1. Wi-Fi Based Remote Exploration Vehicle Kevin Hicks Eric Offermann Nick Palladino

2. Outline Project Overview Control Station User Interface Embedded Computer (Gumstix) Vehicle System Testing System Integration Multidisciplinary Aspect Cost Questions / Demonstration

3. Project Overview

4. Control Station User Interface Objectives: –To provide an intuitive user interface for vehicle and webcam control –To efficiently communicate with the Gumstix onboard computer via TCP and UDP

5. Control Station User Interface

6. USB Peripherals –Logitech MOMO Racing Wheel and Pedals –Microsoft SideWinder 2 Joystick

7. Control Station User Interface Reading USB Peripherals –JInput API Open-source API for game controller discovery and poll input Provides the necessary function calls to obtains the current input values from the USB Peripherals When polled, the wheel / pedal / joystick axes return a polled value between -1.0 and 1.0 –Timer is created to poll the USB peripherals every 50ms

8. Control Station User Interface Webcam Display –MJPG streamer used with a specified URL –Frames Per Second calculated using a Timer object that triggers every second –User will be able to specify the video port to connect to on the onboard computer (default is 8080)

9. Control Station User Interface TCP Communications –Can connect using host name or IP address –After connecting, communication via TCP can take place to send commands to the vehicle

10. Control Station User Interface Encoding of Commands Current Methodology –Fill a char array with parameters until the end of the message, add a special EOM char (0xFF) to array, and then transmit to embedded computer Packet NameOpcodeParameter 1 Parameter 2Parameter 3Description SET_SERVO_POSITION0x00 Target Servo [1 Byte] Position [1 Byte] Set position of desired servo LOGIN0x01Password [8 Bytes] Client IP Address [4 Bytes] Client Port [2 Bytes] Request login LOGIN_RESPONSE0x02Successful [1 Byte] - - Response when LOGIN is requested LOGOUT0x03- - -Log user out of vehicle BATTERY0x04 Battery Life [4 Bytes] - -Remaining battery life (Wh) SPEED0x05 Speed in MPH [4 Bytes] - -Speed report from vehicle DRIVE0x06Direction [1 Byte] Speed [1 Byte] -Control for drive motor

11. Embedded Computer Gumstix Verdex with 400MHz Intel PXA270 CPU, 64MB RAM, 16MB Flash, microSD Power from 4.8V 2500mAh battery pack Linux 2.6.21 kernel and OpenEmbedded

12. Interface Block Diagram

13. Gumstix Expansion Boards Netpro-vx 10/100baseT Ethernet 802.11b/g Wi-Fi with additional module Breakout-vx Mini B USB port 40 pin breakout header with GPIO/PWM

14. Webcam Logitech MPS5500 RightLight Technology Capable of streaming 640x480 @30fps MJPEG video stream over USB 1.1 bus Convenient mounting system for attachment to servo pan/tilt hardware

15. Servo and ESC Communication 50 Hz PWM signals Generated in software with a package of kernel modules called pxaRC PWM signals output on 3.3v GPIO lines, have been verified to work with all servos

16. Current Sensor and Shaft Encoder Communication Data from the INA219 current sensor IC will be communicated digitally via I 2 C with port on breakout-vx Pulses will be counted from shaft encoder either onboard Gumstix or on external MCU pending final CPU load analysis.

17. Low Power Mode Embedded computer must enter a low power mode to preserve battery life Webcam will be suspended in software to enter low power state Wi-Fi interface will be brought down, will go up every 45s to check for communication requests CPU will enter a low power sleep state

18. Potential Onboard Computer Difficulties Consistent frame rate with varying signal strength Entering low power mode and bringing all hardware back up correctly

19. Overview of Car

20. Optical Encoder

21. Circuit Diagram of Current Sensor

22. Mounting components Mirrors for rear view Servos & speed controller Project Box for Gumstix Optical Encoder Batteries

23. System Testing Due to the scope of the project, incremental approach to testing is required Each subsystem (GUI, Gumstix, Vehicle) will be tested independently before integration with unit testing Building blocks include operation of Wi-Fi module, operation of pan/tilt mechanism for webcam, reading input from USB devices Specific test cases have been developed, including: –Turn wheel hard left, then switch to hard right position –Move joystick while the joystick is not engaged –Move joystick to extreme upper left, then to extreme lower right

24. System Integration Integration Timeline –Estimated two weeks for onboard computer and vehicle integration –Estimated one week to integrate vehicle/computer and Control Station GUI –Goal is to complete integration with at least one additional week for further testing

25. Multidisciplinary Aspect Mechanical Engineering –Allowable weight on vehicle, steering control, gearing ratio Electrical Engineering –Remaining battery life, analyzing current spikes, low-power mode requirements, speed control Computer Science / Software Engineering –Design principles in developing an intuitive UI, communicating via TCP

26. Estimated Cost ItemItem CostExpected Cost for Project Gumstix Verdex Pro XM4$129.00 Gumstix Expansion Board with WiFi Module$100.00*$0.00 Logitech MOMO Racing Wheel$90.00$0.00 Microsoft SideWinder ForceFeedback 2 Joystick$150.00$0.00 Logitech Communicate MP Webcam$55.00 Electronic Speed Controller$29.00*$0.00 Batteries$30.00*$0.00 Four-Wheeled Vehicle, motor, and charger$350.00$150.00 Lynx B Pan and Tilt Servos Kit$35.93*$0.00 INA219 Current Sensor (x 2)$9.26 MiniPCB for Current Sensor (x 2)$10.00 Optical Encoder QVE11233$1.00 Total$989.19$354.26

27. Questions / Demonstration