IOWA STATE UNIVERSITY
Frozen Precipitation Detector
for SODAR Systems
Final Report
Ashor Chirackal, Imran Butt, Michelle Tan and Luke Lehman
12/6/2010
SDDEC10-06
Disclaimer
This document was developed as a requirement for Senior Design II at Iowa State University,
Ames, Iowa. This document is not a professional design. The information included in this
document aims to be accurate, but the team members, advisors, client, and Iowa State University
make no claims about the accuracy or the quality of this document. Users of this document must
ensure that no violations of any law regarding licensing and certifications occur. This document
is copyrighted by the team members and advisors who produced this document and no part of the
document may be reproduced without the permission of the course coordinator.
Table of Contents
Disclaimer ....................................................................................................................................... 2
Table of Contents ............................................................................................................................ 3
Executive Summary ........................................................................................................................ 8
Acknowledgment ............................................................................................................................ 9
Problem Statement ........................................................................................................................ 10
General Problem Statement .......................................................................................................... 10
General Solution Approach........................................................................................................... 10
Concept Diagrams ......................................................................................................................... 11
System Diagram ............................................................................................................................ 15
System Description ....................................................................................................................... 15
Operating Environment ................................................................................................................. 16
Non-technical Environment ...................................................................................................... 16
Technical Environment ............................................................................................................. 17
Intended Users and Uses ............................................................................................................... 17
Assumptions and Limitations ....................................................................................................... 17
Expected End Product and Other Deliverables ............................................................................. 18
Design Objectives ......................................................................................................................... 18
Functional Requirements .............................................................................................................. 19
Power Requirements ................................................................................................................. 19
Heater Control Requirements .................................................................................................... 19
Frozen Precipitation Detector (FPD)......................................................................................... 19
Non-functional Requirements ....................................................................................................... 19
Financial .................................................................................................................................... 19
Weather ..................................................................................................................................... 19
Constraints Considerations ........................................................................................................... 20
Power......................................................................................................................................... 20
Heater ........................................................................................................................................ 20
Acoustic Environment ............................................................................................................... 20
Technology Considerations .......................................................................................................... 20
Acoustics ................................................................................................................................... 20
Materials .................................................................................................................................... 20
Technical Approach Considerations ............................................................................................. 21
Piezoelectric sensor ................................................................................................................... 21
Design Approach .......................................................................................................................... 21
Research .................................................................................................................................... 21
Perform small scale tests: .......................................................................................................... 21
Partial Prototyping..................................................................................................................... 21
Complete Detailed Design ........................................................................................................ 22
Testing Approach Considerations ................................................................................................. 22
Safety Considerations ................................................................................................................ 22
Project Milestones and Evaluation Criteria .................................................................................. 23
Market and Literature Survey ....................................................................................................... 23
Possible Risks and Risk Management .......................................................................................... 24
Risks that will result in the failure of the product ..................................................................... 24
Risks that will disrupt the flow of the project management ...................................................... 24
Detailed Design ............................................................................................................................. 25
Input/ Output ............................................................................................................................. 26
User Interface ............................................................................................................................ 26
Hardware/ Software................................................................................................................... 27
Other Components..................................................................................................................... 27
Implementation.......................................................................................................................... 27
Testing Plan .................................................................................................................................. 27
Phase I ....................................................................................................................................... 27
Phase II ...................................................................................................................................... 27
Evaluation ..................................................................................................................................... 28
Design, calculations & schematics ............................................................................................... 28
TTL Comparators ...................................................................................................................... 28
Filters ......................................................................................................................................... 29
Amplifier Circuit ....................................................................................................................... 42
Peak Detector Circuit ................................................................................................................ 44
SODAR Test Results .................................................................................................................... 47
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Period and Amplitude Measurement ......................................................................................... 49
Frequency & Amplitude Measurements ................................................................................... 50
Signal after Amplification and Filtering (Clear) ....................................................................... 52
Signal after Amplification and Filtering (With Ice) .................................................................. 53
Future Work .................................................................................................................................. 56
Recommendations ......................................................................................................................... 57
Work Statement ............................................................................................................................ 57
Task Descriptions.......................................................................................................................... 59
EE 491: Senior Design 1 ............................................................................................................... 59
Defining and Planning .................................................................................................................. 60
Identify Need ............................................................................................................................. 60
Complete Project Definition...................................................................................................... 60
Define Requirements ................................................................................................................. 60
Perform Research ...................................................................................................................... 60
Map Project Schedule................................................................................................................ 60
Determine Budget ..................................................................................................................... 60
Documenting and Reporting ......................................................................................................... 60
Submit Weekly Status Reports .................................................................................................. 60
Develop Draft Website .............................................................................................................. 61
Update Project Website ............................................................................................................. 61
Write Draft Project Plan ............................................................................................................ 61
Write Final Project Plan ............................................................................................................ 61
Determine solution ........................................................................................................................ 61
Perform in depth study of piezoelectric plates .......................................................................... 61
Determine components .............................................................................................................. 61
Perform small case testing......................................................................................................... 61
Analyze based on results and make decision ............................................................................ 62
Test SODAR ................................................................................................................................. 62
Test the heating pad on the SODAR ......................................................................................... 62
Test the acoustic properties of the SODAR .............................................................................. 62
Basic parameters acquirement ................................................................................................... 62
Detailed Design ............................................................................................................................. 62
Create Preliminary Design ........................................................................................................ 63
Perform analysis ........................................................................................................................ 63
Determine final components ..................................................................................................... 63
Design Documents ........................................................................................................................ 63
Create Draft Design and Presentation ....................................................................................... 63
Present Design Review.............................................................................................................. 63
Write Draft Design Report ........................................................................................................ 63
Write Final Design Report ........................................................................................................ 63
EE492: Senior Design II ............................................................................................................... 64
Project Management ..................................................................................................................... 64
Weekly Status Reports .............................................................................................................. 64
Update Website ......................................................................................................................... 64
Design Poster............................................................................................................................. 64
Final Report .................................................................................................................................. 64
Final Report Draft ..................................................................................................................... 64
Final Presentation ...................................................................................................................... 64
Design ........................................................................................................................................... 65
Write user manual ..................................................................................................................... 65
Purchase components ................................................................................................................ 65
Fabricate Support Structure....................................................................................................... 65
Testing........................................................................................................................................... 65
Test and Debug Hardware ......................................................................................................... 65
Install Completed system .......................................................................................................... 65
Resources Requirements ............................................................................................................... 65
Time Resources ......................................................................................................................... 65
Cost Resources .......................................................................................................................... 66
Closing Summary.......................................................................................................................... 70
Lesson Learned ............................................................................................................................. 70
Contact Information ...................................................................................................................... 71
Client Contact Information........................................................................................................ 71
Faculty Advisor Contact Information ....................................................................................... 71
Team Contact Information ........................................................................................................ 71
Executive Summary
This document was written for the senior design team (SDDEC10-06) at Iowa State University to
record their work on building a better frozen precipitation detector for a SODAR unit.
