1. Group 12 Jason Mersch Victor Morales Victor Robles Danielle Anderson
ParkBot

2. Project Overview
Autonomous valet parking vehicle with search, park, and return functionality
Provides a low cost solution to automatic valet parking with potential use in real world vehicles
Cars with this functionality would have their own designated row of spaces

3. Requirements Front-end parking Cardboard surface with no incline
Avoid objects in path
Park in space without colliding with neighboring cars
All parking spaces uniform and designated
Return to drop-off position
Low cost to implement
Simulate potential real world environment
Battery powered

4. Specifications Minimum RC car dimensions: 15”L x 13”W Max Speed: 6 mph
Max search and park time: 5 minutes
Max pull out and return time: 5 minutes
Parked front end clearance: 3 in
Safe distance from obstacle during park search mode: 3 in (formerly 10 in)
Max cost: $400.00

5. Components Overview RC car platform
DC motor for forward and reverse propulsion
Motor speed and motor direction control
Steering servo for left and right maneuvers
LCD Display
Power Supplies
Transmitter/Receiver pair
Obstacle avoidance sensors
Microcontroller

6. RC Car

7. RC Car
Requirements:
Needed an electronic speed control module (ESC) w/attached motor to control the motor speed and direction .
ESC needed to be easy to interface with an Arduino microcontroller.
Needed 3-wire steering servo motor for easy interfacing with an Arduino microcontroller. (some, believe it or not, came with 5-6 wires)
Needed to have a large enough chassis to support multiple battery packs, obstacle avoidance sensors, and PCB. (minimum: 15” L x 10” W)

8. RC Car Comparison Option 1: Ready-to-run (RTR) car
Left/Right /Center steering (not proportional)
Large and fit budget, but did not have desired ESC for controlling motor speed and direction
Option 2: Hobby grade RTR car
Fully proportional steering
ESC for motor control
Large enough to fit all essential components on chassis, full function, fit budget
Purchased: Duratrax Evader EXT
Dimensions:
Length: 16.1”
Width: 12.9”
Height: 6.6”

9. Motors & Steering Servo

10. Motor Utilize existing motor in R/C car
Model: Duratrax Photon Speed 20
Operating voltage: 7.2 v – 8.4v
Max speed: Up to 30 mph

11. Motor Control Requirements:
Needed to control the motor’s forward and reverse direction
Needed to control the motor’s forward and reverse speed
Speed to be kept under 3 mph for accurate movement
Needed to support current draw of motor
Motor start-up could potentially meet or exceed 20 A.

12. Motor Control Options Option 1: Implement H-bridge IC
Easy interfacing with Arduino microcontroller.
H-bridge IC’s that supported up to 20 A per channel cost up to $50
Option 2: Use existing ESC on RC car
Model: Duratrax Sprint ESC with reverse
Maximum constant current for forward 128 A & for reverse 64 A
Chose to utilize existing ESC

13. Dynamite Tazer 15T Specifications: Dimensions:
Operating Voltage: 4.8– 8.4 V
Controls forward and reverse movement
Peak current 700 A
Continuous current 110 A
Designed for 20 – 27 turns motors
Dimensions:
Length: 1.7”
Width: 1.5”
Height: 1.1”

14. Steering Servo Use RC car’s existing servo Operating Voltage: 6V
3-wire servo motor
Speed 0.20 sec/60 degrees
128 oz-in torque

15. LCD Display

16. LCD Display Requirement: Description:
Display currently running function for viewing
Description:
Character Display
White text on blue background
Backlight
Standard Hitachi HD44780 controller
16 characters wide x 2 columns
Utilize six data lines (D4 – D7 )

17. Sensors & Remote Control

18. Transmitter & Receiver
Motivation:
Basic functionality
Send signal to begin parking spot search
Send signal to pull out of parking spot and return to point of origin
Allows for expansion if different wireless features want to be added

19. Transmitter & Receiver Methods Considered
Bluetooth
Too expensive to implement
Infrared
Poor range, line of sight
Wi-Fi
Components needed to implement system are too large
Chose: RF
Good range
Easy to implement on microcontroller chosen
Inexpensive

20. RF Transmitter MO-SAWR-A Transmits at a frequency of 315Mhz
Range up to 500 ft.
No line of sight needed for
transmission
Common in car alarm remotes, beepers, and many similar devices
Operating voltage: 2 to 12v

21. RF Receiver MO-RX3400-A Receives signal at 315Mhz from RF transmitter
Range of up to 500 ft.
Common in car alarm remotes, beepers, and many similar devices
Operating voltage: 5V
Current draw: 2.3 to 3 mA
Digital signal to
to microcontroller for easy
data processing

