Optical Tape Measure



Optical Tape Measure

May04-30

Design Report

Faculty Advisors: Degang J. Chen

Aleksandar Dogandzic

Team Members: Nick Freese

Bruce Fu

Jason Thompson

Eugene Zimmer

Client: Senior Design

December 9, 2003

Table of Contents

List of Figures iii

List of Tables iv

List of Definitions v

Section 1- Introductory Materials 1

1.1 Abstract 1

1.2 Acknowledgement 1

1.3 Problem Statement 1

1.4 Operating Environment 2

1.5 Intended Users and Uses 2

1.6 Assumptions 2

1.7 Limitations 2

1.8 Expected End Product and Other Deliverables 3

Section 2- End-product Design 3

2.1 Approach Used 3

2.1.1 Design Objectives 3

2.1.2 Functional Requirements 3

2.1.3 Design Constraints 4

2.1.4 Technical Approach Considerations 4

2.1.5 Technical Approach Results 6

2.1.6 Testing Approach Considerations 6

2.1.7 Recommendations Regarding Project Continuation or Modification 6

2.2 Detailed Design 7

2.2.1 Design Overview 7

2.2.2 Timer Module 8

2.2.3 Transmitter Module 10

2.2.4 Receiver Module 11

2.2.5 Microcontroller with LCD 13

Section 3- Resources and Schedules 14

3.1 Resource Requirements 15

3.1.1 Personnel Time Requirements 15

3.1.2 Other Resource Requirements 16

3.1.3 Financial Requirements 17

3.2 Schedules 19

3.2.1 Project Schedule 19

3.2.2 Deliverables Schedule 20

Section 4- Closure Materials 21

4.1 Project Team Information 21

4.1.1 Client Information 21

4.1.2 Faculty Advisors Information 22

4.1.3 Student Team Information 22

4.2 Closing Summary 22

Section 5- References 24

Section 6- Appendices 25

Appendix A: TDC-GP1 Data Sheet 25

Appendix B: G4176-01 Datasheet 27

Appendix C: S8334 Datasheet 29

Appendix D: AD230-T05 31

Appendix E: Optical Tape Measure Testing Form 35

List of Figures

Figure 1: Time of Flight Block Diagram 7

Figure 2: TDC-GP1 8

Figure 3: Microprocessor TDC-GP1 Interface 9

Figure 4: IXLDO2SI Chip 11

Figure 5: First Semester Schedule 19

Figure 6: Second Semester Schedule 20

Figure 7: Deliverables Schedule 21

List of Tables

Table 1: Photodiode Constraints 13

Table 2: Original Personnel Time Requirements 15

Table 3: Revised Personnel Time Requirements 16

Table 4: Original Other Resource Requirements 16

Table 5: Revised Other Resource Requirements 17

Table 6: Original Financial Resources 18

Table 7: Revised Financial Resources 18

List of Definitions

• Beam pulse – a short burst of light emitted by a laser.

• Class 2 laser – a classification of laser where short exposure is not harmful to the human eye

• GPS mapping – a navigational system using satellite signals to fix the location of a receiver on or above the earth’s surface.

• Incident – falling upon or striking a surface

• Interference – confusion of a received signal due to the presence of noise or signals from two or more transmitters on a single frequency.

• I/O – Input/output

• Laser – light amplification by stimulated emission of radiation.

• LED – a semiconductor diode that converts applied voltage to light and is used in digital displays.

• LCD – Liquid crystal display

• Modulated beam – the strength of the laser is rapidly varied to produce a signal that changes over time.

• Optical – of, relating to, or utilizing light especially instead of other forms of energy.

• PIC – Peripheral Interface Controller from Microchip

• Range finding – Process of determining the distance to a desired object.

• Reflection – The return of light or sound waves from a surface.

• TDC – Time to digital converter

• Time of flight – the time it takes light to travel from the sensor to the target and return.

• µP – Microprocessor, a controller that is capable of receiving inputs and producing outputs based on its internal logic.

Introductory Materials

To begin this design report, the problem that the team has been working on over the course of the semester needs to be defined in detail. Thus, this section will outline what exactly the problem that the optical tape measure shall solve and what was considered in the design.

1 Abstract

Inexpensive ultrasonic tape measures are available that can only measure perpendicular distances to fairly large, flat surfaces. Complex environments make it nearly impossible to determine which surface corresponds to the measured distance. Determining the distance between any two designated spots and producing a model of a measured object are impossible with current ultrasonic tape measures.