This document primarily details the sensor that was chosen for the project and other circuits that
were designed in order to build the frozen precipitation detector. It also includes the testing
results and other recommendations for future reference.
SODAR units are used to measure wind shear in order to determine if a geographic area is a
viable location for a wind farm. The SODAR reflects sound waves off of a pad and into the
atmosphere. This pad needs to be clear of any frozen precipitation in order for the SODAR to
function effectively. A pre-installed heater is used to melt any frozen precipitation that may
accumulate on the pad. However, the current frozen precipitation detector does not allow for the
frozen precipitation to be melted proficiently. Therefore, there is a need for a frozen precipitation
detector that works efficiently.
Acknowledgment
The team would like to express their sincerest appreciation and gratitude to the following
contributors for their help and support throughout this project:
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Dr. Timothy Bigelow (Faculty Advisor) for his supervision and advice throughout the
project.
Mr. Doug Taylor (John Deere) for helping the team to understand the aims of the project
and also for his valuable feedback.
Mr. Josh Underwood (ASC) for providing substantial information on the equipment.
Dr. Manimaran Govindarasu (Senior Design I) for inspiring the team to develop a
presentable project.
Dr. Daji Qiao (Senior Design II) for providing guidance and feedback.
Mr. Leland Harker (ECpE Electronic Shop) for helping the team with parts and
components needed for the project.
Dr. Alan Czarnetzki (University of Northern Iowa) for providing time and equipment for
the team to test the design.
Problem Statement
The main purpose of this project is to optimize the number of times the heater should turn on in
order to reduce the system’s power consumption by designing a frozen precipitation detector that
is more efficient and accurate than the current model.
General Problem Statement
SODAR systems are used to measure wind shear up to 200 meters in the atmosphere. These
systems are usually located at remote areas for data collection. The SODAR system that we
designed for is the 4000WE model produced by Atmospheric Systems Corp. (ASC). This model
has a heater, a temperature sensor and a snow detector installed in it. The system is also designed
to be autonomous and is primarily powered by solar panels. The system also has a generator as a
secondary source and to provide power for heater operation.
The system operates by emitting sound waves from 4000Hz to 5000Hz through its 32 speakers.
These sound waves are emitted in short, 20 cycle, bursts that occur every two to three seconds.
These waves are then bounced off of an angled reflector pad that is located directly in front of
the speakers. The waves travel approximately 200 meters into the atmosphere and reflect back
into the SODAR. The purpose of the system is to measure and record wind shear data to be used
for meteorological purposes as well as wind farm planning.
In order to ensure the accuracy of the data collected, there is a need for a smooth and flat
reflector pad. If the pad is uneven or has any other obstructions, the data collection might be
distorted. In the winter, there is a chance for snow accumulation and it needs to be melted right
away in order for the data to be accurate. The system currently employs a precipitation detector
that produces many false positives resulting in excessive use of the generator and short fuel life.
General Solution Approach
The team’s approach is to use piezoelectric sensors to detect the presence of snow on the
reflector pad. These sensors will make use of the signals generated from the SODAR to tell the
difference when there is snow on the reflector pad or not. When snow is present on the sensor,
the voltage being produced will be less than the voltage when the reflector pad is clear. The
heater will only be turned on when the piezoelectric sensor has snow on it. The solution circuit
that incorporates amplifiers, peak detectors, filters and TTL logic comparators will be powered
by the SODAR.
Concept Diagrams
When the equipment is clear of snow/ice:
Reflected sound waves
Speakers
Reflector pad/Heater
Figure 1 Inside of the SODAR equipment without snow on the reflector pad.
When the equipment is has snow/ice on the reflector pad:
Reflected sound waves with distortion
Speakers
Layer of snow
Reflector pad/
Inefficient heater
Figure 2 Inside of the SODAR equipment with snow on the reflector pad.
The piezoelectric sensors enable us to determine if the reflector pad has snow or ice on it. Using
the sounds waves from the speakers, the sensors can detects the different voltage levels and turns
on the heater only when there is snow present. Since the sensors work continuously and detect
snow on the pad instead of as an attachment outside of the equipment, the sensors will signal for
the heater to turn on with fewer false positives. Also, because of the thinness of these sensors, it
will not obstruct the system’s operations.
Reflected sound waves with distortion
Speakers
Layer of snow
Reflector pad &
heater
Piezoelectric
Sensors
Figure 3 Inside of the SODAR equipment with snow on the reflector pad and piezoelectric sensors.
A more illustrative diagram of the piezoelectric sensors is shown below:
The figure above shows the piezoelectric sensors on the reflector pad. Each sensor will produce
individual voltage signals. If there is snow present on one of the piezoelectric sensor e.g. V1, the
voltage generated will be different from the one produced by sensors that are clear of snow e.g.
V2 and V3.
System Diagram
For implementation to the current system:
Power
Source
Temperature
Sensor
Heater
AND Gate
Piezoelectric
Sensors
Amplifiers
Filters
Sample &
Hold
Master
Control
OR Gates
System Description
Frozen Precipitation Detector
The entire system used to receive information, process, and produce a TTL signal to
control the heater.
Piezoelectric Sensors
These sensors are transducers that convert sound waves to electric voltages. Each sensor
will provide different output voltage based on the how much snow was covering the
surface of these sensors.
Design Circuit
In the design circuit are three main parts i.e. amplifiers, filters, and sample and hold.
Outputs from the piezoelectric sensors are very small and so appropriate amplifications
are needed for the signals to be properly analyzed. There will also be noise that surrounds
the equipment hence filters are built to only take in signals from 4 KHz to 5 KHz. Since
the speakers operates with burst signals, sample and hold circuit is added to maintain the
signal for a few seconds longer.
Logic Gates
If multiple piezoelectric sensors are used, a logic gate AND is necessary to determine
snow on different parts of the reflector pad. It could also take an input from the
temperature sensor to only have the heater on when the atmospheric temperature is low
i.e. winter. Also, logic ‘OR’gates can be used to combine 2 sets of sensors for
redundancy.
Heater
The heater is mounted under the reflector pad and is not detachable. This is the
component that the project needed to control by developing more effective sensors. It will
be used only during the winter and should only be turned on to melt the snow when there
is a certain level of snow accumulation.
