Speaker Timing System for the Western Protective
Relay Conference
Prepared By: Team Time’s UP!
Team Members :
Jesse Rebeck
Hugh Roberts
Frank Gonzales
Tim Montoya
Department of Electrical and Computer Engineering, University of Idaho
Submitted To :
Kelly Newell: WSU Center for Distance and Professional Education
Dave Angell
Brian Johnson
May 5, 2006
Time’s UP! 2
Executive Summary
This project was initiated by the WSU Center for Distance and Professional Education.
Our team has been commissioned to design, develop, build, and test two sets of a two-terminal
speaker timing system. These systems will be used at the Western Protective Relay Conference,
which is held annually in Spokane, Washington. They will aid the moderators in the task of
keeping the dual presentation sessions synchronized and on time.
The main challenge of this project will be completing the development and testing phase
by the deadline of October 13th . We have generated a Bill of Materials for the components we
will need, and we plan to purchase all components before the summer intermission so that they
will be ready and available for integration in September. The Bill of Materials satifies our
allotted budget, which includes supplemental funding acquired through the University of Idaho.
The total cost for the project is estimated to be $1567.
The main factors considered when choosing system components were minimum cost,
optimum performance, development time, and available support. The system requires wireless
communication between the moderator and speaker stations. A 900MHz-carrier signal was
chosen because it will avoid the interference associated with cell phones and WIFI networks.
Wireless communication will be achieved with MaxStream Zigbee wireless receiver/transmitter
modules. The Rabbit microcontroller was chosen because it is known to be reliable and robust.
Also, support for Rabbit components is available through the U of I Electrical Engineering
faculty. The moderator stations will each include a radio-controlled clock so that the
simultaneous presentations can be synchronized.
Time’s UP! 3
Table of Contents
Table of Figures............................................................................................................................. 4
1.0
INTRODUCTION............................................................................................................. 5
1.1
1.2
1.3
1.4
1.5
2.0
2.1
2.2
2.3
2.4
2.5
BACKGROUND............................................................................................................................................................. 5
PROBLEM /N EED ......................................................................................................................................................... 5
S TATEMENT OF PURPOSE......................................................................................................................................... 5
OBJECTIVE .................................................................................................................................................................. 5
METHODS .................................................................................................................................................................... 6
PROBLEM DEFINITION ............................................................................................... 6
CLIEN T N EEDS ............................................................................................................................................................ 6
CONSTRAINTS ............................................................................................................................................................. 7
S PECIFICATIONS ......................................................................................................................................................... 7
D ELIVERABLES ........................................................................................................................................................... 7
D ESCRIPTION/FUNCTIONALITY OF THE S PEAKER TIMING S YSTEM .............................................................. 7
2.5.1 Example....................................................................................................................... 8
3.0 CONCEPTS ............................................................................................................................. 9
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
4.1
4.2
WIRELESS TRANSMITTER / R ECEIVER CONCEPTS CONSIDERED ................................................................... 10
WIRELESS TRANSMITTER / R ECEIVER CONCEPTS S ELECTION...................................................................... 10
USER INTERFACE CONCEPTS CONSIDERED ....................................................................................................... 10
USER INTERFACE CONCEPTS S ELECTION.......................................................................................................... 11
CURRENT TIME CLOCK CONCEPTS CONSIDERED ........................................................................................... 11
CURRENT TIME CLOCK CONCEPTS S ELECTION............................................................................................... 13
LCD AND S EVEN S EGMENT D ISPLAY CONCEPTS S ELECTION....................................................................... 13
POWER CONVERSION CONCEPTS S ELECTION................................................................................................... 13
MICROCONTROLLER CONCEPTS S ELECTION.................................................................................................... 14
SYSTEM ARCHITECTURE ........................................................................................ 14
MECHANICAL ARCHITECTURE............................................................................................................................. 14
