Master Portfolio

Wayne Holt
Mechanical & Analysis Engineer
Metro Atlanta | (770) 862-7331 | bwayneholt@gmail.com | www.linkedin.com/in/bwayneholt
Contents
 Small Machine Design
 Large Machine Design
 Static Structural Analysis
 Dynamic Structural Analysis
 Electronics & Microprocessors
 Fabrication & Machining
 Programming
 Remote Controlled and Autonomous Aircraft

Wayne Holt
Small Machine Design

Wayne Holt
Positioning Gimbal for Airborne Internet Access
Situation
The incumbent airborne product was prone to failure and performance degradation due to aircraft dynamics and the effects of external
shock and vibration.
Obstacle
Produce a product that must occupy the same or less volume than the incumbent but still be tougher, more dependable and cost less.
Action
I designed a new robust positioning gimbal that employed more raw material to achieve the required dependability. The additional raw
material and its associated growth in volume was negated by utilizing a “virtual” axis of rotation where no physical drive components such
as bearings, motors, etc. resided on the axis of rotation. These components resided in a more favorable location that would not adversely
affect the total swept volume of the assembly.
In addition, I conceptualized and employed a new and novel technique for achieving the required component rotations without using
traditional, high-cost turntable bearings.
Result
The gimbal and its payload was proven more ruggedized than the incumbent through physical testing on a vibration table and through
accumulation of hundreds of hours of actual flight data. The total swept volume of the gimbal and its payload was shown to comply with
the original volume through testing and detailed measurements.
Reduced the overall product cost by approximately $2,000 or 7% by replacing the more costly turntable bearings with multiple spherical
nylon rollers. The design resulted in the award of a patent for the use of rollers in an antenna assembly.
Patent No.: US20090058745 A1
Skills Utilized
SolidWorks CAD, designing, finite element analysis, inventing, engineering, corresponding, editing, presenting ideas, writing, computing,
documentation, developing procedures, testing, measuring, research, assembly, troubleshooting, problem solving, implementing, decision
making.

Wayne Holt
Positioning Gimbal for Airborne Internet Access
Main rotation axis
Multiple spherical nylon rollers
Virtual rotation
axis for payload

Wayne Holt
Positioning Gimbal for Explosive Shock Environment
Situation
The United States Navy required a communications platform for data transfer between aircraft carriers and their assigned aircraft during
flight operations. However, the platform’s size was constrained by a defined allowable volume. The volume constraint could not adversely
affect the ability of the system to survive a heavy shock load such as would be encountered by the impact of a torpedo.
Obstacle
The allowable volume and additional packaging requirements impinged upon the space available for structural components that would
facilitate survival from a heavy shock impact.
Action
I employed a unique single-arm geometry configuration that allowed for reduced weight and volume of all motion control and radio
frequency components. I then optimized the strength of the remaining structural components through a combination of simulation, analysis
and physical testing.
Result
The communications assembly successfully completed both medium-weight and heavy-weight shock testing per MIL-S-901 testing
requirements. It also successfully completed operational vibration testing per MIL-STD-167 testing requirements.
Over 30 units were successfully deployed on naval aircraft carriers.
Skills Utilized
SolidWorks CAD, designing, engineering, corresponding, editing, presenting ideas, writing, computing, documentation, developing
procedures, testing, measuring, research, assembly, troubleshooting, problem solving, implementing, decision making.

Wayne Holt
Positioning Gimbal for Explosive Shock Environment
MIL-S-901 Heavy-weight shock testing