Power Source
The equipment is powered primarily by the solar panels that are attached to it. This will
also be the power source for this design. It will provide power to the new circuit only as
the piezoelectric sensors will not require power to operate.
Temperature Sensor
The temperature sensor will measure the temperature and humidity in the atmosphere.
This is a preinstalled component in the equipment. The readings from this sensor may be
incorporated at a later date to improve robustness.
Operating Environment
Non-technical Environment
The plan is that the detector will be able to withstand hot, humid, windy, cloudy, rainy
and harsh winter weather. It will have to be able to function without any problems during
snow storms, freezing rain and blizzards. During summer months, it should still be able
to withstand the humidity and heat although the detector is not in use. The product will
most likely be situated at remote, deserted locations with high chances of rodents and
wild animals. The product will have to be able to stay in place on the reflector pad while
operating regardless of the harsh winter weather or being agitated by rodents or wild
animals. However, it should be able to be taken off for maintenance or replacement. The
product will have to endure hot temperatures (>100F) emitted from the heater if the
solution is to have the product placed directly on top of the reflector pad/heater. Also, it
will have to function well from very low atmospheric temperature (~-30F). The detector
will not be melted or burned by the heat from the heating pad and will not be frozen from
the harsh winter weather. It should be able to withstand the high wind speed if the
solution is to have the product placed as an attachment on the top of the equipment. Since
the detector is operating during winter, snow and ice will be the common operating
environment. Snow and ice will not interfere the operations if they are surrounding the
equipment and not on the equipment. Accumulation of snow and ice will interrupt the
SODAR operations thus it will turn on the heater.
Technical Environment
The current system works within an acoustic environment resulting from sound emitted
from the SODAR speakers. The passive sensor will not emit frequencies from 4000Hz to
5000Hz which would interfere with operation of the SODAR.
Intended Users and Uses
The primary intended user for this project is our client, Atmospheric Systems Corp. (ASC. The
design can be installed on older equipment where the current detector is facing problems or as a
replacement for the current detector. The product will be installed in purchased equipment
should ASC upgrade the systems for their clients. The product will be used to detect the presence
of snow and ice that is on the reflector pad. It will then send signals to the master controller to
turn on the heater effectively which in turn will melt the snow and ice on the reflector pad.
Assumptions and Limitations
All information about the SODAR system was provided to us by our contacts, Mr. Doug Taylor
and Mr. Josh Underwood. Information was also gathered from the ASC website. Although we
will still continue researching about the SODAR system, in order to further our solution, some
assumptions must be made.
Environment
The SODAR equipment will be used in areas with freezing conditions/ precipitation,
debris/ dust and wildlife.
Heater
The heater is not removable (glued-on) and cannot be altered. It will produce a constant
amount of heat. The temperature on the reflector is assumed to be high (>100F).
Temperature Sensor
The temperature sensor is functioning well and is able to detect the current temperature
accurately. Input from the temperature sensor can be used along with the logic gates we
intend to use.
Power Source
The Frozen Precipitation Detector (FPD) will have a constant source of power unless the
SODAR goes into hibernation mode.
Installation
The FPD is compatible with the SODAR systems. The FPD will be able to fit properly on
the reflector pad. A limited amount of space will be available on the heater to set up our
FPD.
Piezoelectric Sensor
The piezoelectric sensor will be able to handle the temperature changes from the heater
and the environment. The piezoelectric sensor must be able to send reliable signals.
Expected End Product and Other Deliverables
The final design of the product is the frozen precipitation detector with the proposed sensors and
the accompanying circuit. Should time and resources permit, logic gates and more sensors will
be added. A manual/report will be included should the manufacturer intend to use the design in
their products.
Design Objectives
The solution must be used to detect the snow and ice accumulation on the reflector pad. Our
objective is to use piezoelectric sensors placed on top of the reflector pad to detect the sound
emitted from the SODAR speakers. A customized circuit designed by the SODAR team will be
used to decide if the heater is necessary.
Since the solution is placed on the reflector pad, it needs be able to withstand the high heat from
the heater. It must be able to tell the difference between the surface that has precipitation
accumulation and the clear surface. The solution must not disrupt the SODAR operations.
Functional Requirements
Power Requirements
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The new detector must be primarily powered using the solar panels currently on the
equipment.
In order for the solution to be energy-efficient, the new detector must use the same
amount of power or less. The FPD cannot use more power than what the solar panels
generate.
In case of primary loss of power, the new detector must use the generator that was
already on the equipment. The generator has a finite amount of fuel. It cannot be
depended on to power the detector for a long period of time.
Heater Control Requirements
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The heater is to be controlled by the voltage that the FPD produces.
A large amount of frozen precipitation will affect the accuracy of the SODAR readings
and must be removed immediately. The heater needs to turn on when the voltage received
by the circuit is lower than a certain threshold.
Frozen Precipitation Detector (FPD)
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The FPD must be able to detect the snow or ice on the reflector pad.
The detector must not disturb with the operations of the SODAR
Non-functional Requirements
Financial
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The FPD should be economical and affordable.
In the case where the cost of the product exceeds the cost of the current detector, it should
provide more benefits than the current detector. Though it is more expensive, the product
will save on the fuel consumption expenses.
A budget will be determined as the project progresses. Ideally, the new solution should be
less than the cost of the current detector.
Weather
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Design must withstand weather conditions as explained in the operating environment
(Snow, extreme weather, unpredictable weather conditions like in Iowa or Kansas)
Design must also withstand the temperature of the heating pad.
Rain will not be an issue as long as it does not disrupt the operations of the SODAR
system.
Constraints Considerations
Power
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Power consumption must be lower than the current system.
There must be an increase in power efficiency to delay the hibernation mode of the
equipment.
If the system goes into hibernation mode, its operation will be stopped until fuel is
replenished.
The SODAR (without the heater) operates with 25 Watts primarily from the solar panels.
Heater
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Heating pad should be turned on when necessary. We have limited power available.
Primary power source is solar panels and secondary source is fuel tank (24 gal.).
Heater runs at a Power of 1800 Watts currently.
Heater cannot be changed or removed as it is permanently attached with the reflector pad.
Operates as one unit and cannot divide into parts
Acoustic Environment
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Design must not interfere with the SODAR system.
The SODAR uses a frequency between 4000Hz and 5000Hz.
Technology Considerations
Acoustics
The nature of our primary sensors depends upon the acoustic environment. We will need to
conduct studies on the properties of sound in order to make effective use of sound as a detection
tool.
