Transcript CDR - UCF EECS

Liz Lyons
Mike Scherban
Oscar Orihuela
What Is Knightro Kart?
An interactive, Android
controlled vehicle race system
consisting of two independent
cars and controllers.
 Vehicles are controlled by
Android powered mobile
devices or tablets
 Consists of two
independent vehicles, a
track utilizing infrared, and
two independent remote
controls
System Block Diagram
System Specifications
Bluetooth Communication Range
<30 m
Vehicle Speed
20 MPH max
Battery Life
>1 hr
Number of Users
2
Remote Control
Mobile device will be used in landscape mode. It will
utilize hardware level sensor data, and interpret them to
tell the MSP430 how to direct the vehicle.
Why Android?
 Essentially Free – No new hardware costs,
free SDK, familiar languages
 Open source platform, easy to learn
Programming
Language
Devices
Readily
Available?
Familiarity
Cost to
Develop
Android
Java/XML
Yes
High
Free
iOS
Objective-C
No
Medium
$99/year
Windows
Phone
.NET
framework/
Visual
C++/XNA
No
Low
Free
Target APIs 10 (Android 2.3.3 Gingerbread and higher),
approximately 88.2% of Android market
Target APIs 10 (Android 2.3.3 Gingerbread and higher),
approximately 88.2% of Android market
Remote Control Requirements
Android Device Must:
 Have Bluetooth Capability
 Contain Accelerometer Sensors
 Have Touch Screen
 Run Android 2.3.3 Gingerbread or newer OS
Handling Accelerometers
Accelerometers are seen by
the devices relative to an
imagined coordinate system.
 We will be using the Y
(left/right) and Z
(forward/back) axis values
to control the cars.
Handling Accelerometers
Must apply low-pass filter to isolate gravity, and then a high-pass filter to
remove gravity from the readings. Also helps to smooth out values.
Wireless Communication Choices
Bluetooth
(Class 2)
Wi-Fi Direct
Wi-Fi
(traditional)
Protocol
LMP, L2CAP, SDP
IEEE 802.11 a/g/n
IEEE 802.11
Communication
Distance
Radio dependent,
≈ 10 meters min
200 meters MAX
200 meters MAX
Speed
3 Mbps MAX
250 Mbps MAX
250 Mbps MAX
API Requirement
5 or higher
14 or higher
1 or higher
Power
2.5 mW
Varies
Varies, may be 40x
Bluetooth
ISM Band
2.4 to 2.485 GHz
2.4 GHz or 5 GHz
2.4 GHz or 5 GHz
Difficulty
Low
High
High
Connecting
Android devices will be able to connect to one and only
one car.
 Will use received values from the MSP430 to enhance UI with more
info such as vehicle speed and current lap.
Bluetooth
Remote control application sends information to the MSP
430 via Bluetooth.
 Sends one byte at a time, byte value depends on
accelerometer values
Ascii Value
Direction
Accelerometer
Values
Y
Forward
Z > 1.5
R
Back
Z<0
Bluetooth Module
 Roving Networks RN-41
 Minimal configuration