Wayne Holt
Transportable Positioning Gimbal for Ground Operations
Situation
The United States military required a communications platform for data transfer between aircraft in flight and troops on the ground. The
platform’s overall size was governed by the data transmission requirements; however, it had to be easily transportable via commercial or
military airlines during deployment. In addition, it had to be rugged enough to endure rough shipping and handling and still operate
afterwards.
Obstacle
The overall size was too large for easy shipping and handling especially during military ground operations. A smaller package would have
adversely affected its ability to survive rough handling.
Action
I engineered a modular electro-mechanical gimbal and payload that could be quickly and easily assembled and disassembled in the field.
The assembly was designed to be transported in six separate pieces each weighing no more than approximately 40 lbs.
Instead of traditional fastening hardware (i.e. screws, bolts, nuts), I utilized large barrel clamps at the various interfaces between structural
components to facilitate quick assembly and disassembly.
Result
The gimbal, payload and all electronics could be assembled and operational in less than 5 minutes. In addition, each shippable component
was small, light and rugged enough to be transported by military personnel and airline baggage handlers.
Skills Utilized
SolidWorks CAD, designing, engineering, corresponding, editing, presenting ideas, writing, computing, documentation, developing
procedures, testing, measuring, research, assembly, troubleshooting, problem solving, implementing, decision making.

Wayne Holt
Transportable Positioning Gimbal for Ground Operations
Barrel clamp

Wayne Holt
Collapsible Positioning Gimbal for Low-Profile Applications
Situation
The broadcasting industry required a smaller, lighter and more cost-effective gimbal and radio frequency payload for mobile broadcasting.
These products are typically mounted atop vehicles such as vans or trucks and are required to have a very low profile in order to reduce wind
drag forces and prevent collisions with bridges, overpasses or similar structures found along roadways.
Obstacle
The gimbal and payload had to be collapsible for transport and deployable for broadcasting. A highly successful and competitive design was
protected by patents and could not be employed without significant licensing costs.
During development, a vendor for a critical sub-component was not being responsive to the needs of the program. Since this vendor was
essentially single-source, the situation had a significant impact upon the success of the product.
Action
I incorporated a unique drive-train design using harmonic drives to reduce size and weight but also provide the high torsional stiffness
required to maintain pointing accuracy.
Additionally, I implemented weekly conference calls and on-site visits to increase communication and solve technical issues as a
partnership.
Result
The product met the cost target of $15,000 and the weight requirement of 135 lbs.
Skills Utilized
Oversight, management, SolidWorks CAD, designing, engineering, corresponding, editing, presenting ideas, writing, computing,
documentation, testing, measuring, research, assembly, troubleshooting, problem solving, implementing, decision making.

Wayne Holt
Collapsible Positioning Gimbal for Low-Profile Applications
Deployed gimbal and payload
Collapsed gimbal and payload
Prototype assembly on
mobile platform

Wayne Holt
Dual Encoder Assembly for Redundancy and Accuracy
Situation
The National Radio Astronomy Organization required a position feedback mechanism for one of their gimbals that had a very high Mean
Time Between Failure (MTBF) value.
Obstacle
The encoders used for position feedback had an MTBF value significantly lower than the customer requirement. The design of the encoder
could not be modified sufficiently to meet the requirement.
Action
I designed a dual off-axis encoder mechanism for redundant position feedback that incorporated two encoder packages driven from a single
spindle and friction wheel. A small anti-backlash gear train was designed to connect the two encoder packages to the common spindle. The
common spindle was then connected to a friction wheel that rolled along the inner bore of a 5 ft diameter turntable bearing. This eliminated
any backlash between the assembly and the prime mover.
Result
The mechanism achieved the required MTBF value through redundancy of the low MTBF components. It also achieved high position
feedback accuracy for the positioning gimbal due to the absence of backlash within the mechanism.
Skills Utilized
AutoCad software, designing, engineering, corresponding, editing, presenting ideas, writing, computing, documentation, testing, measuring,
research, assembly, troubleshooting, problem solving, implementing, decision making.