Materials
Our primary sensors are piezoelectric sheets and their material properties need to be understood
and employed effectively for snow detection. The piezoelectric sensors must be securely placed
on the reflector pad. Lamination of the piezoelectric sensors will protect them from the
environment and a sturdy adhesive will attach them to the reflector pad.
Technical Approach Considerations
Piezoelectric sensor
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The piezoelectric sensor should have the material strength to with stand the temperature
extremes of the environment.
The response of the piezoelectric sensor must be clear enough to be analyzed by the
circuit.
Design Approach
In order to come up with an effective design by the end of the semester, we used the following
approach:
Research
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Problem definition and understanding the operation of the product
Determination of functional and non-functional requirements
Determine constraints and operating environment
Determine several viable solutions
o Read literature and research different sensors that could be used
o Design system block diagram and system descriptions
o Determine the components required for the sensors
o Perform literature survey to confirm our design approach and improve our
methods if needed
Perform small scale tests:
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Acquire components necessary to perform small level testing
Design a series component based tests to check performances
Perform simulation and required circuit and system analysis before building component
testing
Perform component based testing based on the design and analysis
Analyze the results of those components and make changes if necessary and retest if
required
Document analysis and results of each component
Have two solutions (primary and secondary) determined
Partial Prototyping
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If possible after performing component testing replicate the environment in which the
final product will be used and perform basic tests
Complete Detailed Design
To be implemented in fall 2010. Based on the small scale testing results we will complete the
design with the following specifications
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Input/output specification
Hardware and Software specification
Test Specification
Simulation modeling
Prototype and test design
Produce design documents
Testing Approach Considerations
Safety Considerations
Two important aspects regarding safety considerations for this project are the safety of the
product and the safety of the users.
Product safety is important because the damage on the product could put the SODAR operation
into an early hibernation mode that will result in the interruption of data collection. This will also
cause the heater to turn on when it is not needed resulting in increased power consumption and
fuel usage.
Some product safety issues that will be considered are:
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Electrical faults could occur since the product is connected with wires and this could
result in short circuitry, overheating.
The product could freeze due to hard weather conditions.
Shifting could occur if the product is not fixed properly on the reflector pad.
Damage could be caused by rodents that somehow got into the equipment trailer and this
could result in the possibility of damaged wires, malfunctioning sensors and broken
microprocessors/speakers.
Equipment could be flammable if overheating occurs.
User safety is also an important aspect since there will be some sort of human interaction with
the equipment.
Some of the user safety considerations are:
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Electrical shock could occur to users if any parts of the product are experiencing
electrical faults.
SODAR system is operating at a high sound intensity that could causes damage to the
human ears.
Abrasions could happen due to wires, tools and other objects.
Severe burn could occur if user is interacting with the equipment when the heater is
turned on.
Other safety considerations will involve the wildlife/rodent interactions and environmental
issues.
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Wildlife and rodents might be affected by the SODAR.
Rodents/birds might be burned if detected as obstacles on the sensors.
Project Milestones and Evaluation Criteria
Our team has set a numbers of milestones in this project. One of the important milestones that we
have determined is design and testing the prototype of our primary piezoelectric sensors. Next,
we would like to come up with the prototype of our secondary sensor which we would like
to implement as a back-up to our primary sensor. The team also considered testing
documentation as an important milestone as well. Other milestones can be found in our project’s
Gantt chart. Evaluation of the milestones is also an important task for the team. When
the testing and developing procedures are in progress, the team will determine the
evaluation criteria for the milestones.
Market and Literature Survey
The Frozen Precipitation Detection project is very unique to the client’s needs and specifications.
The piezoelectric sensors are used in other applications such as quality assurance, process
control, measurements of various processes etc. Their use in detecting snow is very unique and
we haven’t been able to find an application of piezoelectric sensors that are used in
detecting snow or ice. Some applications of piezoelectric films are outlined below.
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Detection and generation of sonar waves
Power monitoring in high power applications
Automotive engine management systems
Acoustic emission testing
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Inkjet printers
Possible Risks and Risk Management
There are certain risks associated with this project. We have identified these risks and also how
to manage our project in order to mitigate these risks.
Risks that will result in the failure of the product
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Components used are incompatible with the equipment and the environment as a result of
testing being done a laboratory.
o Components used will be analyzed thoroughly before we begin testing.
o Testing on the actual equipment will be performed.
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Complications might occur for mass-manufacturing of the product.
o Dimensions of the product must be accurate. It should match the dimensions of
the reflector pad.
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Ideas do not meet client’s wants.
o Ideas and steps leading to the design of the product will be discussed and
approved by the client before actual testing or implementing.
Risks that will disrupt the flow of the project management
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Components might be damaged during experimental period.
o Components must be handled with care at all time.
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Testing/Experiment results might be lost.
o Good and proper documentation skills must be executed.
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Team members do not have enough expertise in the software/programming area.
o Team members will have enough programming background to program the
product.
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We might experience the loss of a team member.
o Every task will be delegated to two members.
o Team members will still need to participate in Senior Design 2 through
video/phone conferencing even though they are away for internships/coops.
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The project might not be able to be tested under the right weather conditions.
o Team must begin testing/experimenting during winter.
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Team members (or anyone around us) might be injured during experiments/fabrication.
o All team members must be cautious at all time during these sessions.
o All protective gears like earplugs must be worn if necessary.
o Start experimenting at a low voltage level so that the sound generated will not be
harmful to the human ears.
o Testing will be done in a closed, soundproof room.
o Before the start of the sound experiment, a warning will be given to the people
that are in the same room so that they too will put on their protective
earplugs.
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Time constraint (missing deadlines, scheduling conflicts, delay while waiting on
materials)
o Detailed planning must be done in order to move forward in the project.
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Financial constraint (unknown budget at the beginning of the project)
o A cost analysis must be performed and will be reviewed during the
selection of the best option.
o Work with the current allocated budget that is given by the department before
using for the subsidized fund.
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Having difficulties in locating potential components for testing/experimenting.
o Design must use easily found components since the product will be used
implemented for many SODAR systems.
Detailed Design
The input for the FPD will be the sound that the SODAR unit producesThe piezoelectric sensor
on the reflector pad will detect the sound wave and generate a response voltage. This voltage
will depend on whether frozen precipitation exists on the reflector pad. If frozen precipitation is
on the reflector pad, the voltage will be lower than if the reflector pad was clear.
This signal is sent through our circuit. First the voltage is amplified from the millivolt to the volt
range. Second, the band-pass filter is used to only let the signal between 4 and 5 kHz through.
Third, the peak detector holds the maximum voltage of the signal. Lastly, the signal is converted
to TTL on/off signal by a comparator circuit.
