Group #2
Jorge Avilla
Luis Bonilla
Redwood
 Diego Nunez



Project Purpose:
Project Overview

Create a robot that is able to collect
tennis balls either autonomously or
manually.
Goals and Objectives
To autonomously or manually pick up
tennis balls.
 Recognize objects using a vision system.
 Able to keep track of number of balls
collected.
 Wireless control from a remote control if
it’s not on autonomous mode.

Specifications & Requirements
Robot cost around $700.00.
 Weight less than 7 lbs.
 Ability to carry 3-5 tennis balls.
 Range of 120 ft.
 Battery life of around 1 hour.

Project Components

Vision System: To identify objects

DC Motors: For movements of the robot

Batteries: To provide power to all
components of the robot to function
properly

Ball Collecting Mechanism: To collect the
tennis balls

Wireless Device: To manually operate the
robot
Chassis Design
Custom Chassis
 Modeled in SolidWorks
 Built the actual chassis
using clear acrylic sheets
 Connect the robot’s
platform using L-brackets

Ball Collecting Mechanism
Paddle Wheel design.
 Built with PVC and clear
acrylic sheet.
 The system uses a DC
motor to rotate the paddle
in order to collect the balls.

Chassis Design
Ball Counter
ABC uses 2 Sharp IR Range Sensors.
 Each sensor eliminates the 10 cm
minimum distance of the other.
 The sensors are located inside the chassis,
behind the wheel paddle.

Drive Train
Motors
2 DC motors for movement
 Operating Voltage = 12 volt
 Operating Current = 90 mA
 Stall Current = 1.5 A
 Stall Torque = 123.20 oz.-in
 RPM = 120
 Weight = 5.36 oz.
 Price = 21.95 each

Wheels

Rear Wheels
◦ 2 All Terrain Wheels

Front Wheels
◦ 2 Caster Wheel
to provide balance
Visual System
Blackfin Camera:
•
•
•
•
Color Detection
Motion Detection
Compatible with WebBot Library
It communicates via UART
Specifications
Processor
Processor’s Speed
Input Voltage
Current Draw (max)
UART
Number of Timers
Frames per Second
I/O pins
Resolution
Blackfin Camera
Blackfin BF537
500 MHz
3.3 V
145 mA
2
4
30
16
640x480
Microcontroller
Atmega328
Specs
Pins
I/O pins
EEProm
Program Memory
SPI
USART
Timers 8/16 bit
PWM pins
ADC channels
Programming Language
Max Clock Rate
Voltage
Price
Atmega328
32
23
1K
32K
Yes
1
2/1
6
8
C
20 MHz
1.8-5.5V
$5
Microcontroller
Why atmega328:
• More Programmable Memory
• Previous experience with atmega8 and atmega168
• Already had programmer available.
• WebBot Library: Functions library compatible with the
328 and with the Blackfin Camera
• Simplifies programming process.
Microcontroller Design
3 Microcontrollers:
• Simplifies testing of the different parts separately
• Allows for the coding to be divided among the group
Main Controller:
Brain of the robot, receiving and transmitting information between the
other two microcontrollers and the camera
Motor Controller:
Receives input from the main controller or the laptop(RC mode).
Controls the input of the h-bridges.
XBee
Blackfin Camera
Main Controller
Motor Controller
L298N
Counter
Counter:
Keeps count of the number of
balls the have been loaded on the
vehicle and instructs the Main to return
to the base once the goal has been
reached.
Main Controller and Counter Schematic
Motor Controller modes:
• Autonomous mode: Receives its input from the main controller
Controlling Truth Table:
Pins Main Controller/Motor Controller
C3/C3
C4/C4
C5/C5
Action
0
0
0
Stop
0
0
1
Forward
0
1
0
Reverse
0
1
1
Turn Right
1
0
0
Turn Left
1
0
1
Roller on Forward
1
1
0
Roller on Reverse
1
1
1
Roller OFF
Motor Controller Modes:
• Remote Control Mode: Receives its inputs from a Laptop via XBee.
Xbee Receiver
Laptop
Motor Controller
Xbee Emitter
H-Bridge:
• Receives the input from the motor controller and provides the power
to the DC motors.
• Protects the microcontroller from any shorts from the motors.
L298 from STMicroelectronics Characteristics:
Specs
L298
Logic Supply Voltage
5V
Voltage Supply (motors)
Up to 45V
DC Current Supply per Channel
2A
# Channels
2
PWM Capable Pins
Yes
Logical 0 Input Voltage
Up to 1.5 V
L298 Configuration Schematic:
• Diodes are fast response Schottky diodes.
Motor Controller with L298s Schematic:
Wireless Adapters
vs.
Specs
Range
Voltage
Current TX
Current RX
Idle current
Frequency
Interface
Price
Xbee
300ft
3.3V
45mA
50mA
<10uA
2.4GHz
TTL
$19
BlueSmirf
350ft
4.5-5.5V
Up to 120mA
40mA
2mA
2.4GHz
TTL
$64
NiMH Rechargeable Batteries