Wayne Holt
Dual Encoder Assembly for Redundancy and Accuracy
Dual encoder
packages
Friction wheel
Anti-backlash gearing

Wayne Holt
Large Machine Design

Wayne Holt
Large Electro-Mechanical Positioning Gimbal and Payload
Situation
A popular satellite television provider required a new ground station for uplink of high definition television signals. The gimbal payload was
required to house a full compliment of passive and active radio frequency equipment that produced approximately 24,000 BTU/hour of heat.
Additionally, the customer wanted to increase the operating life of the actuator that controlled the angular position of the payload.
Obstacle
The heat generating components were all housed within an enclosed volume located on the rotating portion of the gimbal. This heat needed
to be removed while maintaining the weather resistance of the enclosure.
Also, the load on the elevation axis actuator was defined by the weight of the payload and the wind forces imparted to the payload in speeds
as high as 125 mph. Reducing the payload weight or changing the survival wind speed requirement was not an option.
Action
I constructed a redundant cooling system that provided cold air to the enclosed volume. Two air conditioning units were located on a
moving platform and the cold air was provided to the enclosure via two insulated, flexible ducts routed across another rotating interface.
I also incorporated large counter-balancing arms on the payload in order to reduce the loads on the elevation actuator.
Result
The electronics enclosure was able to maintain an internal temperature of approximately 80 degrees Fahrenheit while the equivalent of two
residential ovens produced heat inside. Also, the loads on the elevation actuator were reduced sufficiently in order to increase the operating
life of the actuator by approximately 20%.
Skills Utilized
Heat transfer, thermodynamics, SolidWorks CAD, designing, engineering, corresponding, editing, presenting ideas, writing, computing,
documentation, testing, measuring, research, assembly, troubleshooting, problem solving, implementing, decision making.

Wayne Holt
2 ton military grade HVAC units.
One nearside and one farside.
Counterweight arms.
One nearside and one farside.
Insulated flexible ducting.
Electronics enclosure.

Wayne Holt
Situation
The United States government required a large electro-mechanical positioning gimbal with an 11 meter diameter radio frequency reflector
payload. The entire structure was required to be of sufficient stiffness to achieve a challenging pointing accuracy.
Obstacle
Normal gimbals of this size have a stiffness that will produce a drive train fundamental resonance mode of 2 Hz. This gimbal required a
drive train fundamental stiffness of 5 Hz in order to meet the required pointing accuracy. Since the natural frequency is equally dependent
upon stiffness as well as mass in the relationship , achieving a 2.5X increase in fundamental frequency simply by adding more
steel can reach a point of diminishing returns.
Action
I supervised the assigned contract mechanical designer and contract structural analyst and facilitated the communication between these two
individuals as they iterated the design back and forth. We solved the problem by increasing the steel plate thickness but also by specifying
and purchasing drive train components with very high torsional stiffness values.
In addition, I spent 9 weeks onsite as the lead engineering representative supervising and participating in the assembly process. I worked
closely with the customer and their field technicians to solve various installation challenges and was able to meet the scheduled assembly
deadline.
Result
The gimbal provided the necessary 5 Hz drive train fundamental mode and was verified by onsite testing and measurements.
Skills Utilized
Oversight, supervision, conflict resolution, corresponding, problem solving, decision making, field assembly, 2D and 3D AutoCad software,
designing, analysis, engineering, editing, presenting ideas, writing, computing, documentation, testing, measuring, research, troubleshooting,
implementing.
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Wayne Holt

Wayne Holt
Static Structural Analysis

Wayne Holt
Static Structural Analysis of Positioning Pedestal Using Nastran
Situation
Customer required an electro-mechanical positioning gimbal, foundation support structure and payload that would operate in wind speeds of
45 mph gusting to 60 mph and survive without damage in wind speeds of 125 mph. The assembly was also required to point accurately
when exposed to solar heat flux of 1100 W/m2
.
Obstacle
Since this was a new design effort, no previous verification had been done to ensure that the design would satisfy the environmental
requirements.
Action
I performed all structural analysis utilizing the finite element software FEMAP and NX Nastran. I also generated the geometry required for
the finite element analysis with SolidWorks CAD software which I then imported into FEMAP in order to mesh.
I applied the wind loads as static, steady-state forces resolved to the three payload interface locations at the top of the gimbal. Wind loads
were determined from wind tunnel testing performed by NASA JPL in the late 1960s for similar payloads. Loads, stresses and deflections
were evaluated with respect to material allowable stresses and allowable deflections.
In addition, I applied solar heat flux loads asymmetrically in order to determine the effects that uneven thermal expansion would have on the
pointing accuracy of the payload.
Result
The gimbal and its payload successfully met the pointing accuracy required for satellite tracking as well as satellite command and telemetry.
Skills Utilized
FEMAP finite element model creation, static finite element analysis with NX Nastran, heat transfer finite element analysis, corresponding,
problem solving, decision making, SolidWorks CAD software, designing, engineering, editing, presenting ideas, writing, computing,
documentation, research, troubleshooting, implementing.

