smart skateboard by xiuliliaofz


									What do you get when you build the
world’s first ever hands-free electric
skateboard? You get …


                                   AME 490
                     University of Southern
                          Viterbi School of

                               Ben Forman
                              Geoff Larson
                             Kristin Inouye
                                 Niel Chen
Meet the SMRTboards team:

Ben Forman
Ben Forman is a senior Mechanical Engineering student at the University of Southern California
where he specializes in Robotics. Over his time at USC he has gained experience with both large
and small scale robots, working on everything from hospital room sized medical robots to
handheld consumer products. Last year he captained his team to a second place finish in the year
ending USC "Search and Rescue" Robotics Competition. Over the past three summers he has
worked in the medical robotics field and also spent time interning at a product design firm where
he learned to mesh outside-the-box creativity with inside-the-box practicality.

Geoff Larson
Geoff Larson is a senior at the University of Southern California, majoring in Mechanical
Engineering with a minor in Business Entrepreneurship. His intended concentration is Product
Design and Manufacturing. Geoff currently holds the position of Vice President at Automotive
Dezignz, LLC, working with new product design and event organization such as his company’s
May 2007 Los Angeles Mustang Cruise. He specializes in Computer Aided Design (CAD) as a
Certified SolidWorks Associate (CSWA), and mobile audio-visual applications as both a Mobile
Electronics Certified Professional (MECP) Advanced Installer and Mobile Products Specialist.
 He also has an extracurricular background in radio-controlled vehicle modification, semi-
autonomous robot construction, speaker enclosure design, and die-cast modeling.

Kristin Inouye
Kristin is a 3rd year Electrical Engineering student at the University of Southern California. She
is has been accepted into the Progressive Degree Program at USC and will graduate in December
2010 with her Bachelor's and Master's Degree. From interning at a private engineering
consulting firm titled ECS, Inc., she has been able to effectively apply the skills she acquired in
college, as well as discover other qualities, such as the business side to engineering. In the
future, she hopes to contribute innovative and ground-breaking ideas that will make the world
more self-sufficient.

Niel Chen
Neil is a senior at the University of Southern California, majoring in Electrical Engineering. Neil
has worked with various programmable mobile robots and programming languages including
object-oriented and hardware description languages.

What is the SMRTboard?
The SMRTboard is a hands-free Electric Skateboard. When the rider leans forward, the board
accelerates. When the rider leans backwards, the board decelerates. From what we know, this is
the first board of its kind.

How does it work?
The rider places their feet on the two
wooden pressure pads on the deck of the
board. These pads each lie on three rubber
stilts or legs. Each of these legs lies on a
force sensor. The summation of the front
three sensors is compared to the back three.
If it is determined that there is more weight
on the frontal pressure pad, the SMRTboard
will accelerate. This process is explained
further in later sections

                                  What are the Specs?
                                      Top Speed: 15 miles/hour
                                     Range: 45 mins or 4-5 miles
                                          Weight: 35 pounds.

What is on the SMRTboard?

              A: Motor
              B: Chain
              C: Drive Wheel
              D: Rear Pressure Pad
              E: Frontal Pressure Pad
              F: Trucks
              G: Arduino (Brain)
              H: Battery
              I: Speed Controller
              J: Spine
              K: Front Wheels

                                                     TOP            BOTTOM

System #1: Propulsion
The propulsion system is made up of the motor, battery, drive chain, and the drive wheel. This
system takes inputs from the speed controller and converts them into propulsion.
The SMRTboard is equipped with a 24 Volt, 500 Watt electric scooter motor. It is mounted to
the top of the board on an aluminum mounting plate. This was done to insure decent ground
clearance. The motor is placed off center in order to insure that it lines up vertically with the gear
on the drive wheel’s axle. This causes the board to tip slightly when observed but no such tilt is
visible when a rider is on board. This tilt also goes unnoticed when riding the board.

A seven cell, 25.9 Volt Lithium Ion battery powers this motor. Lithium Ion batteries were chosen
because they are lighter, smaller and stronger than the batteries on electric boards currently on
the market. Our battery weighs less than six pounds while competitor’s weigh up to 20. The
battery has a life of 45 mins.