ELECTRICAL ARCHITECTURE............................................................................................................................... 14
4.2.1
System Components ............................................................................................ 14
4.2.2
Interface Designs Considered ............................................................................ 16
4.2.3
Interface Design Selection .................................................................................. 17
5.0
ECONOMIC ANALYSIS .............................................................................................. 17
6.0
FUTURE WORK ............................................................................................................ 18
6.1
6.2
WORK SCHEDULE.................................................................................................................................................... 18
WORK BREAKDOWN S TRUCTURE........................................................................................................................ 18
Time’s UP! 4
List of Figures
Figure 1. Display of Master and Slave Terminals at First Warning Time...................................... 8
Figure 2. Display of Master and Slave Terminals at Second Warning Time ................................. 9
Figure 3. Display of Master and Slave Terminals when the Countdown Timer reaches Zero ....... 9
Figure 4. Numbered Keypad for the Master Station..................................................................... 11
Figure 5. Pictures of the Components for a Radio-Controlled Clock ........................................... 12
Figure 6. Commercially Made Radio-Controlled Clock............................................................... 12
Figure 7. A typical voltage regulator circuit. The DC input voltage is taken from the output of a
wall transformer. ........................................................................................................................... 14
Figure 8. System Component Interaction ..................................................................................... 15
Figure 9. Master Station and Slave Station using Arrows to Input Data ...................................... 16
Figure 10. Master Station and Slave Station using the Numbered Keypad to Input Data............ 16
Figure 11. Budget Allotment ........................................................................................................ 17
Time’s UP! 5
1.0 INTRODUCTION
1.1
Background
The Western Protective Relay Conference is an educational forum for the presentation and
discussion of broad and detailed technical aspects of protective relaying and related subjects.
The conference is held annually in Spokane, Washington in the month of October and about 450
people attend from around the world. This forum allows participants to demonstrate and apply
advanced technologies that prevent electrical power failures. Speakers are invited to present
papers selected by a group of protective relaying experts.
1.2
Problem/Need
A problem has developed with speakers exceeding allotted time. Since the audience consists
primarily of professional engineers and consultants, presentations that go overtime can cause
attendees to be late to other presentations, missing valuable information. The annual conference
is in need of a timing system that indicates to a moderator and speaker how much time is left in a
presentation.
Our team has the opportunity to design and build two sets of a two-terminal speaker timing
system. The master terminal, or moderator station, is programmed to regulate the time of the
presentation. The slave terminal, or remote station, displays the remaining time of the
presentation for the speaker to see. The system will decrease the likelihood of a speaker
overrunning his/her allotted time and help the conference stay on schedule. A speaker timing
system is necessary because adhering to the time schedule will improve the efficiency of the
conference. Overall, this project will help the WPRC run more smoothly.
1.3
Statement of Purpose
Lecture speakers overrunning their allotted presentation time is a common issue at conferences.
This report presents the proposed speaker timing system tha t will be designed, built, and tested to
meet the needs of the WPRC. The primary goal of the system is to inform guest speakers of their
remaining presentation time and prevent time limits from being exceeded. The conference will
benefit from the synchronization achieved with the aid of a moderator controlled speaker timing
system for years to come.
1.4
Objective
The objective of this project is to provide the WPRC with a speaker timing system by October of
2006. We have performed research that confirms the feasibility of the speaker timing system and
aids us in the development of a prototype. The speaker timing system will be designed, built, and
tested to meet the specifications listed in section 2.3. In addition, we will provide the WPRC
with technical documentation and a user manual.
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1.5
Methods
The design for the speaker timing system will be done in collaboration with the ECE Capstone
Design two-semester course sequence. The first semester will include the design and
documentation of the speaker timing system. The second semester will include the building,
testing, and delivery of the system. Research will be conducted at the University of Idaho
library, online, through various application notes, and on-site if necessary. Faculty aid will be a
dominant resource for this project. Work will be done in a team of four. We will utilize CAD
drawings as well as research from textbooks and credible internet sites in the areas of electronics,
wireless communication, radio frequency timing mechanisms, Dynamic C programming
language, and power conversion. The design team will also be in constant communication with
the client. He will be notified of our progress so that he can provide feedback when necessary.