Wayne Holt
Static Structural Analysis of Positioning Pedestal Using Nastran
Component
Maximum Stress
(psi)
Margin against al-
lowable stress
Margin against
yield strength
Base flange 8947 238% 306%
Riser wall 22837 32% 59%
Riser bulkhead 13218 129% 175%
Riser gussets 30085 1% 21%
Bearing adapter plate 8304 264% 337%
Riser top flange 25998 16% 40%
Static Wind Loading
Pitch
(deg)
Yaw
(deg)
Roll
(deg)
BRE
(deg)
Rear Illumination 0.0750 0.0000 0.0001 0.0750
Solar Thermal Loading

Wayne Holt
Static Structural Analysis of Gimbal Payload Using ANSYS
Situation
A new product development effort for broadband internet required an electro-mechanical positioning gimbal, foundation support structure
and payload that would operate in wind speeds of 30 mph gusting to 45 mph and survive without damage in wind speeds of 125 mph. The
surface accuracy of the radio frequency reflector payload was also not to exceed 0.015 inches root mean square (RMS).
Obstacle
The contributors to the reflecting surface error consist of smaller individual errors due to fabrication, assembly and the errors induced by
wind forces. Maintaining such a small reflecting surface error with these three variables requires very precise fabrication and assembly
procedures in addition to a design that provides optimal stiffness to resist deflections caused by wind forces.
Action
I performed all structural analysis utilizing the finite element software ANSYS.
I applied the wind loads as static, steady-state forces resolved to the three payload interface locations at the top of the gimbal. Wind loads
were determined from wind tunnel testing performed by NASA JPL in the late 1960s for similar payloads. Loads, stresses and deflections
were evaluated with respect to material allowable stresses and allowable deflections.
Result
The gimbal payload successfully achieved the reflecting surface accuracy (error) of 0.015 inches RMS.
Skills Utilized
ANSYS finite element model creation, static finite element analysis, corresponding, problem solving, decision making, SolidWorks CAD
software, designing, engineering, editing, presenting ideas, writing, computing, documentation, research, troubleshooting, implementing.

Wayne Holt
Static Structural Analysis of Gimbal Payload Using ANSYS

Wayne Holt
Dynamic Structural Analysis

Wayne Holt
Dynamic Structural Analysis of Gimbal & Payload for Airborne Application
Situation
A new product development effort for broadband internet on business jets such as the Gulfstream G450, G550 or G650 required an electro-
mechanical positioning gimbal and payload that would survive without damage in sine and random vibrations environment per RTCA-DO-
160 Curves C and C1. In addition, the gimbal had to survive a saw-tooth shock pulse of 20 G for 11 milliseconds.
Obstacle
Random vibration curves C and C1 produce an equivalent acceleration of 4.12 GRMS and 5.83 GRMS respectively. Since this was a new
product unlike anything developed before, it was unknown whether the assembly would survive in these environments.
Action
I created a finite element model of the complete assembly in FEMAP and solved with NX Nastran. RMS stresses were extracted from the
model and evaluated relative to material allowable stresses as defined in the Metallic Materials Properties Development and
Standardization document (MMPDS). This document defines all the allowable stresses used in the aircraft and aerospace industry.
I also performed physical testing on a prototype unit in order to validate or adjust the finite element model results. Testing was done on a 3-
axis vibration table or shaker.
Result
The finite element model was validated by prototype testing. Material stresses and deflections remained within allowable ranges.
Skills Utilized
FEMAP finite element model creation, NX Nastran dynamic finite element analysis, corresponding, problem solving, decision making,
SolidWorks CAD software, designing, engineering, editing, presenting ideas, writing, computing, documentation, research, troubleshooting,
implementing.