The team is designing and implementing an optical tape measure that will measure the distance to any visible spot within its range. The point to which the distance is to be measured will be designated by a laser pointer. Designating an appropriate set of measurements will produce a model of a measured object. Distances up to 100 feet in length will have an accuracy of ± 0.5%.

2 Acknowledgement

There are no acknowledgements at this time in the project.

3 Problem Statement

Current ultrasonic tape measures are available that will measure a perpendicular distance up to fifty feet from the device. Pointing these devices to particular objects can become impossible in complex environments. A tape measure is needed that will measure the distance to any visible spot within its range. The small yet durable device will be able to measure the distance between any two distinct points and create a model with an appropriate set of measurements. This mobile device needs to measure distances up to 100 feet in length with 0.5% tolerance.

An optical tape measure will be designed to solve these problems. A laser will be used to designate the exact point of measurement. The device will run off of small batteries and be able to fit in the palm of the user’s hand. Several measurements shall be averaged in the device’s memory to increase the accuracy of the measurement. The average measured distance from the device to a designated object will be shown on the digital LED display.

4 Operating Environment

Wide arrays of operating environments exist for tape measures. The device will be exposed to many possible indoor and outdoor conditions. Precipitation and temperature changes are present in the countless environments where tape measures are used. Windy and dusty conditions should not significantly affect the reliability of the tape measure. The device may also be exposed to physical abuse such as dropping.

5 Intended Users and Uses

Several users currently use tape measures. The intended users include high school graduates that regularly use tape measures. A slight tutorial is needed to understand the multiple uses of the optical tape measure. A list of some more specific users may include construction workers, surveyors, and architects.

The intended uses cover a large variety of applications. Measurements can be taken from any visible point that sufficiently reflects an incident laser pulse. Applications may include general measurement, forestry, surveying, utility mapping, GPS mapping, mining, traffic engineering, accident investigation, ship docking, recreational sports, and industry.

6 Assumptions

The following is a list of assumptions regarding the design of the product:

• Users will know how to use a tape measure.

• Users will be physically able to use a tape measure.

• The object points to be measured are stationary.

• The reflecting surface will be sufficiently reflective.

• The reflecting surface will be nearly perpendicular to the incident pulse.

• Batteries will provide enough power for the device to operate.

• All required resources will be available when needed.

• All team members will be able to contribute enough time to complete the project.

Updates shall occur as the process continues.

7 Limitations

The following is a list of limitations imposed on the design of the product:

• Device must measure up to 100 feet.

• Accuracy must be within ± 0.5%.

• Dimensions must not exceed 6”x 8” x 3”.

• Cost of the prototype must be less than $355.

• Device must be easily portable.

• Device shall not weigh over 1 lb.

• The weather shall not significantly affect the accuracy of the device.

Updates shall occur as the process continues.

8 Expected End Product and Other Deliverables

The following is a description of the expected end product and the list of provided deliverables:

• A small, durable, lightweight optical tape measure. This will be the actual device that will obtain and calculate the measurements.

• A user’s manual. This will describe to the user how to operate the device.

• A maintenance manual. This will describe to the user how to properly care for the device.

• Test results. These will be the results from the prototype testing.

End-product Design

In order for the team to be successful with this project they will first need to determine technical, security, intellectual, and safety considerations. 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.

1 Approach Used

The following sections of the design report will cover the technical constraints and approaches that the team has considered and chosen for the design of the optical tape measure. Testing considerations and recommendations for the project continuation are also included. All of these sections are necessary for the project to be successful.

1 Design Objectives

The following list includes the team objectives for the design:

• The device shall operate with the simple push of a button.

• The device shall measure the distance from the back end of the device to an object point.

• The device shall be easy to aim in order to easily determine the object point.

• The device shall have an accuracy of ± 0.5%.

2 Functional Requirements

The following list includes the functional requirements specifications:

• The device shall measure distances up to 100 feet.

• The device shall have an accuracy of ± 0.5%.

• The recorded measurements shall be displayed on an LCD screen on the device.

• The device shall capture the distance from the device to any point within the measurable distance.

3 Design Constraints

The constraints list describes the restrictions on the end product design:

• The size of the tape measure shall be small enough to fit in the palm of the user’s hand.

• The dimensions shall be 6”x 8” x 3”.

• A couple of small batteries need to be able to supply enough power for the device to operate.

• The surface of the object being measured needs to reflect the incoming laser enough for the device to maintain its accuracy.

• The cost of all the components used in the prototype shall not exceed $355.

• The lasers used in the device must be of class 2 to ensure that they are not harmful to the eye under limited exposure.