2.0 PROBLEM DEFINITION
2.1
Client Needs
The needs of our client are divided into three categories. Below is a list of the client’s needs:
1) Functionality
• Two identical units consisting of a master station controlled by the moderator and a
remote station in front of the speaker
• Session length and warning times programmable at master terminal
• Time indicator warning lights for speaker on remote station
• System suited for dual conference sessions
• Stand alone units
• Usable at alternate conference locations
2) Communication
• Wireless communication between the master and slave stations
• Communication range to up to 50 feet between the master and slave stations
• Synchronized time-of-day clocks on both master stations to display the time-of-day to the
moderator. The clocks are synchronized to the standard WWVB signal
3) Physical
• Economical System
• Long Product Life
• Durable and Rugged
• Compact, Lightweight, and Portable Size
• Powered by 120 volts AC
Time’s UP! 7
2.2
Constraints
The constraints for the speaker timing system are listed below:
•
•
•
2.3
Budget - Sponsor would like to build each unit for $300.
Time - Deadline of completion is October 2006.
Station Size - Master Station is approximately 12x8 inches, remote station is
approximately 6x8 inches.
Specifications
The specifications for the speaker timing system are listed below:
•
•
•
•
•
•
•
•
•
•
•
2.4
Product life >= 20 years
Durability – can withstand 4 ft drop
Unit price <= $300
Wireless Communication range >= 50 ft
Master clock synchronized to GPS or WWVB
Remote station base area <= 48 in2
Master station base area <= 96 in2
Master/slave weight <= 5 lb
Acceptable power supply - standard 120 VAC power outlet
Time counter accuracy >= 1ms
Time to program <= 1 minute
Deliverables
The following is a list of items that we will deliver to WSU no later than the second week of
October of 2006:
1) Two speaker timing system units. Each unit consists of a master station and a slave
station. The stations will conform to the description of the system in 2.5.
2) Technical documentation that includes specifications, diagrams, and schema tics.
3) User manual with detailed instructions on operation of the speaker timing system.
2.5
Description/Functionality of the Speaker Timing System
The master terminal consists of programming buttons, a display window for the countdown
timer, display for the current time clock, and three Light Emitting Diodes (LED’s). The
presentation length (hours: minutes: seconds) and two indicator LED times are programmed at
the moderator station. The current time display is a radio-controlled clock that is automatically
Time’s UP! 8
updated by the 60 kHz WWVB radio signal. This will effectively synchronize the two units since
both moderator stations will display an identical time of day. The slave terminal will consist of a
7-segment display for the countdown clock and three LED’s (red, yellow, and green) for warning
indicators.
During the presentation the master terminal communicates with the slave terminal to keep the
countdown timers synchronized. When the presentation is started the green LED switches “on”
(LED’s are visible on both stations). After the first warning time is reached, the master terminal
switches the green LED “off” and the yellow LED “on”. When the second warning time is
reached the yellow light begins to blink “on” and “off”. When the countdown timer reaches zero
the yellow LED switches “off” and the red LED switches “on”.
2.5.1 Example
Here is an example of how the speaker timing system functions, given a presentation length of
60 minutes.
1) The moderator programs 60 minutes for the presentation length (using the keypad), 5
minutes for the solid yellow warning light, and 1 minute for the blinking yellow warning
light.
2) The START button on the master terminal is pressed when the presentation begins. The
master terminal communicates the amount of remaining time with the slave terminal.
The countdown timers on both terminals begin counting down. The green LED’s on both
terminals switch “on”.
3) When the countdown clock reaches the first warning time the yellow LED switches “on”
and the green LED switches “off”. For this example, the yellow LED turns on when the
speaker has five minutes remaining.
Master Terminal
Slave Terminal
00:05:00
00:05:00
9:55:00
Figure 1. Displ ay of Master and Slave Terminals at First Warning Time
Time’s UP! 9
4) When the countdown clock reaches the second warning time, the yellow LED begins
blinking “on” and “off”. For this example, the yellow LED begins blinking when there is
one minute remaining.
Master Terminal
Slave Terminal
00:01:00
00:01:00
9:59:00
Figure 2. Display of Master and Slave Terminals at Second Warning Time
5) When the countdown clock reaches zero, the red LED will switch “on” and the yellow
LED will switch “off”. The timer will begin counting upward if the speaker goes
overtime.