Wayne Holt
Dynamic Structural Analysis of Gimbal & Payload for Airborne Application

Wayne Holt
Fundamental or Normal Modes Analysis of Gimbal & Payload
Situation
A new product development effort for broadband internet in developing countries required an electro-mechanical positioning gimbal and
payload that would maintain a challenging pointing and tracking accuracy.
Obstacle
Pointing and tracking accuracy is significantly affected by the structural and drive train torsional stiffness. A measure of stiffness can be
found in the fundamental resonance modes of the structure; however, defining all boundary conditions completely and accurately can be
challenging for components such as bearings, speed reducers and motors.
Action
I created a finite element model of the entire structure in FEMAP and solved the normal modes analysis with NX Nastran. In order to
accurately account for the effects of the drive train components and bearings, I modeled these items as linear six degree of freedom springs.
The corresponding translational and rotational spring rates were determined from similar components for which these values were either
provided by the manufacturer or directly measured from testing.
Result
The finite element normal modes analysis yielded a first (or lowest) fundamental resonance mode of approximately 7.5 Hz. Since most
similar structures have an equivalent mode at 2 Hz, this resulted in a 275% increase in stiffness and the ability of the gimbal and payload to
satisfy its pointing and tracking accuracy requirements.
Skills Utilized
FEMAP finite element model creation, NX Nastran normal modes finite element analysis, corresponding, problem solving, decision making,
SolidWorks CAD software, designing, engineering, editing, presenting ideas, writing, computing, documentation, research, troubleshooting,
implementing.

Wayne Holt
Fundamental or Normal Modes Analysis of Gimbal & Payload
Mode Description
Frequency
(Hz)
1 Yawing around azimuth axis 7.55
2 Pitching about elevation axis 8.63
3 Rolling about RF axis 11.16
4 Pitching about elevation axis 13.65
*
5 Torsion in reflector quadrapod 13.79
*
6 Reflector radial ribs 17.86

Wayne Holt
Electronics & Microprocessors

Wayne Holt
Power Supply Display
Situation
A four-channel power supply was rescued from a trash receptacle. It was operational with the exception of a noisy cooling fan.
Obstacle
The power supply was designed as a rack-mount unit and did not possess any means to easily determine the actual voltage or current
supplied for each output channel.
Action
I designed, built and integrated a display module using an Arduino Mini programmable microprocessor, four current sensors, a voltage
divider circuit, an LCD display, four multi-turn potentiometers, five banana jacks and an off-the-shelf aluminum project enclosure. In
addition, I replaced the noisy cooling fan in the power supply.
Result
I now have a four-channel bench top power supply that I frequently use with other electronics projects to supply anywhere from 5 Vdc to 28
Vdc with a current capacity of 15 amps.
Skills Utilized
Arduino programming, electronics assembly, soldering, specifying, circuit design, fabrication, wiring, integration, troubleshooting,
modifying, inventing, improving.

Wayne Holt
Power Supply Display
Original power supply
Display module
USB programming port
Potentiometers for voltage adjustment
Banana jacks for 4 channels
LCD display for voltage & current
Arduino Mini microprocessor
Current sensor

Wayne Holt
Tachometer for CNC Spindle Motor Control
Situation
Personal desktop CNC milling machine required a separate tachometer for the cutting spindle motor.
Obstacle
Integrating a hall effect sensor with the spindle motor and display device as well as providing feedback to the spindle motor controller.
Action
I engineered, built and integrated a stand-alone tachometer to the CNC milling machine using an Arduino Mini programmable
microprocessor, FTDI USB to serial converter, hall effect sensor, two neodymium magnets, an LCD display and an off-the-shelf plastic
project enclosure.
I also created the Arduino code required to read the output from the hall effect sensor, calculate the spindle motor speed, show the speed on
the LCD display and send the speed value to the spindle motor controller via a serial interface.
Result
I now have an independent, stand-alone measurement of the spindle motor speed which is fed back to the spindle motor controller in order to
create a closed-loop velocity correction.
Skills Utilized
Arduino programming, serial to serial communication, motor control, electronics assembly, soldering, connectorizing, circuit design,
fabrication, wiring, integration, troubleshooting, modifying, inventing, improving.