• The device should be easier to use than a regular tape measure.

• The device needs to compensate for possible ambient light interference and any inclement weather conditions.

4 Technical Approach Considerations

The technology considerations list describes the available technologies which were considered for the implementation of the final design.

• Pulse-type time of flight systems. In this technology the laser emits very brief, very intense pulse of light. The instrument measures the amount of time the pulse takes to reach the target and return, then converts the time into a distance.

Advantages

▪ Several pulses can be averaged to increase accuracy.

▪ The device would be capable of being self-contained.

▪ Commercial optical tape measures use this method.

▪ Sufficient information is available to aid in design.

▪ The necessary parts for implementation are easier to locate.

▪ Farther distances can be measured.

Disadvantages

▪ An extremely fast timing device is required to time the travel time of a pulse.

▪ Ambient light interference can be problematic.

▪ The photo detector, the laser driver, and the laser diode are expensive.

• Modulated beam systems. The measurement is done by rapidly changing the strength of the laser to produce a signal. The time delay is calculated by comparing the output laser with the delayed signal returning form the target.

Advantages

▪ No need for an extremely fast timing device.

▪ The lack of fast devices would lessen the cost of some parts.

Disadvantages

▪ Laser must be modulated at a high frequency to obtain an accurate measurement.

▪ Not as accurate when measuring long distances.

▪ The team was unable to find an accurate enough phase detector.

▪ A feedback loop of the modulated signal would be required for comparison thus making an additional photo detector necessary.

• Laser beam’s intensity vs. visibility. The visibility of a laser beam at some distance away from the emitter is related to the intensity of the laser beam. The intensity of the laser can be varied until the laser is no longer visible on the object. Comparing this value with a set of known values the distance to the object can be derived.

Advantages

▪ A timing device would not be required.

▪ A phase comparison device would not be required.

▪ The overall design would be less complicated.

▪ The cost of the design would be lessened.

Disadvantages

▪ The desired accuracy would be difficult to obtain.

▪ Controlling the output laser power would be difficult.

▪ The team was unable to locate any parts that would make this design possible.

• Triangulation. Two or more lasers separated by a fixed distance would be aimed at the object point and the angles of the aimed lasers would be captured. Trigonometry would then be used to calculate the distance to the object point.

Advantages

▪ A timing device would not be required.

▪ A phase comparison device would not be required.

▪ No photo detector would be required.

▪ The overall design would be less complicated.

▪ The cost of the design would be lessened.

Disadvantages

▪ The use of multiple lasers would make a hand-held device impossible.

▪ The accuracy of the measurement would be lessened due to human error in aiming.

▪ An accurate angle would be difficult to measure.

▪ Setup of the device would be cumbersome.

▪ Multiple measurements would be difficult to obtain quickly.

5 Technical Approach Results

The final technical approach which was selected was the pulse-type time of flight system. This approach was chosen because of the high accuracy that can be obtained at large distances. This approach was also chosen because of the abundance of information that the team was able to collect on this technology due to the fact that this is the industry standard for range finding.

6 Testing Approach Considerations

The prototype shall be tested and debugged to make sure all parts of the system are being controlled properly. The laser device will initially be tested in low light environments. The device’s measurements shall be recorded and checked for accuracy at multiple distances from a known object. Later tests shall be done under abnormal environmental conditions. These tests shall check the device’s accuracy under several different weather conditions. Accuracy shall be recorded for each condition and checked against the accuracy of the ideal test.

The longevity of the device shall be checked by submitting the prototype to numerous trials. The prototype shall be judged a success if it is still functioning after 1000 trials.

The results of these tests shall be checked against the accuracy and distance constraints. If these constraints are met then the design shall be judged as a success. The team has created a test form in order to capture all aspects of each test. Appendix E: shows this testing form.

7 Recommendations Regarding Project Continuation or Modification

Currently, the team feels that it would be best to continue the project as it was originally intended to be carried with minor changes to certain design constraints. The first of the constraints to be changed is the computer modeling of a room. The team feels that the time required to design a software package and computer interface would constrict the time available for hardware design. The second constraint to be changed is the limiting of the implementation budget to $150. The team has found through more in depth research that parts such as photo detectors, laser drivers, and laser diodes cost more than what was originally thought. The team proposes that the implementation budget be increased to $355. This would adequately cover the expenses that are required.

2 Detailed Design

The following sections will outline the design of the optical tape measure in detail. All of the components that the team is currently looking at using in the design will be presented along with the details of their operation, operation cost, and possible sources of each component.

