Transcript iPhone Controlled RC Car

iPhone Controlled RC Car
CE Senior Design II
Jordan Bean
Phil Doughty
Xander Fiss
Chris Murphy
Presentation Outline
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Introductions
Project Overview & Major Goals
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Network (Jordan Bean)
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iPhone (Xander Fiss)
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System
Networking
Robostix
Software
RC Car (Chris Murphy)
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Software User Interface
Hardware
SDK
Networking
GumStix (Phil Doughty)
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Infrastructure
Range
Protocol Ideas
Electronics
Power
Mechanical Components
Integration
Restrictions
Anticipated Problems
Power Requirements
Testing Strategy
Multidisciplinary Aspects
Cost
Introductions
 Jordan Bean
 Behavioral Model/Network Communications
 Phil Doughty
 GumStix RC Car Control Unit
 Xander Fiss
 iPhone Application Programming
 Chris Murphy
 RC Car Electronics
Project Overview & Major Goals
 Use the iPhone as a tilt-based human control interface for an RC
car
 System communication over Wi-Fi
 RC Car Electronics Interfacing
 PWM Channel Controlled Steering and Acceleration
 GumStix provides Wi-Fi  PWM Interface
The Network Infrastructure
 The overall existing RIT wireless network will be used for
iPhone to RC car communication
RC Car
Gumstix PC
iPhone/iPod Touch
PC
Steering
Control
Acceleration
Control
Serial
Console
Expansion
Debug
Serial
Console
Robotix
Expansion:
PWM
Channels
802.11B/G WiFi Comm.
Accelerometer
Touch Screen
Buttons
Built-in
802.11B/G
WiFi
WiFi
Expansion
802.11B/G
WiFi Access Point
Infrastructure
 iPhone will run a UDP client during operating mode, and a
TCP client for testing
 The GumStix will run a UDP server during operating mode,
and a TCP server for testing
 Overall model/testing environment will allow for early
testing and easy integration
Range
 The RC car will be able to operate within the range of the RIT
wireless network
 As long as UDP packets keep arriving at the GumStix control unit,
user control will be maintained
 If no packets are received within a predefined timeout period, the RC
car will automatically stop
 Maintaining visual contact with RC car is recommended for
operational feedback purposes
Protocols
 For operation, the UDP protocol has been initially selected
 Offers fast transfer of information to RC car
 For testing and in case of major UDP issues, TCP
communication capabilities have also been included
 Allows for guaranteed connection and transfer of data
iPhone Software UI
• Tilt Values Read in
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Real Time
Connect to
GumStix
On/Off Send Data
System Settings
Speedometer
iPhone Hardware
 Touch Screen User Interface
 Accelerometer Integrates to Obtain Ground-Relative Tilt
Data
 Accelerometer data put through low pass filter to ignore
sudden movement (drops)
 Built in Wi-Fi
iPhone SDK
 C for Low-Level OS Calls & Functions
 Objective-C for Cocoa Touch API
 Object Oriented
 Strict Superset of C
 Extensive Documentation
 Tutorials
 Example Code
 Includes Simulator for Speedy UI Development
 Does Not Simulate Accelerometer
Networking
 Connectivity Handled Behind the Scenes
 iPhone OS is essentially Mac OS X
 Traditional Unix Socket Programming
 Code written in C
 Libraries built into iPhone OS
GumStix (Phil Doughty)
 Embedded Linux OS
 Plug & Play
 Modules connect on
either side
 Network and WiFi
Modules were purchased
 Robostix Microcontroller Module was also purchased
GumStix Networking
 Linux Networking Stack
 Proven Reliability
 WiFi directly supported
 Needed to change 1 line of a configuration file to automatically
join RIT’s WiFi Network
 Support for UDP and TCP Connections
 Remote Login via SSH
RoboStix
• Autonomous Microcontroller
– Programmed independently
• Receives data over I2C bus from GumStix motherboard
– No knowledge of I2C required
– Programs freely available control Robostix from Linux System
Calls over I2C
• Contains MANY useful features
– 9 PWM Channels
– 8 ADC Channels
GumStix Software
 Simple Program
 Wait for UDP Data on a specific port
 Once data is received, adjust PWM channels accordingly
 Send acknowledgement packet (optional)
 If data is not received within a specified timeout period, turn off
PWM channels (safety)
GumStix Help and Thanks
 Initial Setup, Getting on the Network, etc.
 Charles Gruener
 GumStix/RoboStix programming advice and information
 Nick Palladino
 Eric Offermann
Electronics
 The RC car is powered by a 7.2 V, 3300 mAh battery
 Three wire servo
 6.0 volt VDD
 0.0 volt GND
 PWM (0V5V)
Powering the GumStix
 Several options
 Battery for the Nintendo DS or Sony PSP
 Rechargeable AA Batteries + Voltage Regulator
 Power directly from the 6.0 volt VDD servo wire
 Need to be extremely careful with the sensitive microchips
 Don’t want a showstopper
Mechanical Components
 RC Car will be run in training mode so that forward and
reverse only run at 50% of capacity
 Speed of the RC Car has to be governed in software
 Theoretically capable of going 35+ mph
Integration
 Ease of integration will be supported by the testing and
integration behavioral models
 Use of behavioral models as an initial standard will help to
avoid any integration problems
 Integration of the RC car and the GumStix control unit will
be done as early as possible
Restrictions
 It is highly recommended that visual contact be maintained
with the RC car at all times to ensure safe operation
 The RC cars operation is also restricted to within range of a
wireless network
 Overall speed of the RC car will be governed for safety
purposes
 Steering of RC car is limited to 90° in each direction
Anticipated Problems
 Real-time control of the PWM channel outputs
 UDP packet reliability
 Powering the GumStix control unit
Power Requirements
 RC Car
 3.3 Ah RC Car Battery x2 (~24 Watt-hours)
 Estimated battery life on a charge: 30 minutes
 GumStix
 Powered Separately from RC Car
 Requires 5 Watts at most
 Runs on 4.5V – 6V
Testing Strategy
 Module testing will be completed first
 RC Car
 GumStix PC
 iPhone
 Integrated project testing
 Forward, reverse, left, and right capabilities
 Edge of network operation
Multidisciplinary Aspects
 Carefully researched ergonomic user interface (Industrial
Engineering)
 Mechanized RC car (Mechanical/Electrical Engineering)
 Wi-Fi Interfacing (Network Administration)
 Carefully engineered and documented software (Software
Engineering)
Project Costs
Project Modules
Cost
Our Cost
Verdex Pro XL6P
$169.00
Provided By CE Department
Robostix
$66.42
$66.42
Tweener
$20.00
Provided By CE Department
Wi-Fi module FCC
$44.52
$44.52
NetPro VX
$77.42
$77.42
Serial Null-Modem Cable
$15.25
$15.25
5.0 volt Power Adapter
$10.00
Provided By CE Department
iPhone SDK Dev Program
$99.00
$99.00
Hobby Grade Remote Control Car
$183.59
$183.59
Remote Control Car Batteries
$75.67
$75.67
Battery Charger
$41.03
$41.03
Project Totals
$801.90
$602.90