rate...... 27 Figure 12: Sample Battery Specifications...... 28 Figure 13: Stop Sign Block Diagram Circuit...... 29 Figure 14: Dimensions of Sign LED...... 31 Figure 15: Electro-optical Characteristics of LED cluster...... 32 Figure 16: School Crosswalk Block Diagram Circuit...... 33 Figure 17: Chevron Stop Sign Block Diagram Circuit...... 35 Figure 18: Dimensions of Sign LEDs...... 37 Figure 19: Electro-optical Characteristics of Chevron LED Bulb...... 38 Figure 20: SolidWorks Example of Parts to be Implemented...... 39 Figure 21: Block diagram for software...... 44 Figure 22: Software Screenshot Example Using Scottsbluff, NE...... 45

iii 1.2 List of Tables Table 1 - Original Personal Effort Requirements (In Hours)...... 48 Table 2 - Revised Personal Effort Requirements (In Hours)...... 49 Table 3 – Final Personal Effort Requirements (In Hours)...... 50 Table 4 – Original Time and Capital Cost for Major Resources...... 51 Table 5 – Revised Time and Capital Cost for Major Resources...... 51 Table 6 – Final Time and Capital Cost for Major Resources...... 51 Table 7 – Original Project Cost Estimates...... 52 Table 8 – Revised Project Cost Estimates...... 52 Table 9 – Final Project Cost Estimates...... 53 Table 10 – Project Schedule Through End of Project...... 54 Table 11 - Updated Project Schedule...... 55 Table 12 - Final Project Schedule...... 56 Table 13 – Deliverable Schedule Through End of Project...... 57 Table 14 – Revised Deliverables Schedule...... 58 Table 15 – Final Deliverables Schedule Through End of Project...... 59 Table 16 – Project Evaluation Ratings...... 63

iv 1.3 List of Definitions

DOT (Department of Transportation) - The United States Department of Transportation (DOT) is a cabinet department of the United States government concerned with transport. It was established by an act of Congress on October 15, 1966 and began operation on April 1, 1967. It is administered by the United States Secretary of Transportation.

Flasher/dimmer module – A module that will flash and dim the LED lighting load.

Lead-tin (Pb-Sn) – A specific type of battery.

LED (Light emitting diode) - A semiconductor device that emits incoherent monochromatic light when electrically biased in the forward direction.

National Electric Manufacturers Association (NEMA) – NEMA provides a forum for the standardization of electrical equipment.

Nickel cadmium (NiCad) – A specific type of battery.

Nickel metal hydroxide (NiMH) – A specific type of battery.

Photovoltaic charge controller (PV) - A module that will be used to interface the solar panel to the battery and load circuits.

v Section 2 – Introductory Materials The introductory materials contain the project executive summary, acknowledgements, problem statement, operating environment, intended users and uses, assumptions and limitations, and expected end product and other deliverables.

2.1 Executive Summary

This report describes in detail how the LED illuminated solar powered traffic sign project has been designed and implemented. The need for this project is to create a traffic sign that will stand out amongst all of the other distractions that drivers face. The manner in which attention shall be drawn to these signs is by illuminating them using LED’s. The initial design dealt with three varying types and intents for such traffic signs. The first was a stop sign (8 sided) that operates 24 hours per day, 7 days a week. The LED’s dim on cloudy days and during the night. The second is a school crossing sign (5 sided) that only operates during the hours of the day when children are present. Finally, the third is a chevron sign operating only at night. All signs flash at a consistent rate to meet the federal highway and safety regulations as well as bring positive attention to the signs. These LED’s are powered by a solar power system with battery backup for up to 7 days. This product is accompanied by a software tool for sizing the components of the design based on location and type of application. The expectation is that by drawing attention to these signs the number of accidents and traffic violations that occur in affected areas will be limited.

The design objectives that have been identified for this project are as follows. From this, the general design details were derived: 1. Fully functional stand alone system 2. Interactive software for user-definable system parameters

1 These make up the foundational requirements from which our project was based on. This project is made up of two components, hardware and software. The hardware consists of the sign assembly; solar panel, battery, LEDs, sign and pole. The LEDs are placed at the corners of the signs as to keep the integrity of the sign shape. The color of the LEDs is determined by the background color of the sign. The solar panel is in place to light the LEDs during the day when there is sufficient wattage being supplied and also to charge the battery which lights the LEDs during times when there is no sun light available.

The software consists of an Excel spreadsheet with 220 user selectable cities with user definable system parameters. The user definable parameters include number of LEDs on sign, total number of operational hours, the months the sign will be in use, and days of operation with no sunlight. These were made user definable so the client can see how their choices impact the cost of the unit (i.e. battery size and solar panel size are affected by operational parameters).

The final results of this project are defined through the testing of the software and the sign prototype. The testing of the software consisted of usability, reliability, and correct information output given the user’s inputs. The testing of the prototype consisted of dimming of the LEDs, charging the battery through solar power, and maintaining operation with a disconnected solar panel. The results of these tests were exceptional with all items performing as planned.

The recommendations for follow up work pertain solely to the software portion of the project. In the calculation formulas in the spreadsheet, the program assumes zero kilowatt-hours of solar radiation for the days with no sunlight available. This number is not actually zero. The follow up work should be to find out what this number actually is on cloudy days as well as during the night. The reason for this follow up is because this lack of number in kilowatt-hours on days without sunlight drastically changes the size of battery and solar panel needed and thus negatively impacts the overall cost of the unit desired.

2 2.2 Acknowledgement The design team would like to thank the faculty advisors; John Lamont and Ralph Patterson. They would also like to thank Professor Vik Dalal and Kurtis Younkin of the Iowa DOT. These gentlemen have greatly assisted the team by donating their time and technical advice. Their support is deeply appreciated. Thanks also goes out to Al Kopaska of Al’s Electric, Dan Krogman of Kurrent Electric, and Brad Brunia of Electrical Wholesale for generous donations of parts and supplies.

2.3 Problem Statement The two following sections contain a more detailed description of the executive summary from Section 2.1. The problem will be presented in more detail and the solution approach will be given.

2.3.1 General Problem Statement There are varying times and applications where this design project can be effective. One such application would be in areas where traffic is flowing at a fast pace and a stop sign has been placed in an inopportune area. It is difficult to see such stop signs when traveling at a high rate of speed. Also, areas where there has been a lot of overgrowth due to the presence of trees and other natural obstructions can be a problem. Another application is where there are school crossing areas on busy intersections that need to be brought to the attention of drivers. A final application can be implemented when there is a sharp curve in the road that is hard to see at night. Drawing extra attention to the chevron sign can be very beneficial in such a situation.

These are some examples of areas where drivers are unsuspecting of a change in traffic situations and environments. The intention is to eliminate this possibility. Distractions are plentiful in the driving world and it is desired for this project to create a positive “distraction”; one that refocuses the driver on the task at hand.

3 This project also needs to be accompanied with an easy to use software program that directs the user to the proper equipment for their desired operation.