1 Design Overview

In order to design an accurate optical tape measure using the time of flight method, the team decided that there are four main modules needed. These modules are a timer, a laser transmitter, an optical receiver, and a microcontroller with a liquid crystal display (LCD). Figure 1 below shows a general block diagram which shows how the modules shall interact with each other.

[pic]

Figure 1: Time of Flight Block Diagram

The above block diagram of the optical tape measure operation procedure is further explained below in a step by step listing of the procedures.

Step 1: The user aims the device at the object to be measured.

Step 2: The user presses the activation button signaling the microcontroller to begin operation.

Step 3: The microcontroller sends a start signal to the timer and a trigger signal to the transmitter at the same time.

Step 4: The timer begins to count while the transmitter sends a laser pulse at the object to be measured.

Step 5: The laser pulse is reflected by the object to be measured and returns to the device.

Step 6: The receiver detects the returned laser pulse and sends a stop signal to the timer.

Step 7: The timer stops counting and sends the final measured time to the microcontroller.

Step 8: The microcontroller takes the measured time of flight and calculates the corresponding distance based on the speed of light.

Step 9: The microcontroller outputs the calculated distance to the LCD for the user to view.

2 Timer Module

A more detailed explanation of what makes up the timer module will now be discussed. This is the most essential component of the entire design in that it determines the ultimate accuracy that the device shall have. This accuracy is particularly difficult because of the fact that the device is required to time a light beam which is traveling at the extremely high speed of [pic] meters per second. At 100 feet the total round trip time of flight for a pulse traveling at the speed of light would only be

[pic].

In order to maintain an accuracy of ± 0.5% at 100 feet, the device needs to measure the distance to within half a foot or 0.1524 meters of the actual distance. This distance requires that the time resolution would have to be less than

[pic].

With this requirement in mind the team began searching for a semiconductor timing device. The results of this search produced the TDC-GP1. This device shown below in Figure 2 is a time to digital converter with a single channel resolution of 125 picoseconds and a double channel resolution of 250 picoseconds.

[pic]

Figure 2: TDC-GP1

This resolution would easily satisfy the error requirements outlined in the project plan. It would also cut down on the extra circuitry that would be needed because of the fact that the device outputs an eight bit digital signal. This makes the interfacing with the microcontroller a lot easier because the microcontroller requires a digital input. If the timer output had an analog signal, an analog to digital converter would have been needed to convert the timer output. With this device a direct interface is possible. A typical interface of the device with a microprocessor is shown below in Figure 3. The data terminals in the picture are the outputs from the timer containing the measured time of flight. For a more detailed explanation of all of the terminal pins please refer to Appendix A for the TDC-GP1 data sheet.

[pic]

Figure 3: Microprocessor TDC-GP1 Interface

The next constraint that the device needed to meet was the fact that the entire design needs to operate off of commercial batteries. The TDC-GP1 also meets this constraint in that a 2.7 volt to a 5 volt supply is needed to power the device. This voltage is low enough that a 9 volt battery would supply the necessary voltage.

The timer module is also what determines the minimum and maximum distances that can be measured. The memory registers in the TDC-GP1 can only store so much information before it runs out of space and a certain initial amount of time is needed before the first stop pulse can be read. Specifically, the TDC GP1 has a minimum time interval of 3 nanoseconds and a maximum time interval of 7.6 microseconds. The minimum time interval equates to

[pic] meters.

The maximum time interval equates to

[pic] meters.

Please note that the division of two is due to the fact that a light pulse will have to travel the distance from the object twice (there and back) during the measured time interval.

These metric units converted to feet are 1.476 feet and 3,740.16 feet respectively. This means that the minimum distance that the team’s design can measure shall be 1.5 feet and a maximum of 100 feet is, also, easily within the devices capabilities.

For a more detailed explanation of the TDC-GP1’s capabilities including multiple stop pins and ALU capabilities, please refer to the data sheet in Appendix A: .

3 Transmitter Module

The transmitter module includes a laser diode along with a laser driver to pulse the laser. In choosing the laser diode driver numerous guidelines had to be followed. The cost, performance, voltage specifications, and size were of the most eminent concerns. Models from an array of different companies were analyzed with the above mentioned parameters in mind.

The driver needed to be capable of generating a pulse that had a width in the nanosecond range and possess extremely sharp and fast rise and fall times. These rise and fall times need to be in the picoseconds range because of the undesirable time that would be added to the timers count from the delay in the rise of the pulse. This error, however, would be systematic and the team feels that it should be able to compensate for it in the microcontroller.