Master Terminal
Slave Terminal
00:00
00:00
9:59
Figure 3. Display of Master and Slave Terminals when the Countdown Timer reaches Zero
6) When the speaker ends the presentation the moderator presses the “Stop/Reset” button on
the master station to stop the countdown timers and switch “off” the LED’s on both
terminals.
3.0 CONCEPTS
The speaker timing system design will include electrical and mechanical aspects. The electrical
aspects will include the microcontroller, time-of-day clock, LED lights, LCD display, 7-segment
display, wireless transmitter/receiver, power conversion, and user interface. The mechanical
aspects will include the housing unit to encase the electrical components.
Time’s UP! 10
3.1
Wireless Transmitter/Receiver Concepts Considered
The master and slave unit will communicate via a wireless serial link. The wireless options that
have been considered are transparent. This means that to the master and slave, they will appear
as a wire. Using this kind of wireless allows us to utilize the serial libraries of the Rabbit
microcontroller to communicate with the slave unit. This will help keep development time
down.
Three different options have been considered for use for wireless transmission. All three of the
options are OEM components that can be soldered on to the board. The first option, the Sena
unit, uses Bluetooth technology for wireless communication. This is a 2.4GHz technology which
has potential for interference with WI-FI networks in the hotel. The second option is the XBee
ZigBee RF module from MaxStream. This is a low cost low power serial-to-wireless module
that operates in the 2.4GHz range. The XBee also has the WI-FI interference issues. It main
advantage is cost, as it comes in at $19 a module where as the Sena comes in at $55. The third
option is also from Maxstream and is the XCite RF module. The XCite module operates in the
900 MHz range and has less chance for interference. However, the cost is about twice that of the
XBee module at $40 a module. All of these units will require zero-configuration by the end user.
3.2
Wireless Trans mitter/Receiver Concepts Selection
At the conference, the communication between the master and slave stations must have very
little to no interference. Since the XCite module operates at 900 MHz and has less chance for
interference, we have selected the XCite RF module for the wireless solution.
3.3
User Interface Concepts Considered
The moderators will need to quickly learn how to use the speaker timing system and how to
accurately program the presentation length and the warning times into the master station.
Therefore, the user interface will be intuitive and user friendly. We have considered two design
options for the user interface. Both options will include a Start/Send button to begin the
countdown timer and a Stop/Reset button to stop the countdown timer and reset the system. The
Stop/Reset button will also be used to ensure that the master station is communicating with the
slave station.
Option 1: Numbered Keypad
The first option is to use a numbered keypad. The numbered keypad is an easy way to enter
timing information. The moderator will enter the presentation length and warning times in an
hhmmss format. These parameters will be displayed in the LCD window so the moderator can
make sure they are correct. Figure 4 shows what the keypad will look like.
Time’s UP! 11
Figure 4. Numbered Keypad for the Master Station
Option 2: Arrow Keys
Arrow keys will be used to select timing parameters from a menu that need to be programmed.
This is done by using the arrow keys to scroll and select the appropriate number of time. Using
the arrow keys will take longer to program the timing parameters and will also be more difficult
to learn when learning to program the master terminal.
3.4
User Interface Concepts Selection
The numbered keypad option would be much easier for a moderator to program timing
information into the master station. Although more buttons will be required to connect to the
circuitry, it will be a more user-friendly product.
3.5
Current Time Clock Concepts Considered
To allow the master terminal to be synchronized to the current time, a clock will be installed into
the master station that will be viewable to the moderator. This will allow the moderator to begin
the presentations on time. Below are the types of clocks considered.
Option 1: Radio-Controlled Clock
A radio-controlled clock has a miniature radio receiver inside it that is permanently tuned to
receive a 60 KHz radio signal. The signal is broadcast from NIST Radio Station WWVB which
is located near Fort Collins, Colorado. The signal includes a time and date code. When the
clock receives and decodes the signal, it will synchronize its own clock to the radio’s signal, thus
ensuring the clock has the current time.
There are two alternatives for the radio controlled clock. The first alternative is to purchase
separate components to build the clock and integrate it with the microcontroller in the master
station. Diagrams of the parts for the clock are shown in Figure 5.
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Figure 5. Pictures of the Components for a Radio-Controlled Clock
There are three components for a radio-controlled clock: the decoder, antenna, and the receiver.