Baud rate
 Built in antenna
 Automatically pushes data via UART RX/TX pins
 Runs own Bluetooth stack
 Low power
 30 mA connected
 3.3V
 100m range
Microcontroller
MSP430G2553
Atmega168 w/ Arduino
3.3V
5V
16KB flash
16KB flash
C, Assembly
C, Assembly
16MHz
16MHz
UART & PWM support
UART & PWM support
2.75”
2.75”
Microcontroller
MSP430G2553
3.3V
16KB flash
C, Assembly
16MHz
UART & PWM support
• Same voltage as Bluetooth module
• More feature rich IDE
• No special bootloaders required
Microcontroller
MSP430G2553 (28 pin TSSOP)
Surface mount package
Function
# of Pins
UART
2
Infrared
1
LEDs
5
Motors
4
Misc.
2
Programming and Debugging
 JTAG used to take advantage of viewable registers and
memory locations, and disassembly
 Connect through TI USB FET device
Motor Signals
 Takes advantage of MSP430 hardware PWM support
 PWM used to add variable speed
Slow
Fast!
Microcontroller Comm.
 9600 Baudrate
 RX/TX between BT and MSP430 crossed
 Interrupts will be used for phone  MSP430 and
infrared signal
Low Power Mode
 Bluetooth Module separate from MSP430
 Allows BT pairing while MSP430 is asleep
 MSP430 goes to sleep at power on and when not in
race mode
 Turns off clocks
 Button on the car or command from phone will wake
the car for use
MSP430 Software Flowchart
Printed Circuit Board
 Most components will be on a custom printed circuit
board designed in Eagle
Printed Circuit Board
BT Module
and status
LEDs
LEDs
JTAG
Power
MSP430
Track
 Race car will contain an IR phototransistor
 Biased by IR light
 At the START line for the Race Track, there will be a
line of IR LEDs that will set off IR phototransistor
 By setting off the IR phototransistor on the car, it will
allow user to know how many laps the car has travelled
during the race
Race Car
 9v power supply







required
Potential to travel
20 mph
2 D.C motors
1st Motor controlling
FWD & REV motion
2nd Motor controlling turning Left & Right
17 inches Long
7 inches Wide
8 Inches Tall
H-Bridge
 Serves as mediator between MSP430 & Race car
motors
 MSP430 will receive commands from Mobile
Application and send high / low signals to the Hbridge connected to the motors causing the motors to
spin in a certain direction
 EX: Clockwise / Counter-clockwise / Stand Still
H-Bridge - Typical
 Typical H-Bridge configuration
 Inner Circle = Motor
 Switches represent Transistors
 Motor is at a stand still
H-Bridge - Clockwise
 Due to the directional flow
of the circuit, the H-bridge
is causing the D.C Motor
connected to it to spin
clockwise
H-Bridge – counter clockwise
 Due to the directional flow
of the circuit, the H-bridge
is causing the D.C Motor
connected to it to spin
counter-clockwise
SN754410
 H-Bridge Designed to drive inductive






loads such as DC Motors
Chosen for its capability to manage
both D.C Motors in a single chip
Manufacturer: Texas Instruments
Cost: $2.16
1 Chip per car needed
.
.
SN754410 Layout
D.C Motor VS Servo Motor
 Race car will require 2 motors
 1st Motor controls – FWD & REV motion – D.C Motor
 2nd Motor Controls – turning capabilities
D.C Motor
Servo Motor
Less Expensive
More Expensive
Requires Less Voltage
to function
Requires Higher
Voltage to function
Slower Reaction Time
Faster Reaction Time
 For the purpose of Knightro Kart, D.C motors will be
sufficient as well as better for our wallets & Handbag
Power Supply
Power
Supply
Voltage
Regulator
SN754410
9V
5V
Race Car
9V
Does Not
Require
MSP430
9V
3.3V
Desirables
 Speedometer
 Phone to Phone Communication
 Race Standing Notifications
Speedometer (optional)
Magnetic Reed Switch
 Switch opens at close proximity
of a magnet
 Sends PWM signal back to
MSP430
 Switch will be attached to axel
of Race car
 Low power magnet will be attached to rim or inner
wheel of the race car
Budget and Financing to Date
Batteries, $10.00
JTAG
Programmer,
$100.00
Linear Regulators,
$1.00
Passive
Comonents,
$50.00
RC Vehicles,
$80.00
Bluetooth Modules,
$25.00
H-Bridge Chip, $5.00
Photo
IR Lights, $5.00
Transistors,
Infrared
$2.00
Sensors, MSP430s,
$0.60
$6.00
Total Cost To Date:
$364.60
PCBs, $80.00
Remote Control, $-
Current Progress
Android Code
MSP430 Code
Construction
Completed
Remaining
Research
Purchasing
0%
20%
40%
60%
80%
100%
Plans For Completion
 Complete Soldering
 Complete Code
 Assemble Vehicles
 Test
 Construct IR Start Line