A second concern was voltage. The driver needed to be low voltage in order to enable the battery operation and small size of the tape measure. The voltage range needs to stay within a few volts up to about 10 volts.

These vague constraints proved to be very limiting and the IXLDO2SI was the one chip that best satisfied the initial constraints. A more detailed look of the chip is now given.

IXLDO2SI Features:

• Less than 1.5nsec minimum pulse width

• 600 ps rise and fall times

• 5.5V max supply voltage

• 10 mA max output current

The IXLDO2SI pictured below in Figure 4 can be purchased alone or with accompanying circuitry making the addition of the laser diode and the supply voltage the only necessary additions.

[pic]

Figure 4: IXLDO2SI Chip

The search for a laser that will be compatible with this driver is still under way. The laser that the driver company suggests and sells is not an affordable option. The group is looking for a similar laser from an alternative company that will possess the characteristics needed. The biggest obstacle to overcome is the speed of the pulse. The laser diode shall withstand very short bursts of energy from the laser diode driver. The laser diode will also need to emit light in the wavelength range of 700-900 nanometers, in order to match that of the design photodiode detector.

4 Receiver Module

The laser diode shall have a spectral wavelength of 700nm - 900nm. It travels a maximum of 100ft from the device to the object. The photo-detector will detect the laser’s short pulse signal in the range of the spectral response. The device receives the pulse signal and will immediately output a signal to stop the timer. The amplitude of the output signal is based on the received light intensity and wavelengths. The stop signal will not be sent until the detector receives a light intensity above its threshold.

To achieve the function of the photo-detector for the system, three photodiodes have been chosen based on the four constraints listed in Table 1. A discussion for each constraint has been provided in the paragraphs below. The final selection will be made based on these constraints.

Rise time/ Response time

Based on the nature of light, laser beams travel at an approximate rate of [pic]. The problem statement requires the device to measure distances up to 100 feet in length with a 0.5% tolerance. The device must achieve a minimum accuracy of 0.5 feet so the instrumental delay must not exceed

[pic]

if the triggering point is set to half of the rise time. Thus, the maximum rise time of the output signal needs to be less than

[pic].

If the rise time exceeds this limit, the delay in sending a stop signal to the timer may be too large to maintain the desired accuracy.

Also, a longer rise time will add undesirable counts to the TDC time due to the fact that the TDC will not turn off until the stop signal is sent by the photo detector. The team has determined that this error is systematic. This systematic error can then be compensated for in the microcontroller.

Spectral response range

The photodiode shall respond to light intensity and a range of light wavelengths. A narrow spectral response range should be chosen and it must contain the 850 nanometers wavelength of the laser signal. This narrow range can filter out the ambient light and as a result decrease the noise level.

Peak response wavelength

The peak response wavelength should be chosen close to 850 nanometers to correspond to the laser’s wavelength. This constraint enables the device to respond the best to the laser’s light rather than with the interfering light wavelengths.

Price

Due to the nature of this project, the team has set a goal to keep the photodiode price below $150. This goal was created to keep the total cost of the project to a minimum as the photodiode is the most expensive component.

Table 1: Photodiode Constraints

|Part |Rise Time |Spectral Response Range |Peak Response |Price |Supplier |

|Number | | |Wavelength | | |

|S8334 |1 ns |400nm-900nm |840nm |$90 |Hamamatsu Corporation USA |

|AD230-TO5 |0.55ns |320nm-1080nm |700nm |$64 |Pacific Sensor |

5 Microcontroller with LCD

The microcontroller is what makes each module function together in displaying a distance on the LCD. The tasks of the microcontroller start when the user initiates a measurement by pressing the button. The microcontroller then initiates the transmitter and starts the timer at the same time. The microcontroller then waits for the digital output from the TDC. Upon receiving the time in seconds from the TDC, the microcontroller converts the time to a distance in feet using this simple distance equation

[pic].

Before selecting a programmable microcontroller, the basic needs of the microcontroller needed to be determined. The team’s microcontroller needs input/output (I/O) pins to communicate with the other devices. One input pin from the measurement button will be needed to start the program. One output pin is needed to simultaneously start the timer and the transmitter. Eight input pins are needed to receive the digital time measurement from the TDC. The microcontroller will need 8-10 output pins to control the LCD. The microcontroller will need to have enough memory to store a program and a few measurements.

After knowing the basic needs of the microcontroller, the process of selecting a microcontroller began. Both Motorola and peripheral interface controller (PIC) microcontrollers were researched online. Both of these chips provided the needs of the optical tape measure. Interfacing with these chips include different programmers to burn the program onto the chip. The senior design lab provides a parallel port PIC Programmer to program the PICMicro. With the availability of this programmer, a PIC chip was the way to go.

