Requirements Specification Document

Dash Electric Longboard Requirements Specification
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Dash Electric Longboard
System Requirements Specification
Version 1.0
[12/2/15]

Table of Contents
1. EXECUTIVE SUMMARY ............................................................................................................................................... 3
1.1 PROJECT OVERVIEW .......................................................................................................................................................... 3
1.2 PURPOSE AND SCOPE OF THIS SPECIFICATION ......................................................................................................................... 3
2. PRODUCT/SERVICE DESCRIPTION ............................................................................................................................... 3
2.1 PRODUCT CONTEXT ........................................................................................................................................................... 3
2.2 USER CHARACTERISTICS ..................................................................................................................................................... 3
2.3 ASSUMPTIONS ................................................................................................................................................................. 4
2.4 CONSTRAINTS .................................................................................................................................................................. 4
2.5 DEPENDENCIES ................................................................................................................................................................. 4
3. REQUIREMENTS ......................................................................................................................................................... 4
3.1 FUNCTIONAL REQUIREMENTS .............................................................................................................................................. 5
3.2 USER INTERFACE REQUIREMENTS ......................................................................................................................................... 6
3.3 USABILITY ....................................................................................................................................................................... 7
3.4 PERFORMANCE .................................................................................................................. ERROR! BOOKMARK NOT DEFINED.
3.4.1 Capacity ............................................................................................................................................................... 7
3.4.2 Latency ................................................................................................................................................................. 7
3.4.3 Maintenance ........................................................................................................................................................ 7
3.5 SYSTEM INTERFACE/INTEGRATION ....................................................................................................................................... 7
3.5.1 Network and Hardware Interfaces ...................................................................................................................... 7
3.5.2 Systems Interfaces ............................................................................................................................................... 8
3.6 SECURITY ........................................................................................................................................................................ 8
3.6.1 Protection ............................................................................................................................................................ 8
3.7 STANDARDS COMPLIANCE .................................................................................................................................................. 8
4. REQUIREMENTS CONFIRMATION/STAKEHOLDER SIGN-OFF ....................................................................................... 8
APPENDIX .......................................................................................................................................................................... 9
APPENDIX A. DEFINITIONS, ACRONYMS, AND ABBREVIATIONS ......................................................................................................... 9
APPENDIX B. REFERENCES ........................................................................................................................................................ 9
APPENDIX C. REQUIREMENTS TRACEABILITY MATRIX ..................................................................................................................... 9

1. Executive Summary
1.1 Project Overview
Dash Electric Inc. is developing an electric longboard kit that can be attached to most longboards on
the market without any power tools or screws needed. It uses hub motors that attach to the existing
longboard trucks and a novel electronics package that contains the batteries and all electronics needed
to run the motors. The electronics package is on a unified board that mounts between the deck and the
trucks using the 4 holes used for mounting the trucks that are standard on every longboard and
skateboard. This ease of mounting also minimizes assembly and manufacturing costs because no
modifications need to be made to any components of the longboard for attaching the electronics and
motors to.
1.2 Purpose and Scope of this Specification
In scope
This document addresses requirements related to Phase 1 of the longboard development:
• Bluetooth controlled electric longboard
Out of Scope
The following items in phase 3 of the longboard are out of scope:
• Firmware updates over Bluetooth.
(Phase 3 will be considered in the development of the requirements for Phase 2, but the Phase 2
requirements will be documented separately.)
2. Product/Service Description
The Dash Electric Longboard is an electric skateboard that is light enough for urban commuters to carry
with them anywhere they go but is powerful enough to take them around the city for getting to work or
running errands around town.
2.1 Product Context
This product is manufactured as a kit but is designed to easily interface with most longboards on the
market. The kit is sandwiched between the longboard deck and the truck base plate. Our motor is
designed into one or two wheels(depending on configuration) and is easily attached by screwing it onto
the existing axle. The longboard is controlled by a wireless remote.
2.2 User Characteristics
• College Student That Already Longboards
o Ride to and from class and around campus.
o 18-24 years old
o Has a longboard
o Knows how to ride a longboard
• College Student New to Longboarding
o Ride to and from class and around campus.
o 18-24 years old
o Does not have a longboard
o Dos not know how to ride a longboard

