iPhone Controlled RC Car CE Senior Design II Jordan Bean Phil Doughty Xander Fiss Chris Murphy

Presentation Outline Introductions Project Overview & Major Goals – Network (Jordan Bean) Infrastructure Range Protocol Ideas – iPhone (Xander Fiss) Software User Interface Hardware SDK Networking – GumStix (Phil Doughty) System Networking Robostix Software – RC Car (Chris Murphy) 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

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 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 RITs WiFi Network Support for UDP and TCP Connections Remote Login via SSH

RoboStix Autonomous Microcontroller – Programmed independently Receives data over I 2 C bus from GumStix motherboard – No knowledge of I 2 C required – Programs freely available control Robostix from Linux System Calls over I 2 C 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 Dont 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 ModulesCostOur Cost Verdex Pro XL6P$169.00Provided By CE Department Robostix$66.42 Tweener$20.00Provided By CE Department Wi-Fi module FCC$44.52 NetPro VX$77.42 Serial Null-Modem Cable$ volt Power Adapter$10.00Provided By CE Department iPhone SDK Dev Program$99.00 Hobby Grade Remote Control Car$ Remote Control Car Batteries$75.67 Battery Charger$41.03 Project Totals$801.90$602.90