There are several PICMicro chips available from . Most of these chips cost well under $10. The group decided on the PIC16F873A chip because of the availability of a header file for the PIC16F87 family. This particular chip includes 22 I/O pins. This amount should be enough to control the other modules in the optical tape measure design. The PIC16F873A cost is currently at $3.98. There is a vast amount of PIC information and code available online.

The program of the optical tape measure is being created with the accuracy of the distance measurement in mind. Several measurements are going to be taken when the user presses the button. These measurements are going to be averaged in the registers of the PICMicro before displaying the distance in feet on the LCD. Systematic error shall also be addressed in the program to adjust for timing issues in the rise and fall time of the devices. This constant adjustment shall be determined after several tests have been run. The team has developed pseudo code for the optical tape measure.

1. Program starts with user press of the button.

2. Initialize the register settings.

a. count = 0

b. sum = 0

3. While count < 1000

4. Start the timer and the transmitter

5. Add TDC output to sum

a. sum = sum + TDCout

6. Increase count

a. count = count + 1

7. End loop

8. Send [pic] to the LCD.

The PIC microcontroller is the brain of the optical tape measure. It ties all the modules together to create a working product. The program must work flawlessly and provide great accuracy. This is the final attempt at accuracy before providing the distance measurement to the user.

Resources and Schedules

The next section of this report will cover the resources and schedules of the project. Planning the schedule for the year, as well as, planning the resources that will be required is necessary for the team to be successful in its objectives. A comparison will be made from the original resources and schedules in the project plan and the revised resources and schedules based on the work performed thus far on the project to see how well the project was originally planned and to better prepare the group for future work.

1 Resource Requirements

These three sections contain information regarding the required resources for the project. There are three types of resources listed below; personnel requirements, other resource requirements, and financial requirements. Each section contains the original estimate and then an updated estimated based on the work done so far. A description is then added afterward to explain the differences between the two values.

1 Personnel Time Requirements

The following two tables list the original estimate of the time required by the team to complete the tasks necessary for the project in Table 2 and in Table 3 the actual amount of time which was needed or that will be needed based on the team’s progress thus far.

Table 2: Original Personnel Time Requirements

|Original Personnel Time Requirements |

|Name |Definition/ |Product Design |Prototype Implementing |Product Testing |Documentation |Total |

| |Research | | | | | |

|Jason Thompson |16 |34 |21 |21 |13 |105 |

|Bruce |23 |37 |17 |16 |10 |103 |

|Fu | | | | | | |

|Eugene Zimmer |19 |35 |18 |20 |10 |102 |

| |80 |141 |76 |75 |45 |417 |

|Totals | | | | | | |

Table 3: Revised Personnel Time Requirements

|Revised Personnel Time Requirements |

|Name |Definition/ |Product Design |Prototype Implementing |Product Testing |Documentation |Total |

| |Research | | | | | |

|Jason Thompson |22 |27 |21 |21 |13 |104 |

|Bruce |21 |29 |17 |16 |10 |93 |

|Fu | | | | | | |

|Eugene Zimmer |18 |26 |18 |20 |10 |92 |

| |84 |112 |76 |75 |45 |393 |

|Totals | | | | | | |

Comparing these two tables reveals that the team required a little bit more time defining and researching the problem and quite a bit less time designing the product than what was originally planned. These two differences are due to the fact that the team did a lot more research on what could be done and how to do it during the research and definition phase. This additional research made it easier for the team to decide upon the parts necessary for the design and where to find them than what was previously expected.

2 Other Resource Requirements

The following two tables list the originally predicted other resource requirements in Table 4 followed by the updated resource requirements based on the current status of the project in Table 5.