Input/ Output
The voltage generated by the
piezoelectric transducer
(covered with snow)
+
V1
+
V2
+
V3
The voltages generated by
the piezoelectric
transducer (clear of snow)
In this diagram, the arrows are the sound emitted by the SODAR speakers, and the ovals are the
piezoelectric sensors receiving the sound. The small circles covering the first oval represent
snow. Each of the sensors has a corresponding voltage (V1, V2, V3). With a clear surface, the
voltages will give a certain voltage. If the surface is covered as in V1, the voltage will be lower.
With a low voltage, the heater would be turned on.
User Interface
The SODAR is meant to be autonomous. Therefore, user interface should be kept to a minimum.
Installation will be required from the user. The FPD needs to be attached to the SODAR and
powered by the SODAR. A 12 pin input will connect the FPD to the heater.
Hardware/ Software
No software is necessary for the FPD. A customized circuit, designed by the SODAR team, will
be used to turn the heater on or off.
Other Components
The circuit will use these components
1)
2)
3)
4)
5)
1.5k, 6.8k 1k, and .1k resistors
1000uF, 30pF, and .01uF capacitors
1k-10k potentiometer
LM741/356 Operation Amplifier
Diode
Implementation
Implementation of the FPD involves permanent attachment of the circuitry and piezo-electrics to
SODAR systems. These SODAR systems must be operated in environments that produce frozen
precipitation and must have a heating unit installed. No such unit was available to implement our
design on in the time frame allotted. As such, a prototype unit was implemented on a SODAR
system lacking the heating hardware. The output of the prototype FPD was routed to an LED
indicator to simulate heater operation. The prototype FPD was not permanently installed on the
SODAR system but was implemented in a similar fashion to the intended installation of a
permanent FPD.
Testing Plan
The testing of the FPD was planned in two major phases. The first phase consisted of testing the
individual pieces of the FPD circuitry. The second phase consisted of prototype testing on a
SODAR system.
Phase I
The major parts of the FPD are as follows: Amplifier, Band-Pass Filters, Sample and Hold
circuitry. Construction and testing of these parts was conducted simultaneously in order to
produce a rapid prototype. Simulation of a SODAR signal was produced at a lower level in
laboratory in order to test functionality of each of these subsystems. Signal pulses were
generated using a signal generator and results were measured with oscilloscopes and digital
multi-meters. After these subsystems were finalized, a prototype system was constructed.
Phase II
Integration with the SODAR system is a crucial part of the implementation of the FPD. Each
FPD must be tuned to the amplitude and frequency of the SODAR system that it will be
implemented on. The prototype we built was initially designed for a system producing impulses
in the 4 kHz range. The SODAR system that we implemented our prototype on produced
impulses in the 4.5 kHz range. The SODAR system is located at the University of Northern Iowa
and our team made two trips to Cedar Falls, Iowa to evaluate and test our prototype FPD. Testing
on the SODAR included tuning of the FPD to match the SODAR specifications. Testing on the
SODAR included clear signals and frozen precipitation signals. Successful prototype operation
was achieved during both visits.
Evaluation
The original client for the FPD project, John Deere Renewables, was unable to participate in the
senior design project for the Fall 2010 semester. As a result of this complication we contacted
the parent company producing the SODAR systems. Mr. Josh Underwood of Atmospheric
Systems Corporation in Santa Clarita, California was our primary contact throughout the fall
2010 semester. Correspondence with Mr. Underwood included design criteria, SODAR
specifications and informal evaluation of the FPD. Primary evaluation was conducted by the
team at Iowa State laboratories in the Electrical Engineering department and at the Cedar Falls
test site. Evaluation included testing of the individual subsystems using simulated inputs as well
as testing using real-world inputs from the SODAR system. Evaluation was based on original
design criteria provided by John Deere Renewables and was modified according to new client
interaction and availability of necessary equipment. Primary goals included fabrication of a
working prototype, implementation of a working prototype on a SODAR system and fulfillment
of design criteria such as cost, energy consumption, ease of fabrication, durability etc.
Design, calculations & schematics
TTL Comparators
A comparator was implemented at the end of the circuit in order to produce a digital signal that
would turn the heater on or off. A 12V signal represents an on signal and a OV signal represents
an off. The comparator circuit accepts a 0-3V signal from the output of the Peak Detector and
turns the heater on when an approximately 20% reduction in signal is received from the
piezoelectric sensor.
Filters
The team designed and implemented Butterworth filters to remove the noise signal from the
output of the piezoelectric films.
High Pass Filter
Below is the frequency response of the High pass filter in Matlab
The cutoff frequency was chosen as fc = 2000 Hz
Code and Calculations
s = tf('s')
fc = 2000; %cutoff frequency
wc = 2*pi*fc %cutoff frequencys (radians)
K=2 %Order of transfer function
Hhp= (s^2)/ ( s^2 + sqrt(2)* wc* s + wc^2)
Transfer Function
Frequency Response:
Basic Design
Component Calculation
High Pass Filter Schematic
Low Pass Filter
Code and Calculations
s = tf('s')
fc = 8000; %cutoff frequency
wc = 2*pi*fc %cutoff frequencys (radians)
K=2 %Order of transfer function
Hlp2= wc^2/( s^2 + sqrt(2)*wc*s +wc^2)
Transfer Function based on our requirements
Frequency Response of the Low Pass filter
Basic Design
Component Calculation
Low Pass Filter
Band Pass Filter
Code and Calculations
Band pass filter is obtained by simply multiplying the transfer functions of High pass and Low
pass filter.
Hbp = Hlp * Hhp
Transfer Function of Band Pass
Frequency Response of Bandpass Filter
Band Pass Filter
Combining the Low Pass and High Pass together, the schematic of the Band pass filter is given
below.
Filter Simulation on P-Spice
Below is the result of the simulation run on P-Spice for the band pass filter.
Frequency Response of the band pass filter
Below are the results from the filter actually implemented
Frequecy Response of Filter Circuit
1.4
1.2
Vo/Vin
1
0.8
0.6
Vout/Vin
0.4
0.2
0
Frequency (Hz)
Amplifier Circuit
The team used 741 op amps to amplify the voltage generated by the piezoelectric due to sound.
Design
Using Inverting configuration
Rf=tunable potentiometer (104)
Rin=1.1KOhm
Testing the amplifier
Using a high gain amplifier we got the following results
With a Vinput of 100mVpp and after filtering
Peak Detector Circuit
The peak detector in Figure 1 is similar in many respects to the sample-and-hold circuit. A diode
is used in place of the sampling switch. Connected as shown, it will conduct whenever the input
is greater than the output, so the output will be equal to the peak value of the input voltage. In
this case, a LM741 is used instead of the LM 101/102 as a buffer for the storage capacitor, giving
low drift along with a low output resistance.