An electric scooter chain is used to translate the force from the motor to the drive axle. The gear
ratio used between the motor and rear axle had a great effect on the speed and acceleration of the

Drive Wheel:
The SMRTboard uses a single 8-inch rubber, pneumatic electric scooter wheel. Whereas every
other board has four wheels, the SMRTboard only has three. This was done intentionally and it
impacted several other factors of the board’s design. The main reason we chose a singular drive
wheel was to avoid dealing with attaching a chain to a set of trucks. Trucks are designed to fled
and deform when leaned on. This is great for turning but would’ve been a headache when it
came to attaching a chain. The slack of the chain would constantly be changing and it would
likely fall off consistently. Other powerboards have rear trucks with a motor attached in such a
way that the motor moves with the trucks. This exposes the motor to damage from road surfaces
and inconsistencies with belt or chain slippage as described, and when turning aggressively, can
even lift the powered wheel off the ground in complete loss of traction.
To solve these issues, and simplify the design of the drive system, the SMRTboard incorporated
a single, centered rear drive wheel, powered by a motor mounted firmly to the chassis of the

         When leaned on, the axle of our single wheel remains stationary but the wheels contact
point with the ground moves. When turning, the wheel compresses to one side and the wheel
leans like a motor cycle. This is far different than a conventional skateboard where all 4 wheels
stay firmly on the ground at all times. The SMARTboard thus does all of its steering with the
front trucks and the back drive wheel simply follows them.
System #2: Steering
The steering system is made up of the front trucks and the front wheels.

Front Trucks:
Skateboard trucks serve two main functions on a board: provide stability at speed and in turns,
and act as the steering mechanism for the rider. In going with a completely hands-free design,
skateboard trucks were essential to allowing the rider to steer the board simply by changing his
weight distribution from side to side. Leaning to the left turns the wheels to the left, and leaning
to the right turns them to the right, as shown in the figure below:

Turning radius was negatively affected by the elimination of rear trucks that provide compound
steering on other boards. Additionally, the wide deck of the SMRTboard resulted in tipping of
the board under aggressive turning, shown below:
To fix these issues, Original S10 trucks were installed. Their added width, combined with wide
wheels eliminated stability issues because the rider’s center of mass was always located within
the planar boundaries of the edges of the wheels’ contact patches with the ground. Additionally,
the greater angular travel allowed much sharper turning than standard trucks.

The SMARTboard has 250 mm wide trucks. This is wider than 99% of boards on the market.
The extra width increases stability while decreasing the boards turning radius. The trucks are
bolted to the underside of the board’s spine, which is explained later.

Front Wheels:
Attached to the trucks are ABEC 11 wheels. These are the largest commercially available
wheels. Large wheels allow the board to go over rocks and cracks without compromising the
smoothness of the ride. The wheels also have built-in bearings which allow the board to coast.
System #3: Structure
The structural stability is extremely important as any amount of flex in the deck could not only
discomfort the ride, but also throw off all sensing. The structural system is made up of the deck,
the motor mounting plate, the spine, the nose, and the axle rails.

The deck is made up of a composite of aluminum and ply wood. It is a five layer design intended
to both provide support and dynamic looks (Our team’s jagged “S” logo is incorporated into the
board’s center). The brown layers seen below are 1/4th inch plywood while the grey layers are
1/8th inch aluminum. Aluminum was used for its light weight and high strength characteristics.
All wooden parts on top of the board that were visible were given a dark cherry wood stain to
enhance their look. The visible aluminum elements of the deck were sanded with heavy, than
light sandpaper to give them a brushed metal look.

Motor Mounting Plate:
This sits off the back of the board (to the right in the above picture). We wanted to make sure we
attached the motor to metal as those screws would likely be receiving the most stress and torque.