The advantage of having the clock integrated into the main microcontroller is the countdown
timer may be more accurate. The disadvantage is that these components are prohibitively
expensive. Also, the antenna would stick out of the housing unit, which would cause the system
to be less durable.
The second alternative is to purchase a commercially- made radio-controlled clock for each
master station and install them into the master station. Figure 6 shows a picture of one of these
types of clocks.
Figure 6. Commercially Made Radio-Controlled Clock
The advantage of these clocks is they are inexpensive, costing about 8 times less than alternative
1. In addition, the circuitry is already built and tested, including the display. The disadvantage
is power regulation. Small clocks like the one shown in Figure 6 run on batteries, so we would
need to integrate the clock into the power supply of the master terminal. Additional research will
be needed to complete that task.
Option 2: GPS
GPS clocks use the satellites orbiting the earth to synchronize the time. The advantage of GPS
clocks is the time is more accurate than radio-controlled clocks. The disadvantage is they are
very expensive and they do no t work very well inside buildings. Most systems that use GPS
Time’s UP! 13
timing inside a building will have a GPS server that gets the timing signal from a satellite dish
that is installed on the roof of the building. The server then sends a signal to all the GPS clocks
to synchronize the time. The GPS clock for the speaker timing system is not feasible.
3.6
Current Time Clock Concepts Selection
The selection of the clock was based mainly on price. Since the commercially made radiocontrolled clock alternative is so inexpensive, we have selected that alternative and will install it
into the housing unit. We will research the best method to integrate it into the power supply of
the system.
3.7
LCD and Seven Segment Display Concepts Selection
The LCD we have selected will be attached to the master terminal. It will be 4 lines in width and
20 characters in length. The LCD will display a list of the timing parameters that the moderator
has programmed. During the presentation, it will display the countdown timer.
The 7-segment display will be attached to the slave station to display the countdown timer. They
will be large enough so the speaker can easily see the countdown timer and they will be in a
pleasing color, such as green or blue.
3.8
Power Conversion Concepts Selection
The units will be powered by a wall transformer that plugs into a standard 120 VAC power
outlet. The wall transformers step down the voltage and rectify the AC to DC. These units
deliver a rated voltage at a rated current load. The benefits of using a wall transformer are as
follows:
1) They offer electrical isolation from the power outlet. This greatly increases electrical
safety for both the user and the hardware.
2) The physical space and weight required for a power adapter is taken out of the
master/slave units, which enables them to be smaller and lighter.
3) The DC voltage required by the subsystems in the master/slave units is directly delivered.
The trade-off with the wall transformer is that the majority of economical units have little-to- no
voltage regulation. This means that the output voltage varies with the current load. In order to fix
this problem, a simple regulator circuit needs to be implemented. The circuit that will be used is
a voltage regulator IC with filter capacitors at the input and output of the IC. This circuit
provides low noise, low voltage ripple, and a constant voltage level that is independent of load.
Additional voltage levels can be acquired by adding addition voltage regulator ICs. Figure 7
shows a typical regulator circuit.
Time’s UP! 14
Figure 7. A typical voltage regulator circuit. The DC input voltage is taken from the output of a wall
transformer.
3.9
Microcontroller Concepts Selection
We have selected the Rabbit microcontroller to control the master and slave stations. The
advantage to the Rabbit microcontroller is:
1) It will perform all the necessary functions to control the speaker timing system.
2) It is known and used at the University of Idaho so we will be able to obtain assistance
from professors, if needed.
3) The development software for the processor is already installed in the Engineering lab at
U of I, so we will not need to purchase that software.
4.0
4.1
SYSTEM ARCHITECTURE
Mechanical Architecture
The electrical components of the speaker timing system will be encased in a housing unit made
of thick, durable plastic that will help absorb small forces. We have contacted the mechanical
shop at U of I to ensure that they could build a housing unit when are ready for one. Before a
unit can be built, we will need to put together all of the electrical components to determine the
housing size we will need.
4.2
Electrical Architecture
4.2.1 System Components
The design of the speaker timing systems will include seven main components that are listed
below.