Design
Positive Peak Detector with Buffered Output
http://www.freecircuits.net/circuit-42.html
As with the sample and hold, the differential input voltage range of the LM101 permits
differences between the input and output voltages when the circuit is holding.
Test Results
The team tested the Peak Detector for different frequencies. The peak detector tracks the
amplitude or the peak value of an AC signal with in an accuracy of 9 to 13%
Frequency
Input Max from
Filter
Peak Detector
Voltage
Difference
% loss
500
0.11
0.1
0.01
9%
1500
0.56
0.48
0.08
14%
2000
0.94
0.84
0.1
11%
2500
1.18
1.04
0.14
12%
3000
1.24
1.12
0.12
10%
3500
1.28
1.05
0.23
18%
4000
1.22
1.08
0.14
11%
4500
1.18
1.06
0.12
10%
5000
1.2
1.05
0.15
13%
5500
1.16
1.03
0.13
11%
6000
1.14
1.09
0.05
4%
6500
1.12
0.97
0.15
13%
7000
1.12
0.98
0.14
13%
For 4.5Khz, which is the frequency used by SODAR, the performance of the peak detector at
different amplitudes of input is given below
Vin
Volt at Peak Detector
Difference
% loss
0.25
0.18
0.07
28%
0.5
0.41
0.09
18%
0.75
0.64
0.11
15%
1
0.877
0.123
12%
1.25
1.105
0.145
12%
1.5
1.331
0.169
11%
1.75
1.553
0.197
11%
2
1.771
0.229
11%
2.25
1.984
0.266
12%
2.5
2.3
0.2
8%
2.75
2.54
0.21
8%
3
2.78
0.22
7%
3.25
3.01
0.24
7%
3.5
3.24
0.26
7%
3.75
3.48
0.27
7%
4
3.71
0.29
7%
4.25
3.9
0.35
8%
4.5
4.17
0.33
7%
4.75
4.405
0.345
7%
5
4.6326
0.3674
7%
SODAR Test Results
SODAR Speakers 1
Piezo Installation 1
Piezo Installation 2
Frozen Precipitation Detector 1
Frozen Precipitation Detector 2
Period
andPiezo
Amplitude
Measurement
Signal from
1
Frequency & Amplitude Measurements
The team calculated the frequency and amplitude of the signal received by the piezoelectric by
using the oscilloscope.
Frequency: 4.402 KHz
Pk-Pk Voltage Range: 30-160mV
Different Phase voltages
The team found three types of voltages received by the piezoelectric. The difference in voltages
is due to the phases of the sound generated by the SODAR speakers. These voltages with
associated waveforms are given below.
Phase I
Pk-Pk (Delta) = 148mV
Phase II
Delta (pk-pk) Voltage = 104mV
Phase III
Very low voltage from the third phase sound
Delta (pk-pk) Voltage 38mV
Signal after Amplification and Filtering (Clear)
After ensuring that the piezoelectric was detecting the sound generated by the speakers, the team
tested the piezoelectric signal after passing it through required amplification and filtering. The
voltages measured and waveforms are given below:
Pk-Pk Voltage 1: 3.62 V
Pk-Pk Voltage 2: 2.30 V
Pk-Pk Voltage 3: 0.563 V
Delta (pk-pk) Voltage:2.3V
Signal after Amplification and Filtering (With Ice)
After checking the validity of amplification and filters the team tested if the piezoelectric can
produce a lower voltage signal after covering it with snow. The picture below shows the
piezoelectric covered with crushed ice.
Waveforms:
After covering the piezoelectric with crushed ice the sensor was only able to detect the two
largest sound signals. The oscilloscope wasn’t able to capture the smallest signal which is
Voltage 3.
Voltage 1 (largest)
Voltage 2 (2nd Largest)
Attenuation Calculation:
Following is the loss in signal strength due to snow accumulation for the sensor
Voltage Signal
(Phase)
Clear
(V)
Covered
(V)
Loss (V)
% Loss
1
3.62
0.82
-2.8
-77%
2
2.3
0.46
-1.84
-80%
3
0.536
0.02
-0.516
-96%
The value for Voltage 3 in case of covered is an assumed value. Since the oscilloscope cannot
detect a signal less than 10mV, we assume it is around the magnitude of 1-5mV. In this case the
attenuation is greater than 95%.
Output at the Peak Detector
Below is the output at the peak detector based on the clear voltages seen by the peak detector
after filtering
Vin (clear)
Peak Detector
Difference
% loss
Phase1
3.62
3.36
0.26
0.071823
Phase2
2.6
2.123
0.477
0.183462
Phase3
0.534
0.475
0.059
0.110487
Vin (covered)
Peak Detector
Difference
% loss
Phase1
0.82
0.72
0.1
0.121951
Phase2
0.46
0.3825
0.0775
0.168478
Phase3
X
X
X
X
In case of covered with snow
Difference in DC value of the peak detector
Peak Detector(
clear)
Peak Detector
(covered)
Difference
% loss
3.36
0.72
-2.64
79%
2.123
0.3825
-1.7405
82%
0.475
X
X
X
As we can see that covering the piezoelectric with a moderate amount of crushed ice has resulted
in a drop of approximately 80% of the voltage values at the peak detector and also at the filter
output.
Future Work
Just as the SODAR system has multiple applications, so does the frozen precipitation detector.
Our prototype system is ready to be adapted to the needs of the next client. The current revision
of the FPD is prototyped on a breadboard using readily available and inexpensive through-mount
components. This prototype should be constructed on PCB board for durability and sealed
against the elements. PCB layout and construction are advised as future work because the final
requirements of our design are not fully specified. For use on SODAR systems the FPD circuitry
and piezo-electrics will need to be protected against elements such as heat, cold, wind and
moisture. The piezo-electrics will need to be covered in a thin laminate material that will not
significantly impede their function but will protect them from moisture. The FPD circuitry will
need to be encased in a structure that will shield the components from moisture as well as direct
sunlight in order to reduce maximum temperature. Integration with the SODAR system heating
circuit is still partially incomplete due to lack of data on or access to a SODAR system equipped
with heating elements and associated circuitry. Output from the FPD is a high/off low/on signal
that is easily tunable to the required on/off data requirements of the system it is integrating with.
This output needs to be matched to the system it will be interfacing with and the appropriate
connector will need to be added to the system.