2.3.2 General Solution Approach The potential solution to this problem is the implementation of LED-delineated traffic signs. This presence of the LEDs will draw attention to the signs that may otherwise go unnoticed. The traffic signs considered are the stop sign, school crossing sign, and chevron sign. Each sign will be accompanied with the same number of LED’s as it does corners. For example, the stop sign will have eight LEDs for its eight corners, while the school crossing sign with have only five LEDs for its five corners. The color of the LEDs is determined by the background color of the sign itself. Again, the stop sign will have red LEDs accompanying its red background with the school crossing and chevron signs having yellow LEDs. The school crossing sign and the stop sign will also use varying rates of intensity throughout the 24-hour day. This rate will be ever changing and never exceed the preset minimum dimming level determined by the dimming circuit with which each sign will be accompanied. The dimming circuit uses a photocell to measure the available ambient light. This will then adjust the LED output regarding the amount of light measured. The user-definable preset minimum will guarantee the LED output will never drop lower than desired. The chevron curve sign will use LEDs that are less bright than the other two applications, due to the fact that this sign will only be illuminated in hours of darkness. The school crossing sign and the stop sign will also be equipped with a flasher/dimmer circuit that will flash the LEDs at a Federal Highway Administration acceptable rate of no less than 50 times per minute and no greater than 60 times per minute. The chevron curve sign will employ only a flasher and not a dimmer. Solar panels will be used by all the signs to power the LEDs and other load circuitry as well as charging the backup battery for each unit. Each unit shall also have a charge controller set up to protect the unit from over voltage, over current, and power bleed back to the solar panel.

4 The school crossing sign will possess a timer circuit allowing the sign to operate only during hours school children will be crossing the street. It will also have a kill switch and an override switch allowing the user to disable the system during periods when school is not in session and run the sign during times children will be present not during normal school hours. For example, during the weekend and summer break the kill switch will be used, however, during an after school sports event the override switch can be used. This unit shall also implement a flasher/dimmer circuit, battery backup, PV charge controller module, solar panel, and LEDs. An in depth description of these components shall appear in the design section.

The stop sign will be equipped with a flasher/dimmer module and a PV charge controller module, along with the solar panel, battery and LEDs. An in-depth description of these components shall appear in the design section.

The chevron sign will be implemented with fewer components that the other signs due to its particular application. It will not need a timer or a dimmer due to its night time operation. It will still employ the PV charge control module, batteries, LEDs, solar panel, and a special flasher circuit. The PV charge controller will operate in night mode so that additional photo cell control will not be necessary. An in-depth description of these components shall appear in the design section.

Signs can be designed suing the software also being developed by the project team. This will allow the designer to personalize the particular sign to his or her intended uses. This software will be in the form of a Microsoft Excel Spreadsheet. It will take as input the closest big city to the user’s location in the continental United States given from a list, and the type of sign desired. The software will output the size of battery needed, the size of solar panel needed, and the optimal angle for which the solar panel is to be mounted for that area of the nation based on calculations devised by the group.

5 2.4 Operating Environment The final design for the three systems must operate in all weather conditions in the continental United States. For the most part, they will be immobile. Once the signs are on site and assembled, they should not need to be moved again. These signs can be placed at any roadside, intersection, or on an overhead billboard. The operating/control power system must be located high enough off the ground so that in areas that receive large amounts of snowfall it will remain unaffected. All electronics and the control panel will be enclosed in a weather proof casing for protection from adverse weather conditions.

Figure 1: Picture of a sample location for the system equipment (courtesy of Jim Kopaska)

2.5 Intended Users and Uses The following two sections include information about the intended uses and users for the LED-delineated traffic signs.

6 2.5.1 Intended Users The three systems will be designed for initial use by the Department of Transportation or a municipality. The setup will be such that is it easily maintainable. The only work that should need to be performed on the unit itself after installation is the replacement of the rechargeable battery pack and any LEDs that may fail. Initial installation will require little technical background. The only crucial element will be assuring that the solar cell in pointed and locked in at an appropriate angle and direction. A north/south indicator arrow will be on the unit for ease of installation. Future considerations may be given to implementing such a design for individual uses by other entities. These may include construction firms, city organizations, and school districts. Application of these designs will be required to adhere to any federal regulations that may apply.

After installation, the systems will be used by any motorists or traversing the roads where these signs have been placed. It is intended to be a beneficial tool instead of an added distraction.

2.5.2 Intended Uses These systems shall be used as a supplemental warning system for approaching drivers. Currently road signs are typically reflective so as to draw attention to them. This device will take that one step further and create a highly visible warning to notify drivers of the situation. The uses specific to the design shall be at locations on the road where there are stop signs, school crosswalks, and chevron signs.

2.6 Assumption and Limitations The two following sections are lists of the assumptions and limitations applicable to the project.

7 2.6.1 Updated Assumptions List Below is an updated list of the assumptions pertaining to the group project. Updates include better definition of assumptions as well as added assumptions regarding the software module.  The signs shall be powered to accommodate abnormal weather patterns.  The systems will operate at full illumination during required hours.  The signs will operate at full illumination during times of high sunlight.  The stop sign and school crossing sign will dim proportional to the amount of ambient light measured by the dimming circuit.  The school crossing sign will operate only during user definable hours.  Installation shall be governed by appropriate DOT/municipal officials.  Each corner of each sign will contain an LED so as to not confuse motorists as to the type of sign they are approaching.  The LED’s will match the background color of the sign to which they are attached.  The system shall be able to be entirely supported by the sign itself and the device that it is mounted upon.  All wiring and components shall be designed to withstand worst case weather scenarios such as rain, snow, sleet, and extreme temperature levels.  Worst case scenarios are determined through research via the National Weather Service.  The systems housing will be easily opened to allow change of battery.  The unit shall have anti-vandalism features such as a locking case for the control systems and protection for the exposed wiring.  The housing for all units will be mounted on the bottom of the sign pole.  The units shall be operational in the continental 48 states.  Final product must adhere to all applicable state and federal regulations.  The intended user has access to Microsoft Office knows how to use Excel.

8  The installer will never adjust the mounting angle of the solar panel after initial installation. Therefore, sunlight data shall be taken on annual minimum averages  One hour of solar insulation will be taken as a default value for days of no sunlight

2.6.2 Updated Limitations List Below is an updated list of the limitations pertaining to the group project. Updates include better definition of limitations as well as added limitations regarding the software module.

 Changes in weather patterns not represented by historical data cannot be taken into account.  The electrical components need to be housed in a NEMA standardized enclosure.  The LEDs on the signs with flash no more that 60 times per minutes and no less that 50 times per minute.  The LED color choice shall not mislead motorists as to an emergency situation.  Use above and beyond intended hours may cause the unit to malfunction due to lack of necessary power to operate.  The unit cannot be completely protected from vandalism.  The batteries shall need to be changed as necessary. Projected change period is once every seven to eight years depending on type of implementation. The lifecycle is determined from data given by the battery manufacturer.  Sunlight data used in the software can only be given as a city closest to the installation location.

9 2.7 Expected End Product and Other Deliverables The end product of this project will depend on the number of signs requested for implementation. Design and reference material should not vary.

Design - A full design report A complete design report shall be submitted to the appropriate individuals for review. This report shall contain a list of components, assumed operating conditions, operating voltages, and costs that will be incurred. A schematic will accompany this report which will lay out exactly how the system shall be powered. Data shall be given regarding the current draw of the LED’s and the illumination levels that they will provide at full intensity. Software will also be included and given in the form of a Microsoft Excel spreadsheet allowing the user to input his location, or biggest city located nearest to him given from a list included, in the continental United States and the type of sign desired. The resulting output will state what size battery is needed, what size solar panel is needed, and the optimal angle for which the solar panel is to be mounted according to the user’s location. It will also output electrical consumption for project comparison purposes.