• Urban Commuter
o Ride to and from work and around town for errands
o 18+ years old
o Lives in a city
o Travels on public transportation and uses taxis
o Never ridden longboard or minimal experience
2.3 Assumptions
None
2.4 Constraints
• Must fit onto longboard/skateboard standard 4 hole mounting pattern
• Wheels must fit onto standard 8mm axle shaft
• access, management and security
2.5 Dependencies
• This product will require recharging the battery pack after it has been depleted.
3. Requirements
• Power
o Off: Battery pack is powered off, no light illuminated on pack
o On: Battery pack is powered on, on light illuminated on pack
o Charging: Battery pack is powered off, charge light is illuminated
• Riding Modes
o Beginner Mode: Acceleration limited to 20%, top speed limited to 8mph
o Eco Mode: Acceleration limited to 40%, top speed limited to 15mph
o Commuter Mode: Acceleration limited to 80%, top speed unlimited
o Power Mode: Acceleration unlimited, top speed unlimited
• Controller
o BLE transceiver
o Joystick for acceleration/braking
o Button for cruise control
o Button for reversing direction
o Power button for On/Off
o Switch for riding mode selection
o 3.7V 18650 li-ion battery
o Casing for electronics and controls
o LEDs for On/Off, Ride Modes
o Button for “dead man’s switch”
• Battery Pack
o 37V Li-ion pack arranged 10cells in series, 2 in parallel(10S2P)
o 40A max continuous current limited by BMS
o Max burst current 200A(<5sec)
o Max Charge Voltage: 42V
o Min. Operating Voltage: BMS regulated 3.0V
o 2”x1” LED Voltage Display
o LED backlit On/Off button
o 37V 40A BMS board
o Plastic Enclosure
• Speed Controller(ESC)

o V4.10 or higher VESC Speed controller
o FOC(Field Oriented Control)
o 50A continuous capability
o 48V Max Voltage
o JST Input for firmware updates
o CAN Bus for multiple ESC communication and traction control
o Mounted to 3”x7” aluminum plate for heat syncing
o PWM leads for BLE transceiver
• Hub Motor
o Wye wound copper windings
o Lacquer coat windings
o 150 C rated curved neodymium magnets
o Nylon thread locking
o 8mm threaded shaft for mounting to axle
o 50mm OD motor casing with
o 75mm OD urethane sleeve, 50mm ID
o 3 lead PWM direct from windings out of stator
• BLE Transceiver
o 3.3V BLE transceiver
o PWM leads for ESC
• LED Road Lights
o White forward facing LEDs
o Red rear facing LEDs
o Power On/Off switch
• Charger
o 3 pin male cannon style connector for power ouput
o 42V max charge
o 5A charge rate
o Stop charging when max voltage reached
o LED indicating charging/not charging(red is charging, green is charged, no light is off)
o US 110V AC male plug for power input
Priority Definitions
The following definitions are intended as a guideline to prioritize requirements.
• Priority 1 – The requirement is a “must have” as outlined by policy/law
• Priority 2 – The requirement is needed for improved processing, and the fulfillment of the
requirement will create immediate benefits
• Priority 3 – The requirement is a “nice to have” which may include new functionality
3.1 Functional Requirements
Req# Requirement Comments Priority
Date
Rvwd
SME
Reviewed /
Approved
BR_01 The system should let the
user know when it has been
powered on.
LED indicates on through
steady green. Remains on
as long as battery pack is on
1