Wayne Holt
Tachometer for CNC Spindle Motor Control
Display module containing
the microprocessor
Serial interface connector
Hall effect sensor CNC spindle motor
Neodymium magnet
Arduino Mini microprocessor

Wayne Holt
FM Radio Transmitter
Situation
I required a method of transmitting an audio signal from my smart phone to the radio in my automobile.
Obstacle
The OEM radio was manufactured in 2002; consequently, it did not have any provisions for auxiliary audio input except for compact disc.
Action
I conceived and created a device that would receive the input audio signal from the smart phone via a standard 3.5mm audio cable and jack
and transmit that signal to the stock radio via a standard FM broadcast frequency. While similar devices already exist off-the-shelf, I wanted
to learn and create my own using an Arduino Uno programmable microcontroller, an FM radio transmitting shield and a stereo audio input
shield.
I integrated these three main components into a modified off-the-shelf aluminum project enclosure and created the code required to read the
input audio and direct it to the radio transmitting shield.
Result
I was successful in transmitting audio from my smart phone to the vehicle radio; therefore, I could finally listen to audiobooks stored on my
phone while commuting to and from work.
Skills Utilized
Arduino programming, electromagnetic interference (EMI) reduction, electronics assembly, soldering, connectorizing, circuit design,
fabrication, wiring, integration, troubleshooting, modifying, inventing, improving.

Wayne Holt
FM Radio Transmitter
Arduino Uno microprocessors
Audio input jack from
smart phone
Power button
Status LED
FM transmitter shield
Sound board

Wayne Holt
Battery Charger Power Supply
Situation
I required a method of reducing 12 volts DC to 6 volts DC in order to power a single cell lithium polymer battery charger.
Obstacle
An existing lithium polymer battery charger required 6 volts DC in order to operate; however, this voltage is not readily available in an
outside environment such as a radio controlled aircraft flying field. What is readily available is 12 volts DC from an automobile battery;
therefore, converting the 12 volts to 6 volts was required.
Action
I built a standard voltage divider circuit utilizing two high-power ceramic resistors to convert 12 volts into 6 volts. Since the power resistors
dissipate a significant amount of heat, I integrated two small DC cooling fans to remove excess heat.
Result
I was able to charge a single cell (1S) lithium polymer battery from my automobile battery while at the RC aircraft flying field.
Skills Utilized
Electronics design and assembly, soldering, connectorizing, circuit design, fabrication, wiring, integration, troubleshooting, modifying,
inventing, improving.
Voltage divider assembly

Wayne Holt
PCB Design & Fabrication
Situation
I required a printed circuit board for a DIY linear adjustable voltage regulator I designed.
Obstacle
No previous experience designing or fabricating a printed circuit board (PCB).
Action
I designed the PCB layout using Eagle PCB design software. After researching the fabrication methods for creating printed circuit boards, I
acquired the necessary materials including ink jet printable transparency, photosensitive copper plated board, copper etching chemical and
anultraviolet light. I then fabricated the PCB and populated it with the necessary electrical components including LM317 voltage
regulators, heat sinks, potentiometers, various resistors and connectors.
Result
The PCB fabrication was successful and the finished, populated board performed as designed regulating voltage between 12 Vdc and 24
Vdc.
Skills Utilized
Eagle PCB design software, CircuitLab online circuit simulation software, PCB fabrication, electronics assembly, soldering, connectorizing,
wiring, integration, troubleshooting, modifying, inventing, improving.