Prototype - A fully working, scaled testable system One working sign has been developed, tested, and ready for demonstration. The application is a stop sign that will operate 24 hours per day in Ames, Iowa. The stop sign will operate with LEDs flashed no less that 50 times per minute and no more than 60 times per minute. It will run at full illumination during daylight and will continually dim the LEDs proportional to the amount of measured ambient light and never exceed a minimum preset dimming level during hours of darkness. The continually dimming feature and the minimum dimming level will be determined by the dimming circuit that has been implemented in the prototype. The prototype is accompanied by a working software program in Microsoft Excel. This program will allow the users to input such information as their location, or biggest city closest to them given from a list included, in the

10 continental United States and the type of sign preferred. The output will state what size battery is needed, what size solar panel is needed, and the optimal angle and direction for which the solar panel is to be mounted according to the user’s location. The final prototype implements the worst case scenario, i.e. operation 24 hours per day for 7 days a week.

11 Section 3 – Project Approach and Results In order to be successful with this project, technical, security, intellectual, and safety considerations will first need to be determined. The functional requirements of the end-product will also be outlined in this section. Early identification of risks and how they will be handled will also ensure a successful project.

3.1 Approach Used The following sections of this report cover the technical constraints and approaches that have been considered and chosen for the design of the Solar Powered LED illuminated traffic sign. Testing considerations and recommendations for the project continuation are also included.

3.1.1 End Product Functional Requirements The following list includes the functional requirements specifications:  Reliability in absence of sun light The unit shall remain functional in the absence of sunlight for up to 7 days.  Reduced illumination during hours of darkness The LED’s shall dim during hours of darkness to reduce illumination. This is to prevent a blinding distraction to the driver during the night instead of a positive attraction of attention.  LED flashing LED’s shall flash on and off at a rate of at least 50 times per minute, but no more than 60 times per minute.  Solar charging protection A charging circuit shall prevent over-voltage and over-current supply to the battery and load from the solar cell.  Special applications Photocell and time clock applications shall be used as necessary per end- user requirements.

12  Software inputs Software shall allow user to input desired application and physical location to determine components that shall be used. User will also input hours of daytime and nighttime operation as well as a reliability factor for number of days of operation without sunlight.  Software applications Software shall select best case installation angle given fewest hours of solar radiation for a given location. It will also read in user inputs and apply them to the calculations section of the software.  Software outputs Software output shall include battery, solar cell, and installation angle and direction that will be necessary for the selected application. It will also output electrical consumption for project comparison.

3.1.2 Resultant Design Constraints The constraints list describes the restrictions on the end product design:  Budget constraints Money allocated for this project is $250.  Dimensions Electronic enclosure was installed close to ground to prevent serious injury in case of an accident with the pole.  Economic Must find balance between efficiency and affordability.  Environmental Battery selection is based upon the most environmentally friendly option within the budget constraints.  Weather This unit withstands most reasonable weather extremes (i.e. temperature, moisture) found within the continental United States.

13  Vandalism The components were selected and assembled in such a manner that vandalism is deterred. The control system is housed in a locked container to thwart tampering.

3.1.3 Approaches Considered and One Used The technology considerations list describes the available technologies which were considered for the implementation of the final design.

 LED’s: Using a 12-Volt operating system the group considered a 55,500 milli-Candela and a 102,400 milli-Candela LED cluster. These units have an 1156 base. The 55,500 milli-Candela LED cluster was selected to ensure visibility at required approach distance of 925 feet as specified by DOT regulations.

Advantages The following is a list of advantages for using the 55,500 mCd bulb: . Incredibly high level of illumination for all applications . Base type is very common. . 12-Volt requirement is very compatible with solar cell outputs. . Sufficient information is available to aid in design. . The necessary parts for implementation are easier to locate. . Low energy usage in comparison to incandescent bulb.

Disadvantages The following is a list of disadvantages for using the 55,500 mCd bulb: . Draw high current levels. . Require large battery back-up energy supply. . Physical size is larger than desired. . More expensive than similar bulbs with less illumination.

14  Batteries: Types considered included Pb-Sn acid, NiMH, and NiCad. NiMH was selected based upon environmental operational range, affordability, memory affect, and environmental friendliness.

The following is a list of advantages for using the nickel metal hydroxide (NiMH) battery: . Battery has no memory affect during charging and re-charging process. . Has largest operational temperature range for money spent. . Does not release harmful chemicals to the surrounding environment. . Most affordable given system requirements. . Physical weight is less than that of a Pb-Sn battery.

Disadvantages The following is a list of disadvantages for using the nickel metal hydroxide (NiMH) battery: . Pb-Sn would operate at lower temperatures . Costs more than NiCad batteries. . This battery is difficult to locate. Only located distributor was in Australia.

 Solar Cell: A 14.2 voltage base was the obvious selection based on operating constraints of other components.

Advantages The following is a list of advantages for using a solar panel with a 14.2 voltage base: . Easily compatible with 12-Volt battery system. . Widely available for implementation. . The overall design would be less complicated. . Most common application in use throughout the market.

15 Disadvantages The following is a list of disadvantages for using a solar panel with a 14.2 voltage base: . Physical size may be quite large to generate enough power supply. . Mounting considerations are difficult to judge. Physical size may require heavier duty mounting hardware for large cells in comparison to smaller cells. . Monetary cost may be quite large.

 Software: Comparison was made between web-based, C/C++ programming languages, Excel spreadsheet, and simple reference manual (not interactive). The excel spreadsheet was selected to create a user friendly reference while still allowing customer interaction.

Advantages The following is a list of advantages for using an Excel spreadsheet for the software: . Team is competent in Excel programming. . Allows user to specify desired applications. . Easy decision making process for end-user. . The overall design would be less complicated. . The cost of the design would be lessened.

Disadvantages The following is a list of disadvantages for using an Excel spreadsheet for the software: . Error checking may be easier in a different programming language. . Does not eliminate human error. . Exact locations throughout the continental U.S. cannot all be taken into account. . Not as accurate as calling manufacturer for exact reference.

16 3.2 Detailed Design The following sections lay out the specific components utilized in the designs. These components will be defined in great detail at first and then referenced by specific applications.

3.2.1 Charging Circuit Module Figure 2 below gives a model of the charging circuit selected for all designs. This circuit will serve as over current and over voltage protection for the load and battery circuit.

Figure 2: PV Charge Controller (courtesy of powerstream.com)

The unit pictured has external terminals for solar panel input, battery charging output, and load outputs. LED indicators are also located on the unit to show the status of current charging operations. A table is also located on the unit to help the user understand what each LED configuration means.

17 Features of unit:  Electronic blocking to protect against reverse polarity, connection of PV panel, and block current from battery to PV panel when voltage of battery is higher than PV panel.  Suitable for PV panels with open circuit voltage from 17-23 Volts.  Rated charging/load current 12 amps and peak charging/load current 20 amps.  Built in microprocessor for PV charge control to maximize the charging efficiency.  Overcharge and over discharge protection.  Over temperature protection to monitor transistor temperature within unit.  Battery short circuit protection.  Battery reverse polarity protection.

This unit comes with a night light mode operation and that can be enabled by placing a jumper as shown below.

Figure 3: Jumper Placement For Night Light Mode (courtesy of powerstream.com)

To activate night light mode a jumper must be placed across J3(5/6).

18 Below is a list of product specifications. For further information regarding this unit refer to Appendix A located at the end of this document.