The spine is the most important element of the structural system. Its thick aluminum C-shaped
construction is near impossible to flex. This means that riders up and over 200 lbs can ride our
board without having to worry about their weight causing the underside electrical components to
drag on the ground. The spine was also useful in that it protected these electrical components.
Axle Rails:
2 more aluminum C-shape beams (much thinner than the spine) were run from the front of the
board to its rear. These delivered additional structural support and provide the rear axle and a
strong place to sit.

                                  The nose was mostly a cosmetic addition to make the board
                                  look sleek. Considerations were made to insure that the front
                                  wheels would not touch the nose in even the hardest of turns.
                                  The nose received a deep cherry wood stain like the pressure

System #4: Sensing and Processing
The sensing system is made up of the frontal and rear pressure pads, the six force sensors, and an
integrated circuit, a microcontroller, and a speed controller.

Pressure Pads:
The front and real pressure pads were cut into triangle-like shapes due to the three points of
contact are needed to triangulate a force. The pressure pads are composite like the deck with
wooden surfaces and aluminum undersides. This was to insure that they wouldn’t flex under the
rider’s weight. If these pads were to flex and bottom out then all sensor readings would be
negatively affected.

The pressure sensors feed readings into a microcontroller (named the “Arduino”), mounted to the
bottom of the board, which then outputs a voltage based on the reading into the speed controller.

Speed Controller
The speed controller takes the voltage input from the microcontroller, which can output up to 5
volts, and relays 4.8 times of that voltage from the battery to the motor.

With our $500 budget and available tools, it was more feasible to create a skateboard with a
feed-forward system than one of a feedback system. The Arduino responds to the input signal
from the force sensors in a predefined way. It does not take into account how its output affects
the rider’s balance, which in turn affects the output, and so on. Since this is a feed-forward
system, we avoided any undesirable infinite feed-forward loops in the programming. The smart
skateboard accelerates only when more weight is placed on the front of the skateboard than on
the back. The rider must lean forwards in order to get the skateboard to accelerate. The
acceleration of the skateboard will make it difficult for the rider to fall farther forwards. An
undesirable feed-forward loop would be created if the input required to make the skateboard
accelerate were the circumstance in which the rider places more weight on the back. In that case,
the rider leans backwards, causing the skateboard to accelerate, which in turn causes the rider to
lean farther backwards, and so on, until the rider falls off of the skateboard. Our design avoids
this problem.

Requirements of the Feedback System:
A feedback system would require substantially more sensors and of different kinds. It would
require more pressure sensors and a way to mount them precisely and measure any changes in
the quality of mount as time goes on. It would also require sensors within the wheels and an
accelerometer. In order for the smart skateboard to determine how it is affecting the rider, it
needs to take measurements as fast as possible on the torque in each wheel, center of mass of the
rider, acceleration of the center of mass of the rider, position of the rider’s feet, and three-
dimensional acceleration of the skateboard. However, the center of mass of the rider cannot be
measured by the skateboard, or for that matter, by any platform a person can stand on. Only the
projection of the center of mass into the plane of the platform can be measured. Therefore, mean
height of the potential riders will need to be assumed. Furthermore, there will be no way for the
skateboard to determine the bodily orientation of the rider, such as the extent to which the rider
flails around to balance himself, other than that of the base of his feet. Therefore, such a
feedback skateboard, at best, would only be stable in self-balancing within a certain range of
rider’s bodily orientation.
Requirements of a More Advanced Feed-Forward System:
We could have made a more complicated feed-forward system with the equipment we have, but
decided it is not a plausible design. Theoretically speaking, we could have estimated the torque-
current relationship of the scooter motor. Since torque, radius of rotation, and force are related
     
by   r  F , given the torque-current relationship and the radius of the scooter wheel, we could
have found the force applied by the wheel given a particular current. This would require an extra
input to the Arduino to measure the current. Force, mass, and acceleration are related
            
by  F  ma . It is also possible to find the moment of inertia of the rotating portion of the

motor if its exact dimensions are known. For our case, we would need to take it apart to
determine the exact dimensions. Angular acceleration can also be found. The mass of each
skateboard component can be determined by using scales. Experiments can determine the
coefficients of friction between the skateboard wheels and the ground. The ABEC 11 Fly Wheels
have measurable dimensions, so their moments of inertia can be determined. This would give us
enough information, at least in the case of a one-dimensional travel path of an unmanned
skateboard to theoretically determine the acceleration of the entire skateboard without the use of
an accelerometer.