Wayne Holt
PCB Design & Fabrication
Ink Jet Transparency
Exposed Copper Board
Completed PCB

Wayne Holt
Fabrication & Machining

Wayne Holt
Design, Fabrication and Operation of a Personal CNC Mill
Situation
Wanted to build my own CNC (computer numerically controlled) milling machine for DIY projects.
Obstacle
While kits were available for purchase from various retailers, I wanted to build my own in order to learn new skills that I had never
attempted. The major challenge was fabricating the main aluminum structural components with a high degree of accuracy.
Action
I conceptualized the design of the milling machine taking design elements from various machines built by others. I modeled the machine in
SolidWorks CAD software. I purchased the raw aluminum plates cut close to size and finished the machining on my own. I specified all off
-the-shelf components such as stepper motors, couplings, motor controllers and limit switches. I modified a computer ATX power supply to
provide a consistent 12 Vdc to the stepper motors and controllers. I then assembled the machine, installed the necessary Mach 3 operating
software, installed the CamBam CAM (computer aided manufacturing) software and configured the Dynomotion Kflop motion controller
for 3-axis operation.
Result
Successfully machined a number of parts in various materials such as high-density foam, wood, machining wax and aluminum. In addition,
I significantly increased my knowledge and skills in machining and design for manufacturing (DFM).
Skills Utilized
Aluminum fabrication, specifying, assembly, CamBam CAM software programming, Mach 3 machine programming, motion control tuning,
design for manufacturing, electronics assembly, soldering, connectorizing, wiring, integration, troubleshooting, modifying, inventing,
improving.

Wayne Holt
Design, Fabrication and Operation of a Personal CNC Mill

Wayne Holt
Additive Fabrication—3D Printing
Situation
Needed a method of removing machining debris and shavings from the CNC milling bed.
Obstacle
Machining debris occludes visual inspection of a part during the fabrication process. In addition, it can interfere with the machining
operation by allowing excess heat to build up around the end mill.
Action
I conceived a design for an attachment that could be mounted to the spindle motor and connected to a shop vacuum to constantly remove
debris from the milling bed. I modeled the part in SolidWorks CAD software then sliced the model using Makerbot 3D printing software. I
then printed the part on a Makerbot Replicator 2 utilizing ABS plastic material and a dissolvable printing substrate to support the interior
volumes. After printing, the substrate was dissolved using Limonene solvent.
Result
Successfully fabricated the vacuum attachment and used it to remove machining debris from the CNC mill.
Skills Utilized
SolidWorks CAD software, Makerbot desktop printing software, Makerbot Replicator 2 operation, design for manufacturing, integration,
troubleshooting, modifying, inventing, improving.
Dissolvable filament
CNC spindle motor location
Vacuum hose attachment location
Removable “helper” pads
to prevent edge curl

Wayne Holt
Programming

Wayne Holt
Visual Basic for Custom Engineering Tools
Situation
The engineering department needed a basic set of industry specific tools for calculating various entities such as fixed or floating fastener
tolerance, unit conversion, equivalent wind speed, coordinate rotations and etc.
Obstacle
Provide these tools in a format that is universally recognized and intuitive to use.
Action
Since most every engineer is proficient in the use of Microsoft Excel spreadsheet software, I developed a Visual Basic add-in for Excel that
provided the user with interactive input and output screens for various engineering tools. Prior to this effort, I had very little experience
programming in Visual Basic; therefore, in the course of approximately 2 months I studied, researched and taught myself to program in this
language.
Result
Successfully disseminated the Excel add-in to the entire engineering department as version controlled software. Reduced manual calculation
times for these tools by approximately 50%.
Skills Utilized
Microsoft Excel, Visual Basic object oriented programming, debugging, troubleshooting, modifying, inventing, improving, writing
procedures, presenting.

Wayne Holt
Visual Basic for Custom Engineering Tools

Wayne Holt
Arduino Programming
Situation
Desired to create a mechatronic prop for a Halloween event.
Obstacle
Integration of a multitude of features or functions that must work together both in software and hardware.
Action
I purchased a skull prop from a local retailer for $5 and incorporated Arduino hardware and programming for motion control and special
effects. I included an Arduino Mini programmable microcontroller, two large hobby servos, an audio amplifier shield, an audio recording
shield, two small LCD screens, steampunk welding goggles and LED lighting. I also designed and built a pendant that could be used to
operate the various functions such as moving the jaw, rotating the head and playing a customized audio clip. All functions were controlled
by a single Arduino sketch which I wrote.
Result
Successfully created the mechatronic prop which in addition to the functions listed above could also “move” that were displayed in each of
the two LCD screens located in the goggles. I won a prize of a $50 gift card for my effort.
Skills Utilized
Arduino programming, servo operation and integration, debugging, fabricating, electronics integration, mechanism design, troubleshooting,
modifying, inventing, improving.