Specifications

3.2.2 LED Module The LED’s used in the designs below will vary in color and axial intensity. Each design will color match the LED to the background color of the sign itself. The LED’s selected have a BA15 base common to most automotive applications. The LED’s operate on the same 12-Volt base although current regulation may have them emitting light at a lower axial intensity. The LED’s will be in a cluster configuration to emit optimal intensity. Figure 4 provides a picture of an LED lamp with a cluster configuration.

19 Figure 4: LED Cluster Configuration (courtesy of theledlight.com)

Detailed product specifications for the LED’s will be provided in the applicable design sections below.

3.2.3 Flasher-Dimmer Module Figure 5 gives a picture of a combination beacon flasher with automatic dimming. This unit will be implemented in both the stop sign and school crossing designs. Its purpose is to meet the federal regulations regarding flashing rates as well as providing dimming capabilities given ambient lighting. It will be continuously dimming the LED’s to compensate for changes in ambient light levels.

20 Figure 5: Flasher-Dimmer Module (courtesy of theledlight.com)

This unit will flash the LED’s mounted on the applicable sign at a rate between 50 and 60 times per minute to match DOT regulations. The accuracy of this unit allows for stability of +/- 1 flash per minute. Dimming shall be done to coordinate with the ambient light of the area. As surrounding light dims, so will the LED’s. A maximum dimming percentage can be set by the user. Suggested dimming should not drop below half of original intensity. Automatic dimming allows battery pack and solar array sizing to be reduced, thus reducing costs. A photoresistor is included with this component to monitor surrounding ambient light conditions. A diagram of physical implementation of this unit is shown in Figure 6.

21 Figure 6: Flasher-Dimmer Wiring Diagram

Detailed product specifications can be referenced at the end of this document in Appendix B.

3.2.4 Flasher Module The chevron sign will not require dimming capabilities since it will only be operable during hours of darkness. Given this characteristic it is unnecessary to implement the flasher dimmer described above. For this application a simple flasher module shall be used to keep costs down. Figure 7 gives a picture of the flasher module that shall be implemented in that design.

Figure 7: Flasher Module (courtesy of amperite.com)

This flashing unit shall also comply with federal regulations regarding flashing rates. It shall flash at a rate of 60 flashes per minute with a 50% duty cycle.

22 Detailed product specifications can be referenced at the end of this document in Appendix C.

3.2.5 Timer Module The school crosswalk implementation will require time clock control to monitor operating times. It shall be set to operate only during the hours that students shall be present. In order to achieve this functional requirement a timer module shall be placed in the circuit that can be programmed appropriately. Figure 8 gives a picture of the timer module that shall be implemented for this application.

Figure 8: Timer Module (courtesy of artisancontrols.com)

23 Features  56 programmable events per week  12V-DC operation  5-ampere maximum output  Transient protected

Specifications

Operating Voltage 12V DC, 24, 115, 230V AC 50/60 Hz. Output Relays Two (2) SPDT Relays Contact Rating Contacts UL rated for 5-ampere resistive service at 120V AC, 1/8 HP. Display 4-digit 7-segment LED 0.5 inch high characters. Clock Type 24 hour (00:00 - 23:59) Does not require batteries or power to sustain timing during timing failure. Battery Backup power required only to operate relays and display. Clock Accuracy +/- 2 minutes per month at 25 deg. C. Programmable Eight (8). Events Per Day Programmable Fifty-Six (56) Events Per Week Protected by silicon transient suppressors which respond to transients with 1 x 10-12 seconds to a peak pulse power dissipation of 1500 watts, with Transient Protection transient surge currents to 200 amperes for duration of up to 1/120 second at 25 deg. C. 1500V RMS. between all terminals to PC board and between all relay Dielectric Strength contacts and input voltage. Keypad 0 - 9, #, * tactile type. Enter time of day - Enter day of week - Enter event timing data - Scroll daily Keypad Commands programmed events - Clear all memory. Open PC board, material CEM-1 (PC-75) 94V-0 UL File #E67203(M) Construction category ZPMV2.

More product specifications can be found at the end of this document in Appendix D.

3.2.6 Solar Cell Module

24 The solar cells for these designs will all operate on a 14.2-volt platform. This voltage was selected to allow adequate charging for a 12-volt battery. The physical size of the solar cell used will vary based on the location and application that it is serving. Sizing will be determined by the software reference that will accompany the product. A 5 watt, 12 V, 350mA panel was acquired and is being implemented in the prototype Figure 9 is a picture of the solar cell that is being utilized in the implementation of the design.

Figure 9: Solar Cell Used

3.2.7 Battery Module The battery type selected for the design is a nickel metal hydride (NiMH). The size of the battery shall be determined through the use of the software reference that shall accompany the product. The battery will operate on a 12-volt base. The battery will also be fully rechargeable. Figure 10 gives a picture of a sample battery that may be implemented in the team’s designs.

25 Figure 10: Sample Battery Module (courtesy of windsun.com)

This battery is expected to operate in all applicable weather conditions throughout the continental U.S. It is also favorable for the battery selected to have a flat discharge rate that did not ramp down with usage. The reasoning behind this is to keep the unit fully operational until the battery is nearly dead. Any other type of discharge rate can adversely affect the way in which other components operate. Figure 11 below gives a sample discharge rate diagram that displays the desired application.

26 Figure 11: Battery Discharge Rate (courtesy of batterywholesale.com)

The system load will operate at less than 1.5A for any of the designs. This leaves the two curves furthest to the right as possibilities. Both of these curves are representative of the desired effect.

Figure 12 gives a list of specifications for a sample battery that may be selected for implementation.

27 Figure 12: Sample Battery Specifications (courtesy of batterywholesale.com)

Final battery selection for a given application will be based upon outputs determined by software as well as temperature range requirements per physical location. The battery being utilized in the prototype is a 7 amp hour 12 volt battery obtained from one of the group members.

3.3 Specific Designs The following sections lay out the specific designs for each application. These designs implement the modules defined above. This section also incorporates a physical design as to assembly and installation characteristics.

3.3.1 Stop Sign Design For the stop sign application, the requirements for operation are as follows:  24 hours a day, 7 days per week operation  50 flashes per minute < flash rate < 60 flashes per minute  8 LED Load at 1120 mA

28  Automatically reduces or increases flash intensity to correspond with ambient brightness.  Battery and solar collector size to be determined by geographical area and load factor.

Based on the design criteria, the flash/dim module will be employed in this application. A block diagram of the system is shown in Figure 13 for clarity.

Figure 13: Stop Sign Block Diagram Circuit

29 The system will initially start with a fully charged battery. After placing the system into operation, the solar collector will collect solar energy to sustain the system’s power demand. The flasher/auto dim unit will pulse the LED’s at 60 flashes per minute with a 50% duty cycle. This same module will also limit the brightness as ambient light conditions change, which makes the system much more efficient than operating at full intensity when ambient light levels are high. The battery and solar collector size will be chosen based on load requirements and on what part of the continental United States the sign will be used. The current demand is as follows:

8 LED load 1120 mA Drive Circuitry to operate flasher/auto dim 3.17 mA Charge controller operating current 30 mA Total current demand 1153.17 Ma

For this application, the LED’s need to be visible at 950 feet as dictated by DOT regulations. This distance is required for all hours of the day in all sunlight conditions. A LED that has a rated axial intensity of 102,400 mCd was chosen to ensure that the LED would be visible from 925 feet during times of high ambient sunlight. The specifications of the LED selected are shown in Figures 14 and 15 below.