It becomes more complicated in the three-dimensional case. Since the skateboard can be turned
if enough force were applied to cause the trucks to swivel and the skateboard to tilt sideways, the
two-dimensional case will be more mathematically involved. Among other things, parameters of
the trucks will need to be determined.

The mass of the rider can be measured on-the-fly by the force sensors. The mean height of the
potential riders can be assumed.

There are some problems and difficulties with the hypothetical, complicated design. Our scooter
motor did not come with any torque-current specifications. It is something that fit our budget, not
something sold as a high precision instrument. A solution may be to use a torque wrench while
controlling the current to find the torque-current relationship. However, this relationship will
inevitably vary in practice. It can change under stress. Battery conditions will also affect the
system. The rider has no way to predict this variability. This is one of the reasons that neither of
us will want to ride such a skateboard. In general, the more variability a device has in practice,
the more unstable it can become during usage. Therefore, it is always better to use a feedback
system. If it is not possible to use a feedback system, the variability of the feed-forward system
will need to be reduced.

Since our budget and available equipment resulted in a feed-forward system, the best we can do
is to minimize the variability of the skateboard’s behavior. That is why we decided to write the
program only taking into account the amount of weight the rider places on the front plate and on
the back plate. Although the rider may not have read the source code, the skateboard’s behavior
is only a function of one thing rather than many, so the rider will have an easier time
experimenting and figuring out how to balance. If the skateboard’s behavior were instead a
function of ten different things, it would be that much harder for the rider to figure out all the
combinations of postures needed to balance.

Our design uses 3 rubber spacers attached to each plate. We used spacers so that they will be in
good contact with the sensors. Without the spacers, only a very small percentage of the rider’s
weight will be measured by the sensors since most of the weight will be distributed between the
plates and the deck rather than on the spacers. We used 3 spacers because 3 points define a
plane; so the 3 spacers would necessarily hold the sensors in contact with the deck. We used
rubber spacers because rubber is elastic and ensures that they will sink down into contact with
the sensors. Very technically speaking, the spacers have surface area, so many points on each
spacer will be in contact, and therefore the 3 spacers combined will have more than 3 points in
contact with the sensors. That is why we chose rubber as the material for the spacers. If instead,
we used a perfectly rigid material for the spacers, then we need to find a way to make them
perfectly coplanar. Otherwise it is possible for one of them to balance on its own or for all of
them to not be in total area contact with the spacers. Using fewer spacers per plate would result
in poor design. The number of spacers less than 3 would be less than or equal to the number of
points without sensors on the deck that the plates will be in contact with. Then there would not
be a way to measure the rider’s weight on each plate. Using more than 3 spacers per plate is also
not a good idea for our design. Since 3 points define a plane, it would be difficult to get all the
other spacers perfectly coplanar or at least in acceptable contact.
The Overall Electrical Circuit

                                                       Diagram 1: Overall Circuit


The microcontroller is powered by a 9V battery, which supplies the voltage divider circuit with
5V. A resistor (within the range of 10K Ohms) is connected to the 5V port of the
microcontroller and the force sensor. The force sensor acts like a potentiometer—when force is
exerted on the sensing area, the resistance of the force sensor decreases. If no load is applied to
the force sensor, the resistance is greater than 5M Ohms. The resistance decreases with
increasing force. The other end of the force sensor is connected to ground, and the
microcontroller input is connected in parallel with the force sensor. Therefore, the input reading
is the varying voltage reading across the force sensor (see diagram 2, below).
       The microcontroller takes these readings and spits out a value to the throttle on the speed
controller. The speed controller then controls the motor’s speed, depending on the value from
the microcontroller.