Table 4: Original Other Resource Requirements

|Original Other Resource Requirements |

|Item |Team Hours |Other Hours |Cost |

|Project Poster |10 |0 |$50.00 |

|Document Printing |10 |0 |Donated |

|Design Implementation |72 |Unavailable |$150.00 |

|Computer Software |30 |0 |Donated |

|Totals |122 |Unavailable |$200.00 |

Table 5: Revised Other Resource Requirements

|Revised Other Resource Requirements |

|Item |Team Hours |Other Hours |Cost |

|Poster printing |0 |3 |$40.00 |

|Laminating and cut |2 |2 |$21.00 |

|Foam board |1 |0 |$4.00 |

|Project plan binding |1 |1 |$4.00 |

|Document printing |5 |0 |Donated |

|Microcontroller |10 |0 |$20.00 |

|Pulsed laser diode |5 |0 |$60.00 |

|Laser driver |10 |0 |$70.00 |

|Time to digital converter (TDC) |3 |0 |$39.00 |

|Photo detector |20 |0 |$150.00 |

|Liquid crystal display (LCD) |5 |0 |$15.00 |

|Miscellaneous circuit components |5 |0 |Donated |

|Computer software |10 |0 |Donated |

|Totals |77 |6 |$423.00 |

Comparing these two tables reveals that the number of team hours expected to be taken up by the other resource requirements has gone down significantly while the estimated cost for the other resource requirements has gone up. The difference in hours is due to both the fact that the poster didn’t take as long as expected and because the amount of research that the team has done so far has enabled the team to spend less time trying to figure out how each component works. The cost has gone up because the team failed to realize the cost and specifications required in both the laser driver and the photo detector. A very fast rise time is required by both the laser driver and the photo detector to ensure that the laser pulse is a sharp edge and that the stop signal sent to the TDC is fast to maintain the desired accuracy. The overall cost of the poster went up around ten dollars because the team decided to laminate the poster in order for it to look more attractive. The team had not originally intended to do this.

3 Financial Requirements

The following two tables present the originally predicted financial resources in Table 6 and then the revised financial resources based on the current status of the project in Table 7.

Table 6: Original Financial Resources

|Original Financial Resources |

|Item |Without Labor |With Labor |

|Project Poster |$50.00 |$50.00 |

|Document Printing |Donated |Donated |

|Design Implementation |$150.00 |$150.00 |

|Labor at $10.50 per hour | | |

| Freese, Nick | |$1123.50 |

| Zimmer, Eugene | |$1071.00 |

| Thompson, Jason | |$1102.50 |

| Fu, Bruce | |$1081.50 |

|Subtotal | |$4378.50 |

|Total |$200.00 |$4578.50 |

Table 7: Revised Financial Resources

|Revised Financial Resources |

|Item |Without Labor |With Labor |

|Poster printing |$40.00 |$40.00 |

|Laminating and cut |$21.00 |$21.00 |

|Foam board |$4.00 |$4.00 |

|Project plan binding |$4.00 |$4.00 |

|Document printing |Donated |Donated |

|Microcontroller |$20.00 |$20.00 |

|Liquid crystal display |$15.00 |$15.00 |

|Pulsed laser diode |$60.00 |$60.00 |

|Laser driver |$70.00 |$70.00 |

|Time to digital converter |$39.00 |$39.00 |

|Photo detector |$150.00 |$150.00 |

|Misc. circuit components |Donated |Donated |

|Labor at $10.50 per hour | | |

| Freese, Nick | |$1092.00 |

| Zimmer, Eugene | |$966.00 |

| Thompson, Jason | |$1092.00 |

| Fu, Bruce | |$967.50 |

|Subtotal | |$4117.50 |

|Total |$408.00 |$4525.50 |

Comparing these two charts shows that the price without labor has gone up while the price including labor has gone down. The reasons for the price without labor going up were discussed in the previous section. The cost of the laser driver and the photo detector were unexpectedly high and the cost of lamination was added to the poster in order to improve its overall appearance. The price with labor went down due to the fact that the team expects to spend fewer hours on the project because of the detailed research that has been performed up to this point.

2 Schedules

Due to the complexity of the design process it is essential that the team outline its projected schedule well before the main bulk of the work is to be done. This way the group will have a complete understanding of everything that needs to be done and thus does not procrastinate and end up with an incomplete project.

1 Project Schedule

The schedule presented in Figure 5 contains both the original schedule from the project plan and then the actual schedule that was performed for the first semester. The blue bars are the originally planned scheduled tasks and the red bars underneath are the actual work done on each task so far. The second semester schedule is presented below the first in Figure 6. Please note that the second semester schedule is, as of right now, unchanged from the project plan so the team decided to omit the red revised schedule underneath the original tasks.

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Figure 5: First Semester Schedule

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Figure 6: Second Semester Schedule

Comparing the original schedule and the updated one show that the team is currently slightly ahead of schedule as far as the project definition, research, and designing are concerned. The updated schedule also shows that the team has been a little behind in the writing of this report and the creation of the poster. This delay is due to the fact that the team has run into outside obligations for other classes and hasn’t had time to begin these documents any earlier. The team has left the second semester schedule as it was originally planned. This is because the team feels that they will have everything prepared by the beginning of next semester to proceed as planned.