30 Figure 14: Dimensions of Sign LED (courtesy of theledlight.com)

31 Figure 15: Electro-optical Characteristics of LED cluster (courtesy of theledlight.com)

3.3.2 School Crosswalk Sign For the school crosswalk application, the requirements for operation are as follows:  6 hours per day, 5 days a week as programmed by user.  50 flashes per minute < flash rate < 60 flashes per minute.  5 LED load at 700 mA.  Automatically reduces or increases flash intensity to correspond with ambient brightness.  Battery and solar collector size to be determined by geographical area.

32  Overrides in place to allow operation outside the programmed run times.

Based on the design criteria, the flash/dim module will be employed in this application. A block diagram of the system is shown in Figure 16 for clarity.

Figure 16: School Crosswalk Block Diagram Circuit

33 The system will initially start with a fully-charged battery. After placing the system into operation, the solar collector will collect solar energy to sustain the system’s power demand. The flasher/auto dim unit will pulse the LED’s at 60 flashes per minute with a 50% duty cycle. This same module will continuously control LED brightness corresponding to ambient light levels. This makes the system much more efficient than operating at full intensity when ambient light levels are high. The battery and solar collector size will be chosen based on load requirements and what part of the continental United States the sign will be used. The current demand is as follows:

5 LED load 700 mA Drive Circuitry to operate flasher/auto dim 3.17 mA Charge controller operating current 30 mA Timer module operating current 350 mA Total current demand 1083.17 mA

For this application, the LED’s must be visible at 925 feet as dictated by DOT regulations. This distance is required for all hours of the day in all sunlight conditions. A LED that has a rated axial intensity of 102,400 mCd was chosen to ensure that the LED would be visible from 925 feet during times of high ambient sunlight. Figures 14 and15 above give the specifications for the selected LED.

3.3.3 Chevron Sign Design For the chevron sign application, the requirements for operation are as follows:  Hours of low or no light, 7 days per week operation.  50 flashes per minute < flash rate < 60 flashes per minute.  4 LED load at 360mA.  Battery and solar collector size to be determined by load and geographical area.

34 Based on the design criteria, the flasher module will be employed in this application. A block diagram of the system is shown in Figure 17 below for clarity.

Figure 17: Chevron Stop Sign Block Diagram Circuit

The system will initially start with a fully-charged battery. After placing the system into operation, the solar collector will collect solar energy to charge the battery as needed. Since this sign’s load is much smaller than the other signs,

35 the battery used in this sign will last longer per charge than the other signs. The battery will still be determined by the customer’s load and location, however, since some areas (like Washington) experience periods of darkness greater than those of more tropical areas (like Florida). The flasher unit will pulse the LED’s at 60 flashes per minute with a 50% duty cycle. The current demand is as follows:

4 LED load 360 mA Drive Circuitry to operate flasher/auto dim 3.17 mA Charge controller operation current 30 mA Total current demand 393.17 mA

For this application, the LED’s need to be visible at 950 feet as dictated by DOT regulations. This distance is required for all hours of the day in all sunlight conditions, but this sign will only operate during low or no sunlight periods. A LED that has a rated axial intensity of 55,500 mCd was chosen to ensure that the LED would be visible from 925 feet during times of little or no sunlight. The specifications of the LED selected are shown in Figures 18 and 19:

36 Figure 18: Dimensions of Sign LEDs (courtesy of theledlight.com)

37 Figure 19: Electro-optical Characteristics of Chevron LED Bulb (courtesy of theledlight.com)

3.3.4 Physical Design Figure 20 is a SolidWorks design of what a physical model would look like. This section will outline the specific characteristics of parts that will be needed to physically implement this design.

38 Figure 20: SolidWorks Example of Parts to be Implemented

The following is a list of necessary components for physical implementation of the product:  Telespar tubular post  36” DOT regulation stop sign  8 BA15 LED sockets  12 AWG wire to feed from solar collector to PV charge controller

39  18 AWG wire to interconnect all other electrical components  NEMA 3R enclosure for electronic component housing  ½” PVC conduit for wire raceway  ½” PVC conduit straps for mounting to Telespar post  ½” PVC TB connector for junction to back of sign  NEMA 3R junction box for termination on back of sign  8 raceways out to LED sockets  Silicone calking for additional sealant from the elements  Sockets attached to back of stop sign using pop rivets  Various mounting hardware for attaching solar cell unit to conduit as well as NEMA enclosures to the Telespar post

3.3.5 Software Design The software accompanying this product is an Excel spreadsheet application. This spreadsheet allows the user to input crucial data for the specific application and perform a series of calculations based on this data and other collected from the National Renewable Energy Laboratory (NREL). Below is a list and description of the inputs that the user will provide. Calculations and block diagrams will be provided later in this section to better lay out how this data will be used.

 Location- User can select one of 239 continental U.S. cities. Selection of this location will provide the calculations with worst case solar radiation levels for the selected area of the country.  Programmable/Not programmable- This will add programming capability to the sign  Times of day of operation- This section will allow the user to select when the sign will operate, and automatically choose the appropriate LED  Hours of night usage- This input will be directly used in the calculation section to determine power consumption during hours of darkness.

40  Hours of daytime usage- This input will be directly used in the calculation section to determine power consumption during hours of daylight.  Number of LED’s- User enters the number of LED’s  Days of operation without sunlight- This input will give a stability factor for the product. The lower this number is, the more affordable the product will be. The higher the number, the less affordable it will be. This option allows the user to compare reliability versus cost. This input will be used in the calculations for determination of battery sizing to ensure appropriate power storage capabilities.

Error checking will be performed on these data entries to ensure that the total number of hours is not greater than 24 and that the number of LED’s selected is feasible for application. A reasonable limit for this number will be 10, but it may be less than 10. The user input for days of operation without sunlight will be limited to a maximum of 7.

This program will output for the user a battery size, solar cell size, and appropriate solar panel angle of installation. Appropriate solar panel angle of installation will be determined from the database of information obtained from NREL. Battery and solar cell size will be determined using the calculations predefined in the program. The following is a sample set of calculations for a given application:

User inputs:  Birmingham, AL  24/7, 8 LED stop sign  12 hours of night usage  12 hours of daytime usage  5 days of operation without sunlight

41 Calculations: Total current draw 1200 mA (from earlier section on stop sign design) Power consumption daytime (100% operating current): 1200mA*12 V= 14.4 Watts Power consumption nighttime (75% operating current): 900mA*12 V= 10.8 Watts Full day power consumption 14.4 W*12 hours + 10.8 W*12 hours= 302.4 W*hours per day 5 day operation without sunlight 302.4 W hours per day * 5 days = 1.512 kW hours Amp hour requirement 1512W hours / 12 V = 126 Amp hours

This power requirement could be met using a Sun Xtender PVX-1080T battery that is rated for 126 Amp hours over a 120 hour time period.

Selection of Birmingham, AL gives a solar radiation level of 2.8 at an installation angle of +15 degrees latitude. This information leads to the following calculations.

1 kW hour/ m^2/day = 15 watts/in^2/hour using simple conversions

This application gives 2.8 * 15 watts/in^2/hour = 42 W/in^2/hour

The solar cells selected for this design will operate at a 12% efficiency rate as predefined by the programmer. This gives a real power production of 5.04 W/in^2/hour.

42 It is desirable for the battery to be recharged in a single days’ cycle. This means that in 2.8 hours, 1512 W hours will be produced. In order to achieve this goal a solar cell would be sized as follows:

5.04 W/in^2/hour * 2.8 hours = 14.112 W/in^2

1512 W / 14.112 W/in^2 = 107.143 in^2

This would require a solar cell that would be roughly 10” x 11”.