From Diagram 2, the voltage read by Arduino is
              5  Rsense
       V 
             R1  Rsense
The voltage will be at a minimum when Rsense is at a minimum. From l'Hôpital's rule, maximum
voltage approaches 5 when Rsense approaches infinity.

Voltage Divider Circuit

                                  Diagram 2: Voltage Divider

Source Code

/* Smart Skateboard Program #4
 * Simple program that compares the total back readings with the total
 * front readings and outputs a value to the speed controller.
 * By: Neil Chen and Kristin Inouye
 * Created 28 April 2009

int a=0, b=0, c=0, d=0, e=0, f=0;
int front=0, back=0;
int spd=0;

void setup()
  pinMode(3, OUTPUT);       // declare the speedPin as an OUTPUT

void loop()
    a   =   analogRead(0);       // read the value from the force sensor 1
    b   =   analogRead(1);
    c   =   analogRead(2);
    d   =   analogRead(3);
    e   =   analogRead(4);
    f   =   analogRead(5);


    front = a+b+c;
    back = d+e+f;

    if (front > back){
      spd = front*(1.85);
    spd = 0;

    analogWrite(3, spd);



First, the program takes in the analog value from the six different force sensors (NOTE: Analog
input values range from 0 – 1023). Next, they are individually inverted to compensate for the
decreasing resistance when force is applied. The three front sensors (sensors that are located
under the front foot pad) are added up, as well as the three back sensors (sensors that are located
under the rear foot pad). These two sums are then compared; if the front sum is greater than the
back, the output to the throttle is the front sum multiplied by 1.85. If not, then the output is equal
to zero (motor is turned off).

This program is in a loop, so the values from the force sensor are constantly being read, as well
as the output is constantly changing.
Business Feasibility
Business Concept Statement

    Skateboards and long boards have been established as common and inexpensive forms of

portable transportation. With advances in battery technology over the previous decade, and

increased availability of composite material in consumer products, a new and expandable market

subset has developed for alternative (“green” and “hybrid”) modes of transportation. The new

electric skateboard industry is currently in its infancy, and there exists significant exploitable

potential within it.

    Powerboards offer the benefit of functional transportation with an added entertainment factor

not available from other items that fill the same transportation needs. They travel as fast as an

Olympic track runner with a range of up to 10 miles or more, while virtually eliminating the

learning curve otherwise associated with beginning to ride a skateboard or long board. They can

be carried indoors for storage, or easily stashed in the trunk of a car for college commuters.

These features come for a relatively affordable initial price, and minimal upkeep costs.

    SMRTboards plans to revolutionize this industry for the first time since its creation. It will

target expansive, renewable, and eager market segments that have yet to be reached by current

industry players, with state-of-the-art technology providing unique benefits that meet consumer

needs more efficiently, at a price point lower than the currently available.

    To determine the state of the industry, the scope of potential customers, distribution and

production possibilities and optimization, analyze deliverable benefits, and perform financial

feasibility analyses, data was obtained from a number of primary and secondary sources. As a

result, a series of marketable solutions will be proposed.
Industry Scope
   Is there a market? Does one currently exist? How long has it been around? What is the

status of the powerboard industry? How big is the market, and how many major players are

there? What are the current methods of delivering product benefits to consumers? Is there a

niche for a new player in the industry?

   i. Background

       The electric skateboard, known commonly as the “powerboard,” is a portable mode of

   transportation that builds on the platform of a skateboard or long-board skateboard by adding

   an electric motor fed by an onboard battery pack. The first documented powerboards were

   the result of individual home experimentation of skateboard hobbyists such as Louis

   Finkle—founder of Exkate—as early as 1993. Finkle and others sold homemade

   powerboards until 2002, when Chase Boards, LLC, Exkate’s parent company, became the

   first company to enter the industry officially. The boards featured wireless trigger-style

   remote controls, and open differential rear wheel drive. Large-scale production began in


       In 2005 under the leadership of serial entrepreneur David Lohrli, E-Glide jumped into the

   industry with a competing product, also featuring a wireless trigger-style remote control. An

   immediate legal “wrangling” ensued over the utility patent Exkate had claimed for use of

   such a remote for application with powerboards. As a result, E-Glide switched to tethered

   remote operation, as well as becoming the first industry player to move to domestic

   manufacturing, and setting the stage for a competitive market environment.