22. Sensors Considered Infrared Sensors Imaging Sensors
Sharp IR GP2D12 Sensor
450 –750 nanometer range of visible light
Covers a range of 10 to 80cm with a optimized distance of 24cm
Operating Voltage: 0.3 to 7 volts
Max current draw: 10mA
Imaging Sensors
TSL 1401 Linescan Imaging Sensor Daughterboard
128-pixel sensor chip
7.9mm focal length imaging lens
Operating voltage: 3.3 to 5 volts.
Max current draw: 5mA

23. Sensors Considered cont’d
Ultrasonic Sensors
Chose: Ping Ultrasonic Range Finder
Emit a short 40 kHz signal
Range 0.8 in to in (3.3 yd)
Operating Voltage: 5 volts
Max current draw: 35mA

24. Sensors Advantages and Disadvantages
Ultrasonic sensor
Fastest response time at 115 us up to 18.5 ms
Smallest at 0.84 in W x 1.8 in L
Best range at 0.8 in to in
Infrared sensor
Poor range
Imaging sensor
Slow response time
Expensive

25. Ultrasonic Sensor Considerations
The sensor must be mounted perpendicular to the floor for accurate performance
Echo-free environment for the most accurate readings
The object that the sensor will detect has to be large enough for the ultrasonic waves to deflect off of it

26. Ultrasonic Sensor Mounting
The small size of the sensors make it easy for mounting onto the frame of the car
There will be three sensors mounted on ParkBot one in the front and one on each side of the car
These sensors will be connected in series to keep the current draw low
Sensors will be mounted at different heights to determine optimal height

27. Power Supply

28. Power Supply
Decided to divide the power system of ParkBot into two separate power supplies:
One will power the drive motor and servo.
The other will power the remaining components.
Transmitter has its own power supply.
Voltage (V)
Current (mA)
Power (mW)
Sensors (x3) 5
105
525
MCU 40
200
Receiver 3 15
LCD 4 20
Voltage (V)
Current (mA)
Power (mW)
Transmitter 5 20
525
MCU 40
200
Voltage (V)
Current (mA)
Power (mW)
Motor
7.2 -
Servo 6

29. Voltage Regulation
Voltage regulation to 5VDC required for the following components
Microcontroller
Ultrasonic sensors (x3)
RF receiver unit
Rf transmitter unit
Decided to use a simple linear regulator for the power supply in order to power the components listed above. A LM7805 5VDC voltage regulator will be used.
Voltage Regulation to 6VDC required for the:
Servo system drive

30. Electronic Speed Controller
Main Power Supply
Chose: Duratrax 7.2V Ni-MH 4200mAh rechargeable battery pack.
Will be directly connected to ESC module (no voltage regulation needed).
Will be connected to a LM7806 6VDC fixed voltage regulator to power the steering servo motor.
Was chosen based on the amp/hours and voltage needed to properly operate the other components for the minimum time specification.
Electronic Speed Controller
7.2v Ni-MH
LM7806
Voltage Regulator
Steering Servo
Motor

31. Secondary Power Supply
Chose: Chose: Digital Energy 9.6V Ni-MH 1600mAh rechargeable battery pack.
Will be connected to a LM7805 5VDC fixed voltage regulator to power Ultrasonic Sensors (x3), RF Receiver unit, and microcontroller unit.
Was chosen based on the amp/hours and voltage needed to properly operate the steering servo and rear motor for the minimum time specification.
About 1600mAh/152mA = 11 hours and 31 minutes
Good amount of battery life for testing and running
LM7805
5VDC
LCD
7.2v Ni-MH
Microcontroller
Ultrasonic Sensors (x3)
RF Receiver unit

32. MCU

33. MCU Requirements I/O pins needed: Open source
4 digital (for obstacle avoidance sensors and RF receiver)
3 digital PWM (for DC motor control and servo control)
Open source
Well documented with online examples
Uses a familiar programming language
Sufficient memory and processing power
Operating voltage of 5V
Chose: Atmel ATMega328

34. MCU Specifications Atmel ATMega328
With Arduino Bootloader for use with the Arduino language
Arduino language based on C/C++
Max frequency: 20MHz
32KB of program space
23 I/O Pins
Operating Voltage: 5V

35. Pin Configuration Overview

36. Overall MCU Diagram

37. Programming the MCU
Use a SFE FTDI USB to Serial Basic Breakout Board that interfaces with the MCU
Optimized to work with 5V Arduino boards and cloned 5V Arduino boards
Easy loading of code onto MCU through USB port on PC
Cheaper than buying USB to serial converter cable ($33 vs. $14)

38. PCB
We decided to purchase a punchboard and utilize the Aruduino layout for the Atmega328 microcontroller.
We soldered the PCB after successful testing of the implemented parts on the board
Optimized Arduino configuration will be used for maximum performance for our system
Size: 4.5" x 3.3