Given these calculations the software would output to the user the need for a 126 Amp hour battery with a 10” x 11” solar cell mounted at an angle of +15 degrees latitude. This software will also output to the user the electrical consumption of the selected unit. This number will not affect the decision making process for the user, but simply serves as a reference for project comparisons.

Per discussion with Dr. Dalal the project team has assumed a solar isolation value of 1 hour for days of complete overcast conditions. This assumption affects the calculations above and is represented in the software package delivered with the prototype. The team contacted NREL for an exact value for the Ames, IA area, but was unable to attain this desired information.

Figure 21 gives a step by step block diagram of the process served by the software.

43 Type of Hours of Hours of sign use use daytime nighttime Days of Location operation without sunlight Input processing and error checking

Data Calculations base

Outputs

Battery Solar Electrical Mounting panel consumption position

Figure 21: Block diagram for software

All of the data from NREL is in the Excel spreadsheet program. User is able to select the nearest city by clicking on a drop down menu on the spreadsheet. The software then finds the number of isolation hours outputted from the location’s page. Figure 22 gives a screenshot of this initial page.

44 Figure 22: Software Screenshot Example Using Scottsbluff, NE

45 After this number has been found, the calculations are performed and the outputs are generated for the user. These outputs will guide the user in selection of appropriate components. This software also allows the user to look at the implications of using different types, sizes, and levels of reliability when selecting a final product.

3.4 Implementation Process Description The implementation process used all of the components mentioned in the detailed design section. The sign itself was mounted to an 8 foot piece of unistrut using 2 half inch bolts. A component box was made out of compressed wood for the sake of ease and least expense. This box was mounted towards the bottom of the unistrut pole and attached in a similar method as the sign. Half inch conduit was used as a raceway for the necessary wiring and was secured to the pole using hose clamps. Slotted flexible tubing was used as the raceway for taking the wiring to the individual sockets mounted to the sign. The sockets were mounted to the sign using eighth inch pop rivets. The solar panel was mounted on a piece of half inch compressed wood and then subsequently the wood was attached to a used satellite dish mounting system. The satellite mounting bracket was then mounted to the post using two 2 inch U-bolts. The sign is supported at the bottom using band clamps and screws to secure it to an old beer keg filled with sand. The sign shall be mobile for the sake of demonstrations by using a two wheeled hand cart.

The software implementation process consisted of building an extensive spreadsheet, with one worksheet for all locations specified on NREL’s website. Then, using cell commands and drop down menus, the program selects and sorts this data and imports it to one main calculation page. The software also uses drop down lists to accept user inputs. This ensures that realistic data is being inputted to the software calculations. Outputs are displayed below the input section, which consist of best mounting angle, battery size, and solar panel size.

46 The implementation thankfully went as planned. No major obstacles were faced or had to be dealt with. Some issues with the calculations arose during the software setup but were quickly solved by communicating with experts in the field.

3.5 End-Product Testing Description Testing was performed on both the software and the stop sign prototype. Software testing was conducted by both members of the team as well as classmates who were unfamiliar with the project. Primarily this testing consisted of error checking. The users were instructed to input any values that they desired to create their own sign. Group members then verified that these numbers went through the correct calculations and outputted accurate information to the user. Testing was very successful and was met with many compliments from those utilizing this software tool.

Testing on the sign prototype was a little more complicated. A series of tests were conducted to monitor actual performance of the components utilized. Such testing included the dimming function due to ambient light conditions and the low voltage cut off feature to ensure that the battery was never completely drained causing permanent damage. Visual inspection was also done to ensure that the light was visible at a minimum of 925 feet as regulated by the DOT. The prototype worked as expected and met all necessary regulations and specifications. Accurate testing for all situations was not possible due to current weather conditions in Ames, IA, but it is believed that the results could easily be replicated in the location of choice if such a testing process would be required.

3.6 Project End Results The project was a resounding success. Implementation and testing went very smoothly and validated the work and research that the group had been doing over the course of the last several months. The greatest downfall of the entire project was the lack of ability to do diverse testing in various locations. Such

47 testing and use of varied sizes of components would have further solidified the effectiveness and practicality of the design.

Section 4 – Resources and Schedules

4.1Resource Requirement This section will delineate personnel requirements for this project. These include personnel/labor requirements, part requirements, and total cost.

4.1.1 Personnel Effort Requirements Table 1 displays the estimated amount of time each team member will contribute towards major steps in producing the end product. Since this is an estimation of labor time, hours may vary depending upon possible design changes or unforeseeable variables that may occur throughout the project’s design.

Table 1 - Original Personal Effort Requirements (In Hours) Alexander Jason James Matthew Task Name Beecher Chose Kopaska Treska Total Hours Select Signs 1 1 1 1 4 Select LEDs 12 14 15 13 54 Determine Electrical 40 42 43 42 167 Parameters Select Solar Panel, Battery, 35 37 39 37 148 and other Hardware Design Circuit 31 33 34 33 131 Plan Construction 21 22 23 22 88 Construct Prototype 32 34 35 34 135 Test and Refine Prototype 43 48 46 47 184 Finalize Prototype 10 14 13 15 52 Documentation 35 18 19 17 89 Poster 12 11 11 12 46 Software Development 65 71 74 69 279 Total Hours 337 345 353 342 1377

48 Table 2 displays the revised amount of time each team member has and will continue to contribute towards major steps in producing the end product. Since some of steps have not yet occurred at this time, the estimation of labor time is still used in sections. This can result in a variation of hours as will be seen in the completed project.

Table 2 - Revised Personal Effort Requirements (In Hours) Alexander Jason James Matthew Task Name Beecher Chose Kopaska Treska Total Hours Select Signs 5 5 5 4 19 Select LEDs 4 20 3 4 31 Determine Electrical 40 42 43 42 167 Parameters Select Solar Panel, Battery, 35 37 39 37 148 and other Hardware Design Circuit 15 17 15 17 74 Plan Construction 21 22 23 22 88 Construct Prototype 32 34 35 34 135 Test and Refine Prototype 43 48 46 47 184 Finalize Prototype 10 14 13 15 52 Documentation 35 18 19 17 89 Poster 12 11 11 12 46 Software Development 65 71 74 69 279 Website Creation 8 2 2 2 14 Updating Website 10 4 4 2 20 Total Hours 335 345 332 324 1343

49 Table 3 – Final Personal Effort Requirements (In Hours) Task Name Alexander Jason Chose James Matthew Total Hours Beecher Kopaska Treska Select Signs 5 5 5 4 19 Select LEDs 4 20 3 4 31 Determine 34 33 42 37 146 Electrical Parameters Select Solar 35 37 39 37 148 Panel, Battery, and other Hardware Design Circuit 8 9 11 9 37 Plan 17 15 21 16 69 Construction Construct 30 23 35 28 116 Prototype Test and 32 33 (software) 35 31 131 Refine Prototype Finalize 7 5 (software) 11 3 26 Prototype Documentation 18 18 17 19 72 Poster 6 6 6 5 23 Software 16 39 21 22 98 Development Website 15 2 2 2 21 Creation Updating 12 1 1 1 15 Website Total Hours 239 246 249 218 952

4.1.2 Other Resource Requirements Table 3 displays the estimated time and dollar costs for major product resources. Some items, such as the actual road signs and the solar panel can be obtained with minimal or no cost to the design team through the DOT. Other items are unable to be acquired for free, but estimated costs are shown. Many LEDs are obtained through sampling from major parts manufacturers, but some clusters of LEDs must be purchased. Hours and dollars spent on the project are subject to future variables in the project, but can be accounted for if or when they occur.