Recommendations
In addition to the future work required for successful implementation of our design there are a
few recommendations. Interfacing with existing precipitation detecting elements on the SODAR
system is recommended to improve reliability and robustness of our design. Additional piezoelectric sensors at different locations on the reflector board will further improve coverage and
reduce failure. Lastly, multiple adjacent piezo-electrics are recommended to be tied to the same
FPD circuit with the addition of simple logic to account for single or multiple failure of a piezoelectric.
Work Statement
Duration
(Days)
EE 491
Start Date
Finish Date
1/19/2010
5/7/2010
Defining and Planning
40
1/19/2010
2/28/2010
Identify Need
6
1/19/2010
1/25/2010
Complete Project Definition
4
1/25/2010
1/29/2010
Define Requirements
7
1/29/2010
2/5/2010
Perform Research
91
2/5/2010
5/7/2010
Map Project Schedule
20
2/15/2010
2/25/2010
Determine Budget
9
2/19/2010
2/28/2010
Documenting and Reporting
106
1/19/2010
5/7/2010
Submit Weekly Status Reports
102
1/19/2010
5/1/2010
Develop Draft Website
2
2/21/2010
2/23/2010
Update Project Website
104
2/21/2010
5/7/2010
Write Draft Project Plan
9
2/19/2010
2/28/2010
Write Final Project Plan
3
2/28/2010
3/3/2010
Determine viable solutions
30
3/1/2010
3/31/2010
Primary: Piezoelectric electric sensor
Perform in depth study of Piezoelectric plates
7
3/1/2010
3/8/2010
Determine system description
7
3/5/2010
3/12/2010
Determine components
3
3/12/2010
3/15/2010
Perform small case testing
6
3/16/2010
3/22/2010
Analyze based on results and make decision
2
3/22/2010
3/24/2010
Test SODAR
10
3/22/2010
3/31/2010
Test the heating pad on the SODAR
2
3/26/2010
3/28/2010
Determine the Environment Parameters
2
3/26/2010
3/28/2010
Test the Acoustic Properties of the SODAR
2
3/26/2010
3/28/2010
Basic Testing using Piezoelectric Sensors
2
3/26/2010
3/28/2010
Detailed Design
19
4/1/2010
4/20/2010
Create Preliminary Design
6
4/1/2010
4/7/2010
Perform Analysis
4
4/7/2010
4/11/2010
Determine Final Components
1
4/10/2010
4/11/2010
Draw Schematics
9
4/11/2010
4/20/2010
Design Documents
25
4/1/2010
4/26/2010
Create Draft Design and Presentation
7
4/13/2010
4/20/2010
Present Design Review
6
4/21/2010
4/27/2010
Write Draft Design Report
21
4/2/2010
4/23/2010
Write Final Design Report
4
4/22/2010
4/26/2010
EE 492
116
8/23/2010
12/18/2010
Based on the solutions determined begin designing
Documenting and Reporting
109
8/31/2010
12/17/2010
Submit Weekly Status Reports
102
8/31/2010
12/11/2010
Update Project Website
102
8/23/2010
12/11/2010
Design Project Poster
44
11/28/2010
12/6/2010
Write Draft Final Report
31
10/28/2010
11/28/2010
Write Final Report
7
12/10/2010
12/17/2009
Prepare Final Presentation
7
12/10/2010
12/17/2010
Documenting
92
8/23/2010
12/1/2010
Write User Manual
92
8/23/2010
12/1/2010
Build system
37
8/23/2010
12/6/2010
Purchase Components
7
8/23/2010
12/17/2010
Put together the Frozen Precipitation Detector
37
8/23/2010
9/30/2010
Testing
90
8/24/2010
11/22/2010
Test and Debug Hardware
47
9/30/2010
12/1/2010
Install Completed System
7
11/15/2010
11/22/2010
Test on SODAR
7
11/22/2010
12/1/2010
Task Descriptions
EE 491: Senior Design 1
The team will make sure that all deadlines are met and all deliverables are received at the end of
the project. This shall be done by managing the project effectively with proper definition,
preparation, design and fabrication.
Defining and Planning
The team will develop a project plan which serves as a binding agreement between the team and
the client. The document shall ensure all requirements are completely understood by team
members and client and the expectations and deadlines of the project are met. The team will
discuss necessary tasks to complete the project along with their respective priorities.
Identify Need
The team shall work with the client and advisors to determine the needs to be met by the project.
Complete Project Definition
To define boundaries for the project proposal, the team shall meet with advisors and as a group
to determine the requirements that will best meet the demands of the client.
Define Requirements
The team shall work with the client to decide the requirements that will be met by the end. The
requirements shall be organized into functional and non-functional requirements, and
differentiation will be made between what will be done and extra goals.
Perform Research
The team will research existing technologies and how they can be used for snow
detection.
Map Project Schedule
The team shall map out a project schedule to make sure that all deadlines are met and all tasks
are accomplished in a reasonable amount of time. The project schedule shall make sure that all
members of the team are involved in all aspects of the project.
Determine Budget
The team shall devise a budget which will reflect the financial needs of the project. The budget
shall be fluid allowing for changes in design based on the client’s desires.
Documenting and Reporting
Submit Weekly Status Reports
The team shall document all steps in the design process through weekly reports, a website and a
poster which shall display relevant information. A final project document will describe final
project results.
Develop Draft Website
The team shall develop a website dedicated to the project. The website shall contain the
project description and solution approach along with all the documentation associated with
the project, as well as information on the team members.
Update Project Website
Throughout the course of EE491/EE492 the website with the current version of their
documentation and any other information desired will be updated regularly.
Write Draft Project Plan
A plan will be drafted which lays out the course to be followed in the design phase of the project.
Write Final Project Plan
The plan is to be approved by the advisor, client and program coordinator, as well as each
member of the team. This plan is to serve as a binding agreement between the team and the
client.
Determine solution
Perform in depth study of piezoelectric plates
The team shall work with the advisor in performing an in depth study on the use of
piezoelectric sensors and their properties. This will involve reading manuals, articles, patents
etc. The purpose is to give a better understanding of the properties of acoustics and their use to
snow detection
Determine components
The team shall determine the components necessary to implement the solution.
Perform small case testing
The team shall acquire sample components to run basic level testing. The results will be well
documented and shared with the advisor and client.
Analyze based on results and make decision
The team shall analyze the results of the basic experiments and decide on the
effectiveness of the primary solution
Test SODAR
Test the heating pad on the SODAR
The team shall perform tests on the heating pad of the SODAR to determine its
characteristics such as
o Time taken to melt a certain amount of snow
o Behavior of the piezoelectric plates on the heater
Test the acoustic properties of the SODAR
The team shall also determine the effect of the acoustic environment on the piezoelectric
plates.
