Requirements Document
Big Dog’s Kryptonite
James Crosetto (Bachelor of Science, Computer Science and Computer Engineering)
Seth Schwiethale (Bachelor of Science, Computer Science)
Jeremy Ellison (Bachelor of Science, Computer Science and Computer Engineering)
Faculty Mentor: Tosh Kakar
Date: 11/3/08
Version: 4
Introduction
The idea of this project is to enhance an R/C car. It will demonstrate each of our
group member’s abilities to problem solve, task manage, and think creatively. Through
this project, we will design additional functionality for the R/C car using computer
engineering and computer science. With the addition of computer hardware and a camera,
our R/C car will be able to be controlled over a wireless network from a computer rather
then by a radio frequency remote. These modifications will increase the range at which
the car can be controlled as well as allow the user to control the car without needing to
have it in sight. Other features may be added as well – features such as the ability of the
car to retrace its route to a “safe” location if the network connection is lost.
We have begun research in areas we foresee as necessary for the success of this
project. The first area is determining how all of the parts of the R/C car work. These parts
include the motor, the power supply, and the speed and steering controls. The next major
area of concern is the wireless communication between the car and the user’s computer.
We need to determine the signal strength and network bandwidth necessary to stream
video to the user’s computer and still allow responsive control of the car. We also need to
determine a way to send signals to the car which control steering and acceleration.
Project Description
Our project will create an R/C car that can be controlled over a wireless network
from a computer. When an R/C car is purchased from a store its operating range is
limited by line of sight and the maximum distance from the car the radio frequency
controller can operate. With a fully successful project, both of these limitations will be
removed. The first step will be to add a camera and computer hardware to our remote
control car. Then, we will create a program which will allow a user to establish a
connection between the hardware on the car and their personal computer. The user will
be able to control the car and receive video feedback from the car through this
connection. Thus, we will have to design a circuit between the computer hardware on the
car and the car’s steering and acceleration controls. This circuit will take a signal from
the computer hardware and convert it into an appropriate signal that the car’s controls
will be able to understand. Successful implementation would provide unrestricted
operation (line of sight and distance from the controller are no longer factors) of the R/C
car within the range of the wireless network being used.
While the idea seems straight forward, there are many facets to this project. On a
functionality level, we will need to break the project up into subtasks which we can
complete and test individually before moving on to the next one. The first task will be
adding hardware to the car that can connect to a wireless network. Next, we will need to
connect this hardware to the steering and acceleration controls on the car.
Once the hardware issues have been solved, we will need to implement a program
that can connect to the hardware on the car over a wireless network. The car will be
identified via an IP address. First we will implement a basic program that will just be able
to send signals to the car. The signals will comprise steering and acceleration control.
Next, we will add a GUI which will incorporate the steering and acceleration controls in a
user friendly manner. Finally, we will display a real-time video feed from the camera on
the R/C car within the GUI.
Beyond the tasks outlined, we currently have the goal of designing the hardware
on the car with a safety retreat feature, which involves keeping a log of the cars actions in
memory. This will allow the car to retrace its movements to its starting point in the event
the network connection is lost. In the event this happens, we also would like to design the
computer hardware on the car and the program to automatically reestablish a network
connection if it becomes possible.
In order to complete all the intended tasks of this project, we will need to research
many things. The understanding of networks (both generally and the understanding
wireless networks specifically) will be essential. Our program needs to communicate
without fault over a wireless network to the hardware on the car and vice versa.
Understanding electric circuits is another researching task at hand. How do the
acceleration and steering controls work? How can we implement a circuit so the
computer hardware on the car can send signals to the car to make it change direction or
speed? These are some of the major issues that we will need to research to answer.
A minimally successful project will consist of a car that can be controlled over a
wireless network. This means we can send a steering or acceleration command with a
specific purpose, such as turn the car to the left, from the user’s computer and the car will
respond as directed within a couple seconds. This shows we have learned how to
establish a network connection between the hardware on the car and the user’s computer.
It will also show that we have learned how to connect the hardware on the car with the
controls on the car so that the car responds appropriately to commands. Thus, our
learning objectives will be satisfied.
Functional Objectives Summary
1. design and implement computer hardware for the car
2. design and implement the hardware on the car to convert a signal from the
computer hardware to a signal that the controls on the car can use
3. have the hardware on the car connect to a wireless network via TCP/IP
4. design a program to send control signals to hardware on the car
5. establish a connection between the hardware on the car and the program on
the user’s computer over a wireless network
6. establish full ability to control car (acceleration and steering)
7. establish video transmission from camera on car to GUI on user’s computer
8. implement memory of cars movements and ability to retrace them in the case
the network connection becomes lost
9. automatic internet establisher
10. full addition of any other accessory features
Learning Objectives Summary
1. Understand how communication over wireless networks work.
2. Learn how information can be both sent and received efficiently over a
wireless network.