50 Table 4 – Original Time and Capital Cost for Major Resources Item Team Hours Other Hours Cost Signs 4 0 Donated LEDs 54 0 $25.00 Battery 74 0 $50.00 Solar Panel 74 0 Donated Project Poster 46 0 $75.00 Software 279 0 None Mounting Hardware 123 0 $50.00 Total 654 0 $200.00

Table 4 displays the revised time and dollar costs for major product resources.

Table 5 – Revised Time and Capital Cost for Major Resources Item Team Hours Other Hours Cost Signs 18 0 Donated LEDs 31 0 $80.00 Battery 74 0 Donated Solar Panel 74 0 Donated Project Poster 46 0 $25.00 Software 279 0 None Mounting Hardware 123 0 $50.00 PV Charge Controller 16 0 $87.50 Flasher/dimmer 15 0 $57.00 Seven Day 8 0 $120.00* Programmable Timer Single Flasher Unit 6 0 $21.00* Total 690 0 $299.50 *Parts not used in prototype implementation.

Table 6 – Final Time and Capital Cost for Major Resources Item Team Hours Other Hours Cost Stop Sign 8 0 Donated LEDs 13 0 $80.00 Battery 25 0 Donated Solar Panel 28 0 $20.00 Project Poster 21 0 $25.00 Software 24 0 None Mounting Hardware 10 0 $40.00 PV Charge Controller 12 0 $87.50 Flasher/Dimmer 10 0 $57.00 Total 151 0 $334.50

51 4.1.3 Total Estimated Costs with Labor Table 5 shows the total estimated cost of the project with the addition of team labor costs. The labor cost was figured at $11.00 per hour.

Table 7 – Original Project Cost Estimates Item Cost Without Labor Cost With Labor Parts and Material Items: a. Signs Donated Donated b. LEDs $25.00 $25.00 c. Battery $50.00 $50.00 d. Solar Panel Donated Donated e. Software $75.00 $75.00 f. Mounting Hardware $50.00 $50.00 Subtotal $200.00 $200.00 Labor at $11.00 per hour: a. Alex Beecher $3707.00 b. Jason Chose $3795.00 c. Jim Kopaska $3883.00 d. Matt Treska $3762.00 Subtotal $15147.00 Total $15347.00

Table 6 shows the revised total cost of the project with the addition of team labor costs. The labor cost was figured for total hours at $11.00 per hour.

Table 8 – Revised Project Cost Estimates Item Cost Without Labor Cost With Labor Parts and Material Items: a. Signs Donated Donated b. LEDs $80.00 $80.00 c. Battery Donated Donated d. Solar Panel Donated Donated e. Software None None f. Mounting Hardware $50.00 $50.00 g. Flasher/dimmer $57.00 $57.00 h. PV Charge Controller $87.50 $87.50 Subtotal $274.50 $274.50 Labor at $11.00 per hour: a. Alex Beecher $3685.00 b. Jason Chose $3795.00 c. Jim Kopaska $3652.00 d. Matt Treska $3564.00 Subtotal $14696.00 Total $14970.50

52 Table 9 – Final Project Cost Estimates Item Cost Without Labor Cost With Labor Parts and Material Items: a. Signs Donated Donated b. LEDs $80.00 $80.00 c. Battery Donated Donated d. Solar Panel $20.00 $20.00 e. Software None $264.00 f. Mounting Hardware $40.00 $40.00 g. Flasher/Dimmer $57.00 $57.00 h. PV Charge Controller $87.50 $87.50 Subtotal $284.50 $548.50 Labor at $11.00 per hour: a. Alex Beecher $2629.00 b. Jason Chose $2706.00 c. Jim Kopaska $2739.00 d. Matt Treska $2398.00 Subtotal $10472.00 Total $11020.50

4.2 Project Timeline This section will outline the project and deliverables schedules. It also contains charts which map out the timeline involved in this section.

4.2.1 Project Schedule Table 7 shows the general scheduling for work areas of the project. The sections were scheduled based upon due dates shown in Table 8, and are subject to alteration depending upon project progress or other variables. Little to no work occured during Thanksgiving break (week of 21 Nov), Christmas break (19 Dec through 9 Jan), and Spring break (week of 13 Mar).

4.2.2 Deliverables Schedule Tables 7 and 8 show the due dates for major points throughout the project process. Some dates are estimated, such as a presentation time, since the second semester schedule is not currently set. Future dates were estimated based upon the current planning for Dec05 Senior Design projects.

53 Table 10 – Project Schedule Through End of Project

54 Table 11 - Updated Project Schedule

55 Table 12 - Final Project Schedule

56 Table 13 – Deliverable Schedule Through End of Project

57 Table 14 – Revised Deliverables Schedule

58 Table 15 – Final Deliverables Schedule Through End of Project

59 Section 5 – Closure Material The closure material contains the project evaluation, commercialization, recommendation for additional work, lessons learned, risk management, project team information, closing summary, references, and appendices.

5.1 Project Team Information The project team information contains the client information, faculty advisor information, and student team information.

5.1.1 Project Evaluation Evaluation of the project was based on the completion of the milestones set forth at the beginning of the project. The group rated the success of each task in one of the following ways: greatly exceeded, exceeded, fully met, partially met, not met, not attempted. Below is the original list of milestones and proposed dates.

Tues. Sept 27, 05 Select LED to be used (voltage, power, color, diameter) and LED/sign Fri. Oct 14, 05 Determine worst case available sun for charging Tues. Oct 25, 05 Select solar panel/battery to be used Tues. Nov 1, 05 Select timer for school sign Tues. Nov. 15, 05 Design electrical circuits Tues. Dec 6, 05 Determine construction plan/parts Thur. Dec 8, 05 Order all pieces, including all donated parts Fri. Dec 9, 05 End project design Tues. Feb. 14, 06 Construction of LED mounting completed Tues. Feb. 28, 06 Construction of control box/solar mounting completed Tues. Mar. 6, 06 Construction of harness from controls to LED’s done Tues. Apr 18, 06 Testing completed

60 LED selection was fully met. This decision was made on schedule and met the full requirements for its application in our design. These parts were also ordered and received in a timely manner.

Obtaining worst case solar data was fully met. This data was collected on schedule from the NREL website and has been completely loaded into the software tool for use in the calculations section.

Battery and solar cell selection was partially met. A solar cell was obtained but did not meet the original schedule. A battery was selected but not obtained due to financial restrictions. A similar battery was lent to the group for use during the project. Decisions were made as to the type and specifications of these components when implemented in mass production.

Timer selection for the school sign was exceeded. A multi-functional timer was located that allowed for numerous programmed events. The selected model was a perfect fit for the project and gave even more options than the group originally expected.

Design electrical circuits was fully met. All circuits were developed on time and have since been tested and implemented.

Determine construction plan/parts was exceeded. The entire construction plan and list of parts to order was completed before the due date. This was a huge success for the group and made the entire project run much more efficiently.

Part ordering was partially met. Some difficulties were encountered during the ordering process. Incorrect parts were sent by the distributor in one instance and the schedule for ordering was not fully met. Donated parts were a huge success and made the implementation go very smoothly.

