Preliminary Design Review 30 January 2007
Download
Report
Transcript Preliminary Design Review 30 January 2007
Preliminary Design Review
30 January 2007
Black Box Car System (BBCS)
ctrl + z:
Benjamin Baker, Lisa Furnish,
Chris Klepac, Benjamin Mauser,
Zachary Miers
Motivation
Car accidents
Provide proof of who was at fault
Provide information about force of crash
Other traffic incidents
Capture information about what really
occurred if ticketed for speeding, following,
etc.
Concept of Operations:
Goals
Provide visual information of car’s surroundings for
period of time before accident
Use accelerometer to determine if accident has occurred
Removable storage
If programmed acceleration level occurs, BBCS knows a crash
has occurred
Force reading will be saved in conjunction with visual data
Crash video can be viewed on home computer
Autonomous
In event of accident, data automatically saved
Powered by vehicle
CONOPS:
Requirements
Performance Requirements
Video requirements
- Camera outside of vehicle
- 5-20 seconds video recording loop
- 1-5 frames per second
Data storage
-
User interface
-
Video loop written to RAM
- In event of accident, data from each
camera written to Flash memory
Ability to view video of crash on home
computer
- LED indicator if data has been stored
- Ability to manually store/erase data
Block Diagram:
Main
Camera
Accelerometer
Black Box
User interface
Reset
Storage
Block Diagram:
Black Box
Reset
IC
Power
Main
Processor
Accelerometer
Camera
LED
IC
Camera
IC
RAM
or
LCD
Flash
Storage
Computer
Implementation:
Microcontroller
Flash-based, 16/32-bit
ARM
Microchip PIC
MSP430
Re-programmable
On-board ADC, UART, I²C, Timer/counter
Interface to sensors, Flash data log
USB 1.0/2.0 capable
Implementation:
Microcontroller
One main processor to act as a central
processor to control all coprocessors
Video processors, memory, accelerometer, etc.
Our design will use one processor for each
camera module
This will allow us to more easily implement
several video sources if extended
Implementation:
Video
We’re looking to use either a CCD or
CMOS camera as our video sensor.
Ideally we would like to use a camera with
USB output and onboard compression.
Using a webcam oriented device, we’re
hoping to eliminate any need to program
USB drivers. With a corresponding USB
microcontroller, this might be possible.
Implementation:
Video
Camera – STVS6522
Advantages
Only needs a 5V supply
Large range on input voltage (4.1-5.6)
Adjustable Frame Rate
Black and White or Color images
USB 2.0 compliant
Field of depth is infinite with a fixed focus
Implementation:
Video
Disadvantages
Operating range isn’t ideal for a full
automotive design (32-104 F °)
Minimum focus is 20 cm (~8 in)
Implementation:
Video Compression
We assume we are getting raw video from
an un-compressed CMOS camera
Estimated needs:
Moving JPEG conversion
Real time video compression (at least fast
enough to convert the first frame by the
time the second frame is taken)
Implementation:
Video Compression
Raw CCD Data
Buffered Storage
IC for Video Processing
I2C or USB to main IC
Storage for video processing
Implementation:
Video Compression
Video Conversion Types
Digital Camera Coprocessor
IC Programmed to do video compression
Ideal Setup:
CMOS Digital Camera coprocessor for digital still and
web cameras
Real time video conversion with 50:1 compression
ratio
I2C or USB data output
Implementation:
Video Compression
Suppliers:
STMicroelectronics
Motorola
BeyondLogic
Digi-Key
Implementation:
Memory
Fast re-writeable memory to buffer image data.
SRAM
Advantages
Disadvantages
Programming simplicity
Control simplicity
Expensive
Limited size
Requirements
Capable of handling 5 frames/sec video input
Low power consumption
Implementation:
Memory
Slow large capacity memory for image
data storage
Flash
Advantages
Disadvantages
Robust
Cheap
Slow access speed
Requirements
Compact Flash interface
Implementation:
Communication
Ideal Solution
I2C
USB 2.0 / 1.0
Fallback
Several I/O ports
Implementation:
Accelerometer
We’re looking at using a MEMS based
accelerometer to detect a crash.
The accelerometer is the central trigger
for the system.
The entire black box is in a looping state
until the accelerometer interrupts and sets
the system into its crash procedure.
Implementation:
Accelerometer
Accelerometer - LIS3LV02DQ
Advantages
3 axes (crash from above?)
I2C/SPI output interfaces directly with
Microcontroller
Factory calibrated with offsets loaded on
startup
Variable sampling frequency
Implementation:
Accelerometer
Disadvantages
2.5 V operation (increasing complexity with
power supply)
Configurable to +/- 2 or 6 gs
Might trigger too easily
Implementation:
Power
We assume we are getting power from a car
battery that varies from 8-16V.
Estimated needs:
One 12V-1A converter for cameras and
sensors
One 5V-5A and a 3.3V-5A converter for
processors, memory, and other circuitry
Implementation:
Power
Car Battery(8V-16V)
12V-1A Converter
5V-5A Converter
3.3V-5A Converter
Cameras, Sensors, Etc.
Processors, Memory,
Other Circuitry
3.3V Processors and
Circuitry
Implementation:
Power
Supply Types Available:
Linear Voltage Regulators
Switching Converters
Ideal Setup:
12V-1A, buck-boost
5V-5A, buck
3.3V-5A, buck
Implementation:
Power
Designing the Supply
Hard way: Design it by hand, go through
plenty of equations, and have a less efficient
converter than one you can buy for cheap.
Easy way: Go to National Semiconductor, go
to the Power Webench, type in your input
voltage and your output voltage and current
and it designs it for you.
Implementation:
Power
The result for a 12V-1A Supply:
Implementation:
Power
Suppliers:
National Semiconductor
Texas Instruments
STMicroelectronics
Analog Devices
Many, many others
Implementation:
User Interface
Ideal Solution
Plug into computer and all video sources
show up and start to run
On-station displays (LCD or LED on box)
Fallback
Data display in Windows Application (Excel,
Visual Basic, etc.)
Data dump to HyperTerminal convert video
using program then view video sources
Implementation:
Enclosure
Ideal Solution
Custom Plexiglas enclosure
Weatherproof
Transparent (for Expo)
Strong and Shock resistant (protect equipment in the event of
collision)
Fallback Solution
Generic electronics enclosure
Locking metal box
Some foam to lessen shock
Contingency Plan
No video altogether
Instead, base system around inputs of speed,
acceleration, braking, blinkers, lights, etc.
directly from car
Extensions
Other sensors
Speed
Lights, blinkers, brakes
GPS
Four video sources instead of one
25fps, 30 second video loop
Testing
Skateboard with system attached to it
Push skateboard into wall (collision)
Kick skateboard (side collision)
Drop basketball on top of car (falling rocks)
Hold bacon behind car (Cop with false ticket)
Division of Labor
Video: Chris Klepac
Compression: Zach Miers
Power: Ben Baker
Accelerometer: Chris Klepac
Microcontroller and misc. sensors: Lisa Furnish & Zach
Miers
Enclosure: Ben Mauser
User Interface: Ben Mauser
Documentation: All
PCB Design: Chris Klepac & Ben Mauser
Schedule
Questions