       From 2006 through 2008, a handful of new competitors entered the industry, most

   notably Thrust Powered, LLC of Silver Lake, California. However, with the exception of

   Kef Design, LLC, manufacturer of Metroboards, few entrants have made notable

   improvements or modifications to the original powerboard design. SMRTboards has the

   ability to provide those notable improvements.
ii. Major Players

Chase Boards, LLC

   Chase Boards, LLC sells the Exkate brand of powerboards under the trade mark Altered.

They are based in Lake Forest, California, and have been in business since 2002. They are

known for their established reputation as the first company to seriously break into the

powerboard industry. Key advantages they have are established brand name, Chinese

manufacturing that results in higher margins, and intellectual property regarding handheld,

wireless, trigger-style remotes for use with powerboard applications.

Crossbow USA, Inc

   Crossbow USA, Inc sells the E-Glide brand of powerboards. They are based in Santa

Monica, California, and have been in business since 2004. They are known for their

domestic manufacturing, deeper product line, and established brand name in the powerboard

industry. Key advantages include the incorporation of tethered remote operation to avoid

paying royalties to Chase Boards, LLC, and product line of models available over a wide

range of prices and capabilities.

RDX Industries, LLC

   RDX Industries, LLC manufactures and sells the Thrust Powered brand of powerboards.

They are based in Santa Ana, California, and have been in the powerboard business since

2007. They are known for their cross-pollinated offerings of both powerboard and electric e-

bike products. Their key advantages are in-house access to their own plastic rotational-

molding machinery, saving on bulk production costs, and for their thorough due diligence on

previous entrants to the powerboard industry.

Kef Design, LLC

   Kef Design, LLC manufactures and sells the Metroboard brand of powerboards. They

are based in Portland, Oregon, and have been in business since 2004. Their key advantages

are their much lighter product weight, competitive pricing, and industry-leading battery
   option selection. They are also the only notable industry player located outside of Southern


Industry Analysis

   i. Current and Future Trends

      The powerboard industry in its infancy has as much as a $10 Million per year market cap.

   The skateboard retail industry grosses $5.1 billion per year according to Board-Trac and the

   International Association of Skateboard Companies (IASC). Much of the availability and

   future potential of powerboards comes from improvements in battery technology over the

   past decade. The battery industry has sales exceeding $40 billion per year according to 2005

   estimates, and the advancements in Lithium ion cells has been crucial to the proliferation of

   cellular phones and hybrid cars.

   ii. Benefits

      The array below outlines the features comparison between a possible SMRTboard

   product offering and its primary initial competition:
Feature                 Exkate       E-Glide       MetroBoard    ThrustPoweredSMRTboard

Entry Price                 $600         $630          $499          $579           $499

Weight (lb)                  45           51           18-22         35-45         25-35
                                                                                SLA, NiMH, or
Battery Options           SLA only     SLA only    SLA or NiMH    SLA or LiPo       LiPo

NiMH Battery Price          NA            NA           $695           NA            $599

LiPo BatteryPrice           NA            NA           $795         $1,076          $699

Power                       600           400           450           600           350

Top Speed                    19           20            16            18            15
                                                                                 Regen and
Braking                    Regen        Regen         Regen         Regen          Drum

Hands-Free Operation?        No           No            No            No            Yes

Range                        10           12        12            10                  8
                        105mm Hard   105mm Hard              105mm Hard          97mm Soft
Wheels                    Urethane     Urethane 84mm Urethan   Urethane           Urethane

Made In                    China         USA           USA           USA            USA

Key Lock?                    No           No            No            No            Yes

Truck Width                220mm        220mm         180mm         220mm          250mm

   The SMRTboards line of products offers superior features and benefits over the

competition at a lower retail price. It offers the lightest weight of any full-sized powerboard,

allowing more portability and better efficiency. With more battery pack options than any

other manufacturer, SMRTboards have a lower entry price and choices for multiple budgets.