39. Software

40. Testing Area Specifications
Our RC car is 1:10 Scale (scaled down to 1/10th the size of real world car)
Real World Measurements
Typical parking space
240 in L x 120 in W
Dimensions of average mid-sized car
185 in L x 70 in W
(120 – 70) / 2 = 25 inches in between parked car and left and right ends of parking spot. Multiply this number by 2 to get 50 inches in between the parked car and each of the neighboring parked cars.
Also there is an approximately 60 inch rear clearance assuming the car parks 5 inches away from the front barrier.
Scaled Down Testing Area Measurements
Dimensions of our RC car
16.1 in L x 12.9 in W
In order to achieve 5 inch (50 / 10) clearance in between parked cars and a 6 inch rear clearance (60 / 10), parking spaces in the testing area will have the following dimensions (left and right ends of the parking spot will denote the side of the neighboring parked car, not the ends of the actual parking space):
22 in L x 22.9 in W

41. Software Class Diagram
int occupiedSpotCount
Keeps track of the number of occupied left and right spots. Increments after each occupied pair of spots is detected
int openSpotLocation
Set to 1 if a left spot is available, 2 if right spot is available, and 0 if spot is detected as occupied
Servo steerServo
Servo object that will represent the steering servo
Servo esc
Servo object that will represent the electronic speed controller
ParkBot
int occupiedSpotCount
int openSpotLocation
Servo steerServo
Servo esc
+ void moveForward(int milliseconds, int dir,
int multiplier)
+ void straightenWheels()
+ void turnLeft()
+ void turnRight()
+ double timeToDistance(long sensorReading)
+ double getDistance(int sensorPin)
+ void searchForSpot(boolean search)
+ void park(int whichSide)
+ void pullOutOfSpot(int whichSide)

42. Collision Avoidance Algorithm

43. Parking Spot Search Algorithm

44. Parking Algorithm

45. Pull Out and Return Algorithm

46. Motor and Steering Servo Functions
void moveForward(int milliseconds, int dir, int multiplier)
Moves ParkBot forward for a designated amount of time and in the given direction (0 = forward, 1=left, 2=right)
void moveBackward(int milliseconds, int dir, int multiplier)
void straightenWheels(), void turnLeft(), void turnRight()
These functions straighten out the wheels of ParkBot, turn the wheels of ParkBot to the left, and turn the wheels of ParkBot to the right, respectively

47. Obstacle Sensor Functions
double getFrontDistance(int whichSensor)
This function will return the distance value read from whichever sensor is passed in the parameters. The parameter is the pin that the sensor is connected to on the Arduino
long timeToDistance(long sensorReading)
Sensor-read helper function. Takes in a time in microseconds (i.e. reading from an Ultrasonic sensor) and converts the time into a distance in inches (i.e. distance from nearest object to sensor).
According to Parallax's datasheet for the PING))) Ultrasonic sensor, there are microseconds per inch. Also the sensor reading in microseconds is the total time, outbound and return, so we must divide by 2 to get the distance to the obstacle. This gives us the following conversion:
distanceInInches = sensorReading / / 2

48. Algorithm Functions void park(int whichSide)
Does the process of pulling ParkBot into a parking spot. If the whichSide parameter is 1, ParkBot will pull into the parking spot on the left side. If the whichSide parameter is 2, ParkBot will pull into the parking spot on the right side
void searchForSpot(boolean search)
Does the process of searching for an open parking spot if the search parameter is true. If the search parameter is false, this functions is used to return to the point of origin
void pullOutOfSpot(int whichSide)
Does the process of pulling ParkBot out of a parking spot. If the whichSide parameter is 1, ParkBot will pull out of a parking spot that it pulled into on the left side. If the whichSide parameter is 2, ParkBot will pull out of aparking spot that it pulled into on the right side
Talk about what type of modifications will be made

49. Testing Scenarios The following scenarios were mastered:
Spot available on left
Spot available on right
Future endeavors:
No spots available
Spot too small on the left
Spot too small on the right
Detect traffic when pulling out of spot

50. Future Design Improvements

51. Administrative Content

52. Budget Parts Quantity Price Total Price (Incl tax & shipping) RC Car 1
$ 68.00
$ 81.51
Ultrasonic Sensors 3
$ 26.95
$ 80.85
MCU $ $
RF Transmitter $ $
RF Receiver $ $
Voltage Regulator 2 $ $
Battery
$ 26.99
$ 28.76
H-Bridge Chip
$ 2.53 $
PCB
$ 25.00
USB to Serial Board $
$ 18.95
LCD Display $
$18.75
Miscellaneous
$100.00
Total Budget = $

53. Timeline All parts ordered Feb. 10 All parts received Feb. 20
Initial component testing completed Feb. 25
Hardware circuitry completed
Mar. 1
Software completed
Mar. 10
Initial Complete System Testing completed
Mar. 25
Final testing completed Apr. 1

54. Questions???