Req# Requirement Comments Priority
Date
Rvwd
SME
Reviewed /
Approved
powered off.
LED indicates off through no
ilumination. LED remains off
as long as battery pack is off
1
user know when it is
charging.
Charger indicates charging
through red LED illuminating
1
user know when it is charged.
Charger indicates charged
through green LED
illuminating
1
BR_05 Controller should let user
change the ride mode.
4 position switch to select
ride mode
2
4 position switch to select
ride mode
2
BR_07 User should have road
lighting front and rear(toggle
on/off)
Nice to have but not
absolutely necessary
3
BR_08 User should be able to update
firmware
Firmware updates over BLE 3
BR_09 User should be able to charge
wireless controller with Dash
battery pack
Charger/mount integrated
into electronics casing
2
BR_10 User should be able to
accelerate with forward on
joystick
1
engage regenerative braking
with backward on joystick
1
engage cruise control with
button on controller
2
BR_12 System should not allow input
for acceleration or breaking
unless dead man’s switch
engaged
Momentary dead man’s
switch on wireless controller
2
BR_13 Wireless controller should
indicate power level
Upon powering on flashes
red 3 times for full, 2 times
for half charge, rapid 10
flashes for needing charging
2
BR_14 Controller to board BLE
connection should be
encrypted
3
3.2 User Interface Requirements
• If bluetooth controller is not paired with a longboard the power light with flash for .5 seconds
every 1 seconds for 30 seconds then controller will power off.

• If bluetooth controller is paired with a longboard the power light should remain constant red as
long as controller is powered on.
• When longboard is turned on a LED will illuminate the button and stay illuminated until
longboard is turned off.
3.3 Usability
• A user who has never ridden a longboard before should be able to ride the longboard in a straight
line for 50 feet after 10minutes of practice in beginner mode
• The longboard should be able to regenerative brake down to 1mph with a 220lb or less rider.
• The longboard should be able to accelerate up to 20mph with a 220lb or less rider.
• The system electronics should be fully powered on or off within 2 seconds of power button being
pressed.
3.4 Performance
3.4.1 Capacity
• Battery pack should charge between 41-42V for a minimum of 200 times before degrading below
41V.
• On flat ground the battery pack should last 10 miles on flat pavement with consistent throttle input
and a rider weighing 220lbs or less.
3.4.2 Latency
Latency between wireless controller and board should be 200ms or less at a distance of 4ft or less.
3.4.3 Maintenance
• User must charge the battery pack after pack indicates it is depleted.
• User must replace hub motor wheel sleeves when worn down to less than 55mm OD.
• User must charge wireless controller when indicating that it is depleted.
3.4.4 Operations
• User should always wear a helmet when riding
3.5 System Interface/Integration
3.5.1 Network and Hardware Interfaces
• User should always wear a helmet when riding

3.5.2 Systems Interfaces
A. Wireless controller to on board’s transceiver Interface
The user will input a command through a joystick or button on the controller. This is sent over BLE to the
transceiver on the board. The transceiver receives the data and outputs the numerical value received as
a pwm signal to the ESC.
B. ESC to motor Interface
When the ESC receives a pwm command from the transceiver it takes in the BEMF from the motor to
determine its position and inputs power timed to the motor’s current speed that corresponds with the input
received from the transceiver.
3.6 Security
• On power up wireless controller and on board transceiver establish an encrypted connection.
3.6.1 Protection
• encryption
• restrictions on inter-module communications
3.7 Standards Compliance
• Electronics board is IP64 compliant
4. Requirements Confirmation/Stakeholder sign-off
Meeting Date Attendees (name and role) Comments
TBD
TBD

APPENDIX
Appendix A. Definitions, Acronyms, and Abbreviations
• ESC: Electronic speed controller
• BLE: Bluetooth Low Energy
• Li-Ion: Lithium Ion Battery
• PWM: Pulse Width Modulation, a modulation technique used to encode a message into a
pulsing signal.
Appendix B. References
• Dash Electric Concept of Operations Document
Appendix C. Requirements Traceability Matrix
Req# Requirement Deliverable Name Priority Status
powered on.
1
powered off.
1
user know when it is
charging.
1
user know when it is charged.
1
2
2
BR_07 User should have road
lighting front and rear(toggle
on/off)
3
BR_08 User should be able to update
firmware
3
BR_09 User should be able to charge
wireless controller with Dash
battery pack
2
accelerate with forward on
joystick
1
engage regenerative braking
with backward on joystick
1

Req# Requirement Deliverable Name Priority Status
engage cruise control with
button on controller
2
BR_12 System should not allow input
for acceleration or breaking
unless dead man’s switch
engaged
2
BR_13 Wireless controller should
indicate power level
2
BR_14 Controller to board BLE
connection should be
encrypted
3

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