The smaller, 24 volt motor uses less energy to accelerate, and reaches a similar top speed.

The one-way bearing on the chain drive allows the SMRTboard to be the only powerboard

that can be ridden if the battery runs out. A total of 86.6% of survey respondents desired a

powerboard with a range of 8 miles or less, and the SMRTboard meets that need without

unnecessary battery weight.

   SMRTboards also have a few unique features. They have the widest wheelbase of any

powerboard, for the best available turning stability. Their pneumatic drive wheel and the

largest low-durometer urethane front wheels available combine for a significantly smoother

ride on rough pavement. SMRTboards’ most prominent feature is the pressure-sensitive
   deck, which eliminates the need for a remote control, dramatically shortens the learning

   curve for new riders, and improves safety. Not only will riders not face the danger of

   tripping on a tethered remote wire, but will free up the use of the rider’s other hand for

   balance, carving around turns, or holding a cup of coffee on the way to class.

Customer Scope
   Who are current customers of the powerboard industry? What needs do they have for, and

what pains can by solved by powerboards? What potential target customers would benefit most

from powerboards? What do customers want out of powerboards to find value in them?

   i. Current Customers

       The majority of current customers are adult males between the ages of 30 and 45,

   comprising between 60% and 80% of all end consumers of powerboards. There is currently

   no recognizable wholesale distribution market.

Customer Analysis

   i. Primary Customers

       Primary customer at launch will be college student consumers, primarily male, between the

   ages of 18 and 23. This target market has a clear and present pain of short range transportation

   that is currently being filled by skateboards, bicycles, and scooters, or not at all. This market of

   potential consumers is large compared to current powerboard industry sales, with 18 Million

   individuals attending college in the United States in 2007 according to the NCES Digest of

   Educational Statistics, with 5 Million new students entering college each year, renewing annually

   to provide a continued stream of new potential customers within the same market segment.

   Parents of current and incoming college students are also a primary customer, and with their

   greater buying power, will be targeted as much as the students themselves.
   All other direct-to-consumer consumers will be primary customers as well. Established

adult males between the ages of 30 and 45 will continue to patronize the powerboard

industry. Primary interview data demonstrated a tendency for hobbyists of various board

sports such as snowboarding, wakeboarding, and surfing, to be interested in purchasing a

powerboard as well. Regular participation in these board sports often requires the purchase

of a board and accessories that exceed the target retail price point for entry model


iii. Secondary Customers

   Future plans for SMRTboards will target bulk customers, selling in quantity and licensing

rights to the hands-free operational technology. One category of tertiary customers includes

quantity sale to skateboard and sporting goods shops in a variety of settings. Shops in beach

cities, college communities, and tourist destinations will be used to enter into the skateboard

and sporting goods market segment. For some applications, SMRTboards will be distributed

both for consumer sale and rental.

   The other category of secondary customers will license SMRTboards technology. The

technology will be adapted and licensed to direct competitors in the powerboard market;

much in the same way that several industry players license the wireless trigger-style remote

operation from Chase Boards, they will license the hands-free board operation technological

capabilities from SMRTboards. Similarly, Big 5 Sporting Goods, Sports Chalet, Toys R Us,

REI, and other large retailers will be targeted for licensing the production of private label

store brand powerboards with hands-free operation.
    Financial Scope
       i. Industry Financials

             Some financial information was obtained through primary interviews, and through

        available online databases, and is displayed below where applicable for retail price of most

        popular model powerboard, approximate margin per unit, total sales volume, and

        approximate annual revenue and annual costs:

                   Chase Boards, LLC    Crossbow USC, Inc     RDX Industries, LLC     Kef Design, LLC
  Retail Price            $599                  $629                  $579                  $499
    Margin                 NA                   NA                    40%                    NA
  Sales (units)            NA             4000 (since 2004)       25 (per month)          55 (2008)
Revenue (approx)        $750,000              $750,000                 NA                    NA
 Costs (approx)         $283,000              $238,500                 NA                    NA