12V Battery
◦ To power all the DC motors such as the drive
train and the ball collecting mechanism

9.6V Battery
◦ To power all the electronic components such
as the camera, the sensors, and the wireless
devices for the remote control
Power Management
Power Distribution
Component
Quantity
Voltage
Max
Current
Drive Train motors
2
12 V
1.5 A
Ball Collecting Mechanism
motor
1
12 V
1A
Camera
1
3.3 V
150 mA
Sensors
3
5V
5 mA
Wireless devices for
Remote Control
1
3.3 V
50 mA
Microcontrollers: ATMEGA
328
3
5V
80mA
H-Bridge: L298
2
5V
50mA
Collision Avoidance
• The Maxbotix LV-EZ1
ultrasonic rangefinder
provides accurate
readings from a minimum
tested distance of 6 in. to
a maximum of 255 in.,
according to Sparkfun
Electronics.
• The robot is designed such that it registers any
object sensed 1 ft. away as a possible collision, and
performs a evasive procedure.
• The single rangefinder mounted on the chassis is
not enough to provide full collision detection.
Software Design
Programming Environment:
• AVR Studio 4
• AVR Pocket Programmer
Pros: Provides power to the microcontroller.
• Pololu USB AVR Programmer
Pros: Integrates directly to AVR Studio 4, allowing direct programming.
• WebBot Library
o http://webbot.org.uk/iPoint/ipoint
“This site contains useful software utilities for both the amateur and professional
robot builder. Whilst this software is Open Source I would hope, if it has been
useful, that you will visit the download page and click on the Donate button on
the top right of the page and give what you can.”
abcr_core.h
Includes
sys/atmega328P.h
switch.h
Definitions
Enumerations
operation_mode
Structures
none
Global Variables
opSwitch
Functions
appControl
appRCControl
appAUTOControl
retrieveOperationMode
• sys/atmega328P.h
Systems file from the WebBot
Library which configures the
targets the functionalities of the
Atmel Atmega 328.
• operation_mode
RC – Remote Control.
AUTO – Autonomous.
• Enable the program to be easily
switched between the two
different types of operation
modes we want to handle.
event.h
Includes
none
Definitions
none
Enumerations
event_mode
Structures
event_type
event_map
Global Variables
none
Functions
twoPowerOf
appConfigureEvents
transmitEventCode
transmitEventRef
transmitEventName
receiveEventCode
receiveEventName
receiveEventRef
• event_type
Represents an event that can be
sent or
received between
microprocessors.
• event_map
Structure that represents an
interaction that
will occur between
microprocessors.
• Intended for structuring the
interactions
that will be performed between
microcontrollers.
Acquisition.( h | c )
Includes
abcr_core.h
a2d.h
event.h
Sleep.h
Sensors/Distance/Maxbotix/EZ1.h
Definitions
IR_LEFT
IR_RIGHT
PERCENT_ERROR_DETECTION_THRESHOLD
COUNTTHRESHOLD
HOMEBASETHRESHOLD
FREQUENCY
Enumerations
Structures
Global Variables
_IREventMap
__prevIRLeftDistance
__prevIRRightDistance
_totalCount
_irSensing
mDistanceSensor
_ballAcquiredDelay
Functions
isBallAcquired
appConfigureEvents
appRCControl
appInitHardware
appInitSoftware
appAUTOControl
CollisionDetected
• Implements the sensing
and counting of tennis
balls as well as
informing the
autonomous code of a
full tennis ball storage
compartment.
• At each iteration of the
main loop, we call the
isBallAcquired function
and determine the
message to send to the
autonomous controller
from the result.
Command
vbc
Response
##vbc dd\r\n ssss x1 x2 y1 y2\r\n
....
###vcc\r\n
##vmean yy uu vv\r\n
Description
The 'vb' command searches
for blobs matching the
colors in color bin #c,