3. Learn how to detect whether a wireless network connection can be established
and how to detect immediately when a connection fails
4. Learn how a circuit can be built to modify a signal (such as a change in
current)
5. Learn how a circuit can send a variable signal (this can be used to achieve
different speeds of the R/C car)
6. Learn how the acceleration and steering circuits work on the R/C car
Use Cases:
Use Case:
Open control interface application and select network settings.
Actors:
RC car driver.
Precondition: User needs to have the application in a location on their computer’s hard
disk. The network RC car and onboard hardware must be powered on.
Steps:
Actor actions
System responses
User Runs the application
GUI opens with a prompt to
create/connect to a network.
User Selects/creates a network
Application validates selection and
establishes a connection with RC
car’s controls and camera.
GUI displays live video feed from
camera and awaits commands
Control the network RC car’s motion via remote GUI app
RC car driver
To steer and propel the RC car from a remote location under the ideal
conditions of a stable connection between the RC car and the remote
control app.
Precondition: Open control interface app and select network settings use case. Mouse
cursor is located within video feed display area.
Steps:
Actor actions
System responses
User presses space bar
RC car accelerates in the forward
direction to a velocity determined by
the position of the cursor which will
act as a speed control in our user
interface.
User moves cursor around video display
RC car’s direction and velocity
controls react appropriately to
changing orientation of cursor.
User releases space bar
RC car discontinues acceleration,
eventually slowing to zero velocity.
Use Case:
Actors:
Goals:
User presses Ctrl+space bar
RC car accelerates in the reverse
direction to a velocity determined by
the vertical orientation of the cursor
on the video display and in a
direction determined by the
horizontal orientation of the cursor
on the video display.
User moves cursor off of video display area
vertical and horizontal orientation
are set to the last position of the
cursor before it left the area, until the
cursor returns to video display area.
Postcondition: The nature of this use case requires that any of these
steps may be performed in any order, so it is necessary that during
and after each step, the video feed continues to be processed and
displayed.
Use Case:
Actors:
Goals:
Precondition:
Steps:
disconnect from network and close interface application
RC car driver
gracefully disconnect from network and close program
Open control interface app and select network settings use case.
Actor Actions
System Responses
click disconnect button on GUI
Disconnects user’s computer from
the network. (car considered
dead)
kill program
Use Case Model
Task Breakdown
1. Design
a. Hardware Design
i. Design how car will be controlled
1. Determine what will be used to transmit signals to the RC
car’s steering and acceleration “boxes”
a. What kinds of signals will be used (RF or wired).
b. What will be used to transmit the signals (signal
generation).
2. Design signal acquisition hardware
a. Research networking and TCP/IP protocols
b. Research and decide what hardware will best suite
our on-board (on rc car) computing/networking
needs
c. test our system in increments
i. test remote computer to on-board
hardware communication
ii. figure out what we can use as output
from hardware
d. figure out what RC car’s hardware needs as input
(do testing on servo connections and determine
Voltages, etc)
e. research how to get input / output to agree or at
least shake hands.
3. Safety recovery
a. research an efficient way for on board system to
memorize all maneuvers made.
b. If signal is not recovered in a designated amount of
time (1 min) car should backtrack, using the
memory.
c. stop backtracking once car has a strong signal
again.
ii. Design video
1. Use a camera mounted on the car for visual feedback to the
user
a. research and design application to receive video
stream from camera.
b. first design dummy applications to communicate
with IP camera, using the VAPIX® API.
iii. Design how car and electronics on it will be powered
1. Design electronics to use car battery power or another
source
b. Software Design
i. Design user interface
1. Live video feed from camera on car is displayed
2. Current signal strength is displayed.
3. Controls for steering and accelerating are simple.
a. Possible use of a joystick or something similar?
4. Alert if signal is lost.
5. Alert if malfunction (such as loss of steering control).
ii. Design network connection to car
1. User side
a. Program will try to find car and will alert user when
a connection is established or if a connection cannot
be established (research network connections)
b. Signals must be generated based on user commands
to control the car. (write applications that send data
over network)
c. Program will monitor connection status to warn the
user when the signal is weak. (research how to
monitor our wireless signal)
d. Program has a scan function to continuously try to
detect a car if connection lost in a non-graceful
manner. (again research network connections)
2. Car side
a. Signals must be interpreted from user and then sent
to proper controls on the car (do a lot of testing
here)
b. Video feed must be interpreted and relayed back to
user program. (Using VAPIX® API, retrieve stream
from camera to our interface
iii. Design safety recovery
1. Car must keep track of movements and then be able to
retrace them in case of a loss of signal
2. If unable to acquire signal, car must be able to return to
area where it had a signal.
c. Purchase required hardware/software/books/etc.