Basic parameters acquirement
The team shall note the basic parameters such as space available, heating surface properties,
location of power source etc. This will help the team in determining the installation constraints
for the FPD
Detailed Design
The team shall follow all steps to create the design report. Work shall be approximately divided
among all team members.
Create Preliminary Design
Based on the solutions determined the team shall work with the advisors and shall develop an
initial design which takes all functional requirements and non-functional requirements into
consideration. The results from the solutions development will also be used
Perform analysis
The team shall simulate their design to assure that it works, and shall make sure that all part
specifications are appropriate before ordering them.
Determine final components
Appropriate components shall be selected for the project, keeping future system expansion in
mind.
Design Documents
Create Draft Design and Presentation
The team shall prepare to answer any questions the design review board has, to prove the
feasibility of their design.
Present Design Review
The team shall present the design to the Design Review Board, and shall show the feasibility of
the project, the effectiveness of the design, and why certain design elements were chosen.
Write Draft Design Report
The team will draft a document recording the technical design specifications of the project. The
document shall include mathematical reasons why certain points were included and include
technical drawings of the system.
Write Final Design Report
The final design shall be approved by the design board, advisors and clients before proceeding.
EE492: Senior Design II
Project Management
The team shall make sure that all deadlines are met and all deliverables are received at the end of
the project by managing the project effectively with proper definition, preparation, design and
fabrication.
Weekly Status Reports
The team shall maintain contact with advisors and the course coordinator and update them
on current project status. The team shall document project work each week, and report weekly
via email on current status and plans for the upcoming week. The time spent by each member
shall be recorded and a semester tally shall be kept of all hours spent on the project by the team
members.
Update Website
Throughout the course of EE492 the team shall update the website with the current
version of their documentation and any other information required.
Design Poster
The team shall create a poster for the project, highlighting the solution the team has developed.
The team shall meet all poster guidelines laid out by the instructor. Using those guidelines, the
team shall produce a poster that satisfies the course and client requirements.
Final Report
Final Report Draft
The team shall develop a final report document for the final results of the project. The
team shall meet with advisors and as a group, to discuss and evaluate the success of the project
with respect to the requirements. The final report shall discuss the success or failure of the
project. Work shall be divided among team members approximately equally.
Final Presentation
The team shall report on the final results of their project, providing information on testing and
final installation of the prototype. The team shall be evaluated to see if they met all goals and
requirements.
Design
Write user manual
The team shall develop a user manual to accompany the completed prototype so that following
groups or student may use it and not cause harm to themselves of the grid.
Purchase components
After testing, components will be changed as needed, and the final components for building the
prototype unit will be purchased.
Fabricate Support Structure
The support mechanism for the solar array shall be built and tested, to be sure that it meets safety
and other requirements, and then installed.
Testing
Before delivery, the team shall build and thoroughly test a prototype of the hardware, while
carefully documenting outcomes or failures. Expected and actual results will be compared.
Test and Debug Hardware
The hardware shall be thoroughly tested to make sure that it meets all safety and technical
requirements.
Install Completed system
The team shall develop a working prototype to be used for testing and final implementation.
Resources Requirements
Time Resources
The following is cost estimates for student labor. In the nature of senior design, students are
working on the project for free but this could be used as a reference. Typically, the labor cost of
a part-time student is approximately $20/hour.
Labor
Cost/Hour ($)
Labor
Cost/Member($)
Ashor Chirackal
Imran Butt
Time
Commitment
(Hours)
350
350
20
20
7000
7000
Michelle Tan
350
20
7000
Luke Lehman
180
20
3600
Members
Total Labor Cost
$ 24,600
Cost Resources
The following is the updated cost estimates of the tools and components needed to test, build and
develop the product.
i.
Frozen Precipitation Detector
Materials
1. Amplifiers
2. Piezoelectric Sensors
3. Resistors, Capacitors,
Potentiometers, Diodes, LEDs and
Logic Gates
4. PCB
5. Software to design the PCB
6. Wiring, Conduits and Connectors
7. Other misc. components and tools
Total Material Cost
ii.
Cost Estimates ($)
30
200
40
20
--10
10
310
Working Prototype
Materials
1. Piezoelectric Sensors
2. Breadboards
Cost Estimates ($)
50
20
3. Resistors, Capacitors,
Potentiometers, Diodes, LEDs and
Logic Gates
4. Amplifiers
5. Testing Cost (Transportation, etc)
6. Other misc. components and tools
Total Material Cost
40
30
50
10
150
Closing Summary
SODARs are one of the most used equipment for wind profiling. They are usually deployed at
remote location to assess if the location is suitable for a wind farm. Currently, our client, ASC,
manufactures this equipment to sell to different buyers.
However, the equipment needs some improvements in order for the system to work more
efficiently. Our team is developing a solution that will make the system work for a longer period
of time before it goes into hibernation mode. In order for us to achieve that, we have to develop a
new, more efficient, method of detecting frozen precipitation.
This solution has been tested and it is feasible to be implemented on the SODAR
equipment. We hope that our contribution in this project will help development in the wind
industry.
Lesson Learned
This project definitely had some hassles. A major one was switching from John Deere to ASC
and another one was finding a SODAR in Iowa to work on. However, we transitioned smoothly
from John Deere to ASC and a SODAR was available to us at Cedar Falls. We learned how to
overcome any conflicts that arose.
This project taught us more about circuit design and piezoelectric technology. The circuit used in
this project was of our own design specifically made to handle the input from the piezoelectric
sensors. Before this project, we were unfamiliar with piezoelectric technology. Now, we
understand the purpose behind piezoelectric sensors.
Contact Information
Client Contact Information
Team Contact Information
Josh Underwood
Ashor Chirackal
Marketing and Business Development
Phone: 563-650-8711
Atmospheric Systems Corporation
Email: ashorc@iastate.edu
Office: (661)294-9621
Cell: (949)351-9516
Imran Butt
Fax: (661)294-9667
Phone: 515-664-7972
Email: josh@minisodar.com
Email: imranb@iastate.edu
26017 Huntington Ln., Unit F
Valencia, CA 91355
Michelle Tan
Phone: 515-708-2478
Faculty Advisor Contact
Information
Email: elle87@iastate.edu
Prof. Timothy Bigelow
Luke Lehman
Assistant Professor
Phone: 515-451-5014
Iowa State University
Email: lehmanl@iastate.edu
2113 Coover Hall Ames IA 50011
Phone: 515-294-4177
Email: bigelow@iastate.edu