2 Deliverables Schedule

The team has to be aware of when the deliverables for the project are due. For this purpose a deliverable schedule was created. Figure 7 below shows the deliverables schedule as it was originally planned in the blue bars and then underneath each original task is a red bar representing the revised deliverable schedule. Please not that the second semester deliverables are as of right now will remain the same. For this reason the team has omitted the revised red bars underneath the second semester deliverables.

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Figure 7: Deliverables Schedule

Closure Materials

This section will summarize everything that was contained in this project plan along with all contact information for the faculty advisors and the team members.

1 Project Team Information

Listed below is the contact information that may be needed during the project. The first subsection contains the data for the project client, the second subsection contains the data for the two faculty advisors, and the third subsection contains the data for the student team members.

1 Client Information

The client for this project will be the Iowa State University Senior Design program. The two contacts listed below are the individuals in charge of this program.

Professor John W. Lamont

324 Town Engineering

Ames, IA 50011

Phone Number: (515) 294-3600

Fax Number: (515) 294-6760

Email Address: jwlamont@iastate.edu

Professor Ralph E. Patterson, III

326 Town Engineering

Ames, IA 50011

Phone Number: (515) 294-2428

Fax Number: (515) 294-6760

Email Address: repiii@iastate.edu

2 Faculty Advisors Information

Degang Chen

329 Durham

Ames, IA 50011

Phone Number: (515) 294-6277

Fax Number: (515) 294-8432

Email Address: djchen@iastate.edu

Aleksandar Dogandzic

3119 Coover

Ames, IA 50011

Phone Number: (515) 294-0500

Fax Number: (515) 294-8432

Email Address: ald@iastate.edu

3 Student Team Information

Jason Thompson

905 Dickinson #112

Ames, IA 50014

Phone Number: (515) 292-0195

Email Address: tommyt@iastate.edu

Eugene Zimmer

2300 Mortenson Parkway #14

Ames, IA 50010

Phone Number: (515) 460-5779

Email Address: zimmerec@iastate.edu

Bruce Fu

4529 Webster ST

Ames, IA 50014

Phone Number: (515) 441-0620

Email Address: largeyam@iastate.edu

Nick Freese

1007 Lincoln Way #6

Ames, IA 50010

Phone Number: (319) 929-1300

Email Address: nfreese@iastate.edu

2 Closing Summary

As the world advances and technologies become smaller and faster the old way of accomplishing simple tasks has become obsolete. Not that long ago everyone used the regular tape measure to which everyone is all accustomed. Now, however, there are several more options available to someone wanting to make a measurement. Ultrasonic devices have been created that have enabled a user to simply push a button to obtain a distance measurement to a desired object, but even these devices have their drawbacks. Ultrasonic tape measures are difficult to aim and are only accurate up to 50 feet. Thus this project will attempt to amend these difficulties by creating an optical device capable of measure distances up to 100 feet with the same type of accuracy that the ultrasonic devices have at 50 feet. The creation of an optical tape measure will also allow for the designation of the aiming point, thus making this measurement option a lot faster and a more reliable way of obtaining measurements.

References

Common optical sensing techniques for displacement sensors, Acuity Laser Measurement. 2003,

DEI/IXYS Integrated Circuits.

Electro-Optic Devices, Inc.

How a laser rangefinder works, Laser Technology Inc.

How lasers work, HowStuffWorks.inc,



Laseroptronix and our electro optical products and measuring systems. Laseroptronix

Merriam Webster Online.

Microchip.

Pacific Silicon Sensor Inc.

Pic Microcontroller Projects.

Senior Design Homepage.

Standard Classifications for Lasers, University of Kansas Academic Computing Services,

The Optical Tape Measure by American Visionwear. American Visionwear, LLC.

Transducers LLC Direct.

Appendices

A: TDC-GP1 Data Sheet

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B: G4176-01 Datasheet

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C: S8334 Datasheet

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D: AD230-T05

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E: Optical Tape Measure Testing Form

Optical Tape Measure Testing Form

Who:

Date and Time:

Where:

Testing purpose:

Reference angle: 0 15 30 45 60 75 90

Surface type:

Ambient light intensity:

|Trial # |Device Distance (ft) |Actual Measured Distance (ft) |% Error (actual-device)/actual |

|1 | | | |

|2 | | | |

|3 | | | |

|4 | | | |

|5 | | | |

|6 | | | |

|7 | | | |

|8 | | | |

|9 | | | |

|10 | | | |

Testing notes:

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Microcontroller

Timer

Transmitter

LCD

Receiver

Button

Start

Stop

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