Wayne Holt
Arduino Programming
Arduino code
Jaw servo and mechanism
Speaker
Arduino micro-
processor and
recording shield
Goggles with
LCD screens
LED lighting strip
on copper tube
Handheld user pendant
Joystick for
motion control
Momentary switches
for audio playback

Wayne Holt
Remote Controlled and Autonomous Aircraft

Wayne Holt
Autonomous Multi-Rotor Aircraft With Groundstation
Situation
Wanted a challenging project that would expand my knowledge and skillset.
Obstacle
Autonomous multirotor aircraft were just beginning their entrance into the market and the associated control systems were still essentially
experimental. In addition, I had very little experience with building and flying remote controlled aircraft much less any knowledge of
control system algorithms such as proportional-integral-derivative (PID).
Action
I purchased and assembled a multirotor aircraft kit with six rotors, also referred to as a hexacopter, from 3D Robotics in San Diego. The kit
contained all components necessary to build the aircraft including the onboard autopilot and stabilization microprocessor based on the
Arduino platform. I subsequently tested the aircraft under controlled manual flight. I eventually added an inertially stabilized onboard video
camera, 3D printed camera gimbal, 5.8 GHz video transmitter and an onscreen display device to allow first person view (FPV) flight.
In addition, I constructed a ground station for monitoring and control of the aircraft. The groundstation contained an onboard power supply,
laptop computer running the autopilot software, LCD monitor, 5.8 GHz video receiver, 5.8 GHz circularly polarized antenna, 5.8 GHz patch
antenna and a 2.4 GHz patch antenna for aircraft control. The components were housed inside a repurposed music instrument case and
mounted on top of a surveying tripod.
Result
I have successfully flown the aircraft multiple times utilizing FPV video in manual mode as well as fully autonomous mode.
Skills Utilized
Airborne stabilization, brushless motor operation and integration, video transmitting & receiving, onboard power budgeting and monitoring,
antenna theory, servo operation, assembly, GPS positioning, debugging, fabricating, electronics integration, troubleshooting, modifying,
inventing, improving.

Wayne Holt
Autonomous Multi-Rotor Aircraft With Groundstation
Groundstation
Flight video display
Laptop computer
Power monitoring
display
Video
receiver
Hexapod aircraft
Stabilized camera
gimbal
GPS module
Video transmitter
& antenna

Wayne Holt
Ornithopter
Situation
I’ve always been fascinated by mechanical simulation of natural flight. When I discovered a design for a flapping aircraft or ornithopter, I
could not resist the temptation to build and fly one.
Obstacle
Ornithopters are finicky about flying well. This particular design could generally achieve powered flight in light winds to provide lift;
however, it would not glide unpowered. The wings would simply move to the “top dead center” location and the aircraft would plummet to
the ground.
Action
After I assembled the ornithopter and performed a number of test flights, I specified and installed a glide controller consisting of a hall effect
sensor, a single neodymium magnet and a small microprocessor. The hall effect sensor and microprocessor would sense the position of the
magnet mounted to the wing flapping mechanism and consequently determine the position of the wings. It would then command the main
brushless motor that powered the entire ornithopter to a defined glide position and engage the brake feature on the electronic speed controller
in order to hold position.
Result
The ornithopter successfully achieved unpowered gliding flight.
Skills Utilized
Position sensing, mechanism design, brushless motor operation and integration, servo operation, assembly, debugging, fabricating,
electronics integration, troubleshooting, modifying, inventing, improving.

Wayne Holt
Ornithopter
Hall effect sensor
Neodymium magnet
(mounted inside flapping gear)
Wing flapping
mechanism
2.4 GHz
transceiver
Revised wing design with
articulating wing mechanism
Ornithopter

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