2. Implementation
a. Car side
i. Build and test network connection hardware and software
1. Make sure computer on car can send and receive signals
2. Implement software interpreter on the car for signals
ii. Build and test controls
1. Connect computer to controls
2. Test whether signals sent to the car are converted correctly
so that desired actions actually happen (for example the car
accelerates and decelerates when it is supposed to).
iii. Connect camera to car
1. Test to make sure video is being sent to the computer on
the car and that it is then interpreted correctly for
transmission to the user interface
iv. Build safety recovery system
1. Test if car can safely navigate the way it came
2. Test that car finds a “safe” location if it is unable to recover
the signal.
b. User side
i. Implement and test network connection software
1. Implement software to establish a network connection to
car
2. Test to make sure it connects correctly to the car and that
the connection is “realized” by the software
3. Create signal generator
a. Test that signals are sent to the car and received
from the car correctly.
b. Test ability to control the car from the user side
ii. Implement user interface
1. Make sure all necessary information is displayed
2. Create video “window” for displaying video feed from the
camera on the car
a. Test that video is received correctly
3. Test that messages are displayed appropriately (for
instance, when a connection is lost the user must be
alerted).
4. Create easy to use help menu
iii. Implement user controls
1. Keyboard or joystick commands are set (and configurable?)
2. Test controls to make sure car reacts as it should.
c. Test full implementation
i. Stress test different aspects
1. Make sure system reacts correctly when a connection is
lost.
a. Make sure the connection can be reestablished.
2. Test when the network connection starts to get bogged
down (i.e. lots of quick commands)
3. Test unexpected closing of user program.
a. Car should enter safety/recovery mode.
b. User should be able to restart program and connect
back to the car.
3. Add additional features
a. Make sure they are reversible! (if something doesn’t work we should be
able to revert to previous working configuration without a problem).
4. Deliver the final product
Preliminary Timetable
Budget
Needed Materials:
User Side Computer
IP camera with minimal functionality
-
-
already have
$250-300
usable embedded system (preferably Linux)
on board wifi connectivity
usable signal output
tcp/ip, http protocol
Preferred additional functionality
- low power requirements
- supports encryption
- web server
- bandwidth efficient
- mpeg-4 compression
- interfacing API
RC car
Wireless Networking Bk
Linux Bk
Other Books/Manuals
Website
Development Languages:
Java
Processing
Vapix or similar API
Signal interpreting hardware
-
already have
Library
Library
Google/Library
Google Code
-
free
free
free
to be determined (not to exceed $50)
References
Various definitions and information obtained from pages on www.wikipedia.com.
http://www.networkcamerareviews.com/networkcameras/ - website with professional
reviews on most IP cameras on the market.
http://www.axis.com/files/datasheet/ds_207mw_combo_30820_en_0801_lo.pdf - detail
specs on the Axis 207mw: the camera we are interested in using.
http://www.axis.com/products/cam_207/ - basic info on the Axis 207
Books:
Lethbridge, Timothy C., and Robert Laganière. Object-Oriented Software Engineering:
Practical Software Development using UML and Java . New York: McGraw Hill,
2001.
Hunt, Craig. TCP/IP: Network Administration . Sebastopol: O’Reilly, 20012.
Manuals:
VAPIX® version 3 RTSP API Documentation.:
http://www.axis.com/techsup/cam_servers/dev/cam_http_api_index.php
Axis Network Cameras and Video Servers Embedded Scripting Guide: www.axis.com
Emails:
G, John. "Re: Engineering Student." Email to Futaba.
3 Nov. 2008
Glossary
Computer network: a group of interconnected computers.
Electric circuit: an interconnection of electrical elements.
IP camera: a unit that includes a camera, web server, and connectivity board.
GUI (graphical user interface): a type of user interface which allows users to interact
with a computer through graphical icons and visual indicators
Memory: integrated circuits used by a computer to store information.
Network Bandwidth: the capacity for a given system to transfer data over a connection
(usually in bits/s or multiples of it (Kbit/s Mbit/s etc.)).
R/C (remote controlled) car: a powered model car driven from a distance via a radio
control system.
RF (radio frequency): a frequency or rate of oscillation within the range of about 3 Hz
to 300 GHz
RTSP (Real Time Streaming Protocol): A control protocol for media streams delivered
by a media server.
TCP/IP: an entire suite of data communication protocols, including Transmission
Control Protocol and the Internet Protocol.
User Interface: means by which a user interacts with a program. It allows input from the
user to modify the program and provides output to the user which denotes the results of
the current program setup.
VAPIX®: RTSP-based application programming interface to Axis cameras.
Video transmission: sending a video signal from a source to a destination.
Wireless network: computer network that is wireless.
Signatures