Transcript Document

Deep Memory Automotive Data
Logger
Adolph Seema
Paul Kurucz
Motivation

Paul’s idea
Presentation Plan



Description of the project.
System Breakdown
 User Profile
 Software & System Design Constraints
Hardware-Software Interface
- OBD-II setup
- OSI-9141 and SAE-J1979
- Logging structure.
System Description
Modern vehicles contain a myriad of
sensors.
 Sensors are monitored by the engine control
unit (ECU) to determine the status of the
vehicle’s critical systems such as engine
speed, coolant temperature, fuel pressure
and intake air density.
 Most vehicles since 1996 have On-Board
Diagnostic (OBD-II) connector.
 Service Engine Soon light?

Goal
Design and implement a data logger that
communicates with the ECU via the OBD-II
connector.
Use the Dell AximTM X5 PDA as the data
logger and the user interface between the
OBD-II and the user.
Data logged should be compressed into a
Compact Flash that could be read by a Linux
station through the flash reader.
The Compact Flash Reader and the
PDA
Flash Reader and PDA Cont…
The reader accepts six types of flash media
 Compact Flash, Smart Media, Secure
Digital, Memory Stick, Micro Driver and
MMC multimedia card.
 The Dell PDA accepts three types of flash
media
 Compact Flash, Secure Digital and
MMC multimedia card

Golf TDI
Compact
Flash
Card
Dell Axim PDA
E
C OBD-II
U Connecto
r
RS-232 to OBDII Converter
RS-232
Level Converter
Level
Converting
Circuits
PIC
3.3 Volt Serial
Male to Male Crossover
Gender changer
UAR
T
System Components
PDA is the primary system controller that
provides the data logging and compression
services along with the user interface.
 The RS232 to OBD-II interface converter
contains a PIC micro-controller and electrical
interface circuitry.
 The interface converter allows the PDA to
communicate with vehicles that use each of
the three different physical layer protocols,
while only using one command set and baud
rate.

User Profile

After everything is connected and working
Three protocols possible to be implemented.
DMADAL
DMADAL
What do you want to do?
Please Select OBD-II
Protocol:
PWM (SAE 1850)
VPWM (SAE 1850)
KWP2000 (ISO 9141)
Data Logging
Diagnostic
Clear Check Engine
Continue
Continue
Choosing sensors to be logged and vehicle.
DMADAL
DMADAL
Please Select Sensors to Log:
Sensors being logged
Coolant Temp
Fuel Pressure
Engine RPM
In. Air Temp
Engine Load
Man Air Press
Car Speed
Fuel Pressure
500 Psi
In. Air Temp.
97 ºF
Man Air
Press.
Throttle Pos
1.5 Bar
Mass Air Flow
Wait/Stop
Continue
If we have time we will create a “database” of a few vehicles
Choosing specific log settings.
DMADAL
Specific Logging Settings
MODE
8
PID
3968
Intervals
5 ms
Total
Samples
Don
e
5000
Mor
e
Secondary functionality
DMADAL
DMADAL
1 Engine Codes Present:
Specify Vehicle
Make:
Volkswagen
Year:
2003
Model
:
Golf TDI
Code
:
P0001
Description:
An Engine Code
Continue
Go Back
If we have time we will create a “database” of a few vehicles
DTC description
Basic OBD-II Modes




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Nine (9) modes
Mode 1
 Vehicle speed, RPM, fuel system status, O2
sensor voltages, temperatures and timing
advance.
Mode 2
 A snapshot of mode 1 settings when a trouble
code condition occurred
Mode 3
 Retrieves powertrain trouble codes (P codes)
from the ECU. The ECU may not respond if
there are no trouble codes present.
Mode 4
 Clears all diagnostic and trouble code data.
Basic OBD-II Modes


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Mode 5
 O2 sensor test results on some vehicles.
Mode 6
 Non-continuously monitored test results.
Mode 7
 Continuously monitored test results.
Mode 8
 Requests control of on-board devices. Not well
defined
Mode 9
 Reports VIN # and calibration constants.
Software & System Design Constraints

Primarily Microsoft embedded Visual C++
(eVC++) for the GUI, C for basic libraries.
PDA-ARM
Processor
PDA
LCD
OBD-II.
INTERFACE
d
DISPLAY
STATION
LINUX
BOX
ENGINE
SENSORS
Software System Diagram
GUI
UI System Controller
Communication Core
Data Packetizer
OBD-II I/F Stack
Compression Library
(miniLZO)
Platform Independent
Serial I/F Library
File I/O Library
Windows CE Serial
System Calls
Windows CE File
System Calls
Windows CE File
System Calls
Error Code DB
Sampling Timer
SAE J1979 – App Layer
ISO 9141 – Data Link
Platform Independent
Accurate Timers
ISO 9141 – Phy Layer
Windows CE Accurate
System Timers
Formatting GUI requests

Two types
 Scheduler Request Format
 Query format
SRF
|________|
Mode
|________|
PID
QF
|________|
Mode
|________|
PID
|________|
Intervals
|________|
Sample Count
The Query Format Primarily for Secondary functionality
PDA Resources
The Dell AximTM X5 PDA has:
 Built in 32 MB of Flash
 32 MB of built-in RAM
 2 external flash storages including
 The Compact Flash, which can go up to
3GB
 We have 2 128MB Compact Flashes.

APPENDIX
[1] OBD II Interface Chip Data Sheet For PWM, VPW, and ISO 9141-2 Vehicles
http://www.obddiagnostics.com/DataSheet.pdf
[2] ODB Notes. A collection of a few fact on OBD-II
[3] INTERNATIONAL STANDARD IS0 9141 First edition 1989-10-01
[4] INTERNATIONAL STANDARD IS0 9141-2 First edition 1994-02-01
[5] SAE International, SURFACE VEHICLE STANDARD J1979 REV.
APR2002
[6] miniLZO Resource Center,
http://www.oberhumer.com/opensource/lzo/#minilzo
[7] Microsoft Developer Network, MSDN,
http://msdn.microsoft.com/library/default.asp?url=/library/enus/vcsample/html/vcorivisualcsamplesportal.asp
[8] Circuit Cellular,
http://www.circuitcellar.com/library/print/0103/Eady150/index.htm
[9] Stanford University Fact
http://www.stanford.edu/class/ee281/projects/aut2001/mp3player/fat16.htm
[10] eMbedded Development Ultimate Information Site, 2001, eVC++ Tutorial,