61 End product design was fully met. A design report was completed on schedule and turned in to the appropriate entities. The resultant grade was very favorable which added to the success of this milestone.

Construction of LED mounting was partially met. The finish date for this milestone was not met. This was due to back ordering of parts and inability to obtain a rivet gun. Construction was eventually completed once all of these items were obtained.

Construction of control box and solar mounting was greatly exceeded. An excellent design was created and implementation worked flawlessly. The group was very pleased with the outcome of this construction and feel that the final result was considerably better than anticipated.

Construction of harness for electrical connections was fully met. Design for wiring was implemented and proven successful. Components are installed and protected as required for the application.

Testing was fully met. This testing was proven very successful but did not exceed expectation due to the limitation as to where testing could be conducted. It would have been favorable to have done testing in a variety of locations, but this was obviously infeasible at this time.

At this point all milestones have been met and have not hindered the progress of the project as a whole. A few extra milestones were developed along the way regarding the software aspect of the project. As a whole the software milestones were constantly changing which led to difficulty in scheduling. The overall expectations for the software were greatly exceeded. The end product is much more accurate and user friendly than was ever expected by the group.

62 Below is a table representing the relative importance of each task and the determined rating for the project team. It was deemed that any percentage over 70% would be satisfactory and anything over 80% would be considered a success.

Table 16 – Project Evaluation Ratings Task Importance Rating Score Select LED's 5 9 45 Worst Case Scenario 8 9 72 Select Solar Panel 7 7 49 Select Battery 5 6 30 Select Timer 3 10 30 Design Electrical Circuits 9 9 81 Determine Constructino Parts 7 9 63 Order Parts 9 6 54 End Product Design 10 9 90 LED mountings 4 8 32 Component Construction 3 10 30 Harness Construction 3 9 27 Testing Completion 7 9 63

Total Possible Points 800 Points Earned 666

Percentage 83.25%

5.1.2 Commercialization

There are no plans for commercialization at this time. Before this could be done it would have to be certified by the DOT. Some estimates regarding the cost to produce such a sign include parts and labor. The parts for this product have a combined price of just less than $250. Labor requirements are based on a proven design and parts on hand. Physical construction could be done by one individual in 4 hours. If labor rates were averaged to $11 per hour this would have an added cost of $44. Total cost to build the sign is then just short of $300.

A potential selling price for the product would be somewhere between $350 and $400. This number would vary based on number of signs ordered and market

63 analysis. The most noteworthy customer would be the DOT. It is also conceivable that a private organization such as a large business in a high traffic area may be interested in installing such a piece of equipment.

5.1.3 Recommendation for additional work

There are very few recommendations for additional work. The end product is very accurate and effective. Some ideas for improvement may be in broader testing. It would be beneficial to construct and test the product in various locations throughout the continental 48 states. Such testing would further validate any assumptions made regarding operability of the product in varying climates and regions.

Another suggestion may be increasing the technology of the product. This could include wireless communication options for controlling programming and monitoring operational status. Adding such technologies would allow the end user to better monitor the product and ensure that it is working reliably at all times.

5.1.4 Lessons Learned

These lessons were based on 5 separate areas of evaluation. These are analyzed below with descriptions of the items to which they refer.

 What went well Physical construction Testing Team interaction Circuit design Documentation Software design

64  What did not go well Parts acquisition Software error checking Reporting

 What technical knowledge was gained Excel spreadsheet features Solar energy conversions Power calculations Photovoltaic properties

 What non-technical knowledge was gained Time management Project management Client interaction Budget planning Report writing Traffic regulations

 What would be done differently if project were repeated Start software design earlier Order parts at an earlier date Create small scale instead of full scale prototype Implement a different type of sign for prototype

5.1.5 Risk and Risk Management

This section lays out the risks that were associated with the project. This includes both anticipated and unanticipated risks as well as how they effected the overall outcome of the project.

 Anticipated risks and planned management o An obvious risk when working in groups is the loss of a team member. This was managed by keeping detailed records of work done and openly communicating all decisions made on an individual basis o Other risks are the failure of a technological approach or inability to implement a selected technology. This was managed by carefully selecting the technologies to be used and testing them on an individual basis prior to full scale implementation.

65  Anticipated risks encountered o None of the anticipated risks were encountered  Unanticipated risks encountered o Budget restrictions affecting selection of components o Illness keeping team members from attending all team meetings o Scheduling conflicts o Computer trouble causing loss of completed work  Resultant changes in risk management based on unanticipated risks o Continuous saving of information and backing up files to eliminate future loss of data o Increased communication between team members regarding work completed o Set specific meeting times each week that every member knew would work and planned around that time

5.1.6 Client Information Senior Design Department of Electrical and Computer Engineering Iowa State University Ames, IA 50011

5.1.7 Faculty Advisor Information John Lamont Dept. of Electrical and Computer Engineering Professor 324 Town Engineering Ames, IA 50011-3230 Office Phone: 515-294-3600 Fax: 515-294-6760 [email protected]

66 Ralph Patterson III Dept. of Electrical and Computer Engineering Assistant Professor 326 Town Engineering Ames, IA 50011-3230 Office Phone: 515-294-2428 Fax: 515-294-6760 [email protected]

5.1.8 Student Team Information Alexander Beecher Electrical Engineering 517 Hayward Ave. Ames, IA 50010 563-343-1404 [email protected]

Jason Chose Electrical Engineering 1316 S. Duff #15 Ames, IA 50010 515-292-3565 [email protected]

James Kopaska Electrical Engineering 415 Strawberry Lane Ames, IA 50010 515-290-1828 [email protected]

Matthew Treska Electrical Engineering 2921 Woodland St. Apt. 2 Ames, IA 50014 515-708-0559 [email protected]

67 5.2 Closing Summary

This project was created to assess the visibility of standard street signs in fast- moving traffic or low visibility areas. Using LEDs, a solar panel, a rechargeable battery, and control circuits, the project will outfit a selection of street signs in order to enhance their visibility in the aforementioned areas of use.

The group approached this problem in much the same way it originally planned using the components listed above. In addition to the implementation of a street sign that is solar powered with flashing LEDs, a software package was created. This software allows a prospective customer to select the features of the sign desired and in turn receive a detailed part list of what type and size components must be ordered.

It Is the belief of the group that the combination of a reference material to ease ordering and sizing along with a physical design that is reliable and efficient the afore mentioned problem has been dealt with successfully. Installation of such signs will certainly increase the awareness of approaching drivers as to the risks that await them.

68 5.3 References LED - wordnet.princeton.edu DOT - wordnet.princeton.edu

Figure 1 – http://www.fpm.iastate.edu/maps/ Timer Module – http://www.artisancontrols.com/products/4950.htm Flasher/Dimmer Module - http://www.theledlight.com/pdf/controls/flasher_auto_dimmer.pdf DF Flasher Module – http://www.amperite.com/Uploads/df%20flasher.PDF PV Controller Module – http://www.powerstream.com/ LED Module – http://www.sunbriteleds.com/ Sample Battery from calculations - http://www.windsun.com/Batteries/Concorde.htm

69 APPENDIX A PV CHARGE CONTROLLER (courtesy of powerstream.com)

70 71 72 73 74 75 76

77 78 APPENDIX B FLASHER DIMMER MODULE (courtesy of theledlight.com)

79 80 81 APPENDIX C DF FLASHER MODULE (courtesy of amperite.com)

82 83 84 85 86 APPENDIX D TIMER MODULE (courtesy of artisancontrols.com)