    Financial Analysis

        i. Price Margin

             At a late stage in the product design process, fairly accurate numbers can be accumulated

        to estimate the actual cost of production of each powerboard unit. A pricing breakdown for

        the entry model SMRTboard follows as:

      Costs to produce (SLA)                                              Est. Price/Unit (Bulk)
       Category            Item                                Quantity   Item Price      Total
       Sensors             Flexiforce Force Sensor (100lb)            2       $16.75       $33.50
       Computer            Proprietary Circuit Board                  1       $15.00       $15.00
                           Drive Wheel (Razor E300)                   1       $17.99       $17.99
       Wheels              250mm Truck                                1       $22.00       $22.00
                           97mm-76a Wheels + Bearings                 1       $29.83       $29.83
                           250-500W 24V Speed Controller              1       $32.99       $32.99
                           350W 24V Motor                             1       $26.99       $26.99
                           24V 1.5A Charger                           1       $21.56       $21.56
                           SLA Battery 12V 7.5Ah (24V tot)            2       $20.66       $41.32
                           Chassis (est.)                             1       $40.00       $40.00
       Parts               #25 Chain (per ft)                         3        $2.50        $7.50
                           Keyswitch                                  1        $2.49        $2.49
       Subtotal                                                                           $291.17

        From that, the price margin analysis at the target retail price of $499, with totals from the

        NiMH and LiPo optional models, follows as:
 Total Price/Margin                             SLA       NiMH      LiPO
Total Production Cost Per Unit                    $321.17 $425.25 $518.28
Target Retail Price                               $499.00 $599.00 $699.00
Net Profit Per Unit                               $177.83 $173.75 $180.72
Percent Margin Per Unit                           35.64%    29.01%     25.85%
Monthly Expenses (est)                          $5,000.00 $5,000.00 $5,000.00
Units Sold Per Month to Break Even (P&L)            28.12     28.78      27.67

Margins land between approximately 30% and 36%, which falls in line with the estimated

40% margins of RDX Industries’ ThrustPowered powerboards, but with an overall lower

price point.
Our board is electrically powered by a motor and controlled on how a person shifts his/her
weight on the board. For our design, we recognized that it is potentially dangerous due to speed
and maneuvering. So, we created a program that had a maximum speed limit (15mph), a good
speed that compromises safety and fun. Also, our program allowed the rider to gradually
accelerate (depending on how much the person leaned), preventing the rider from falling off.
Our board was designed to compliment the natural movement of humans. When the rider leans
forward, the board accelerates; when he/she leans back, the board decelerates. By physics, it is
best for the rider to lean forward when accelerating, and back, when decelerating. Thus, the ride
is much smoother and stable. We also engineered the board to have a low profile to the ground
and wide trucks for greater stability. Although we had to forfeit a tight turning radius, we gained
durability. In the end, we created a balance between fun and safety. Riders can have an
awesome time skating, and not fearing for their life.
       Still, several adjustments would have to be made to this prototype before it could be
distributed commercially but even then we would recommend a helmet. Even after safety
features such as a brake, grip tape, and more precise speed control were incorporated a helmet
would still be recommended.

At the beginning of this semsester we set out to build the first ever hands free electric skateboard
and we achieved just that. The board can be competently ridden around school in a safe yet
extremely fun manner. It is truly a rush to ride as it feels like an extension of oneself.
       There were three keys to our success. The first was starting early. We began the
brainstorming process right at the beginning of the semester and continued to meet once a week
for the duration of the project. The second key was good communication as we constantly shot
back and forth phone calls, emails, and text messages in order to inform each other of progress.
The third key was finding good mentors. Both Rand in the robotics lab and Ewald in the
fabrication lab provided us valuable advice.

Thank Yous
Rand Voorhies for advising us on microcontrollers and programming concepts and Ewold from
the Undergraduate Fabrication Lab for helping us turn our vision into a reality.
Appendix: Additional Pictures 

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