Time’s UP! 15
1)
2)
3)
4)
5)
6)
7)
8)
Microcontroller to control the countdown timer and the warning lights
7-segment display to display the countdown timer on the slave station
LCD to display the countdown timer on the master station
Red, yellow, and green LED’s for the warning lights
Wireless transmitter/receiver to enable the master and slave terminals to communicate
Power converter to convert the 120 volts AC to the required DC power on both stations
Current time clock that automatically synchronizes with WWVB
Housing unit that consists of programming buttons, display windows, and space to
enclose the electronic circuitry (microcontroller, LED’s, 7-segment display, LCD,
wireless transmitter/receiver, clock, power converter)
Figure 8 is a block diagram that illustrates the component interaction and flow. Timing
parameters are programmed into the microcontroller by using the keypad. The microcontroller
then controls the other components by displaying the countdown timer on the LCD and 7segment display, turning the LED’s on and off at the specified times, and sending the correct
signals to the transmitter/receiver to communicate with the other station.
Figure 8. System Component Interaction
Time’s UP! 16
4.2.2
Interface Designs Considered
Option 1
The first option is to use arrow buttons to program the master terminal. The arrow buttons will
allow the user to scroll through a menu on the LCD, selecting the timing parameter to program.
Figure 9 shows a diagram of the master and slave stations using the arrow buttons.
Figure 9. Master Station and Slave Station using Arrows to Input Data
Option 2
The second option uses buttons to select the timing parameter to program and then a keypad to
enter the timing parameters. Figure 10 shows a diagram of the master and slave stations using
the numbered key pad.
.
Figure 10. Master Station and Slave Station using the Numbered Keypad to Input Data
Time’s UP! 17
4.2.3
Interface Design Selection
The interface will allow the moderator to program the presentation length and warning times into
the master station. We want an interface that will be easy to use and learn. Option 2 is the best
solution to allow the moderator to quickly learn how to program and use the master station.
5.0 ECONOMIC ANALYSIS
Below is an analysis of the costs associated with the Speaker Timing System. Items in bold will
be funded through a grant awarded by the University of Idaho Electrical Engineering department
and will remain at U of I after project completion.
Item
Used for:
Unit Price
Quantity
Total Cost
RCM2020 Rabbit
Microcontroller
Controls the countdown timers and
LED switching
$39
4
$156
Development
Board
4 X 40 LCD Display
Microcontroller Development
and programming
Display window for master
stations
Countdown timer for slave
stations
Drive the LCD Displays
$130
2
$260
$50
2
$100
$30
2
$60
$10
2
$20
Encases electrical components
Wireless Communication
between master and slave
Wireless Development
$50
$55
4
4
$200
$220
$197
1
$197
Convert 120 Volts AC to
required DC voltage levels
Current time clock
Indicator warning lights
$30
4
$120
$30
$2
2
12
$60
$24
Input data buttons
Presentation of Project
$20
$60
1
1
$20
$60
Install and Test System in
Conference Center
36.5 cents a
mile
$200
$73
7-segment Display
LCD Display
Drivers
Housing Unit
Wireless
Transmitter/Receiver
Wireless
Development
Board
Power Converter +
Regulator Circuit
WWVB Clock
Large Warning Light
LED’s
Debounced buttons
Poster and
Presentation
Materials
Travel Costs
Total Cost
$1587
Figure 11. Budget Allotment
Time’s UP! 18
6.0 FUTURE WORK
6.1
Work Schedule
This point marks the end of the system integration stage of the project. The work that remains is
the detailed design phase, fabrication stage, validation stage, and delivery. During the detailed
design phase the team will completely draw out the system and specify how it will be built.
During this phase the parts will be ordered. Since the team will be leaving for summer break, we
will order the parts before the break begins.
When the fall semester commences, we will begin the fabrication phase in which the components
are integrated into the system. Since we need to have a completed working system by October,
building will begin immediately. We plan to have the system built by the end of September so
that we can spend the first week of October testing the system at the conference center. We will
test and debug the system before delivery to the sponsor.
After the system has been designed, built, tested, and delivered we will then focus on writing
technical documentation, a user’s manual, and a snapshot poster.
6.2
Work Breakdown Structure
A complete schedule is attached on the next page.