indicates the number of
blobs found as dd, and
returns a count of matching
pixels in the blob, along
with coordinates of an x1,
x2, y1, y2 rectangular
region containing the
matching pixels. up to 16
blobs can be returned, and
the blobs are sent in order
of pixel count, though blobs
smaller than
MIN_BLOB_SIZE
(currently set to 5 pixels)
aren't shown.
The 'vc' command directly
sets the contents of color bin
#c.
this command will return
string with 'vc' followed by
the color bin number. For
example, we could save a set
of colors to color bin #3
corresponding to
measurements taken at
another time, such as the
above mentioned orange golf
ball color measurement, using
'vc3127176086111154200'.
We could then confirm that
the colors were properly
stored by issuing the
command 'vr3' to retrieve the
contents of color bin #3.
Computes mean
values for Y, U, and V
over the entire image.
vccy1y2u1u2v1v2
vm
Autonomous.( h | c )
Includes
buffer.h
abcr_core.h
Cameras/Surveyor/blackfin.h
event.h
Sleep.h
Definitions
UART_RX_BUFFER_SIZE
UART_TX_BUFFER_SIZE
BLACKFIN_RESOLUTION_DEFAULT
BLACKFIN_TENNIS_BALL_BIN_RANGE
BLACKFIN_HOME_BASE_BINS_RANGE
BLACKFIN_RESOLUTION_CENTER_WIDTH
BLACKFIN_RESOLUTION_CENTER_HEIGHT
OBJECT_CENTERED_WIDTH_RANGE_ERROR_NEAR
OBJECT_CENTERED_WIDTH_RANGE_ERROR_FAR
OBJECT_CENTERED_HEIGHT_RANGE_ERROR
BLOB_LOST_DEFAULT_WAIT
BLOB_LOST_DEFAULT_SPRINT
ROLLER_CHECK_DEFAULT
ROLLER_CHECK_BLOB_NEAR
DEFAULT_SERVO_SPEED
SERVO_SPEED_MAX
SERVO_SPEED_MID
SERVO_SPEED_MIN
SERVO_STEP
AUTO_ROLLER_ON
AUTO_ORTH_TURN_DELAY 18
AUTO_LONG_DELAY 70
AUTO_MED_DELAY 30
AUTO_SHORT_DELAY 12
FREQUENCY 20000;
• Responsible for capturing of commands
from the Blackfin camera and transmitting
the right movement instructions to the
drive train.
• setColorBins
Dynamically change the color bin range
that the camera searches for depending on
the mean color of the image.
• detectBlobs
Process the action that needs to be
performed from the data gathered from the
camera.
PCB Design
•Eagle Cad Software:
•Extensive Library Parts and Good tutorials on
the web
•Manufactured by 4PCB: Student discounts
PCB Design
• Traces have different widths depending on the amount of
current flowing
on them.
• Signal traces are thinner that power traces
• Ground Plane
• Combines surface mount parts with through hole.
PCB Design
PCB with the surface components mounted.
Project Management
Power
Drive Train
Remote Control
Luis
Jorge
Diego
Camera
PCB
Sensors
Programming
0%
50%
100%
Project Management
Expected
Final
Project Budget
Project Budget
Item
Amount
Item
Amount
Camera
$ 230.00
Camera
$ 171.56
Battery/Charger
$ 80.00
Battery/Charger
$ 60.35
GPS
$ 100.00
XBee
$ 91.45
RC Unit
$ 65.00
Ball Collecting Mechanism
$ 45.08
Chassis
$ 30.00
Chassis
$ 120.00
Sensors
$ 60.00
Sensors
$ 30.00
Motor/Wheels
$ 50.00
Motor/Wheels
$ 75.80
Electronics
$ 30.00
Electronics
$ 60.00
PCB
$ 55.00
PCB
$ 60.00
TOTAL
$ 700.00
TOTAL
$ 714.24
Project Challenges

Caster wheels affecting motion
◦ Solution:
 Compensate as much as possible in code

Missing connection on the board
◦ Solution: Soldered cables directly to the board
Project Challenges
Color Specification:
• The Blackfin camera takes
a range of colors to define a blob.
• A color blob is not a accurate
method for searching for a specific
object.
Possible improvements:
• Machine learning:
http://research.microsoft.com/en-us/um/people/viola/Pubs/Detect/violaJones_IJCV.pdf
• Edge finding
More Information
• All project information is available at:
 http://eecs.ucf.edu/seniordesign/su2010fa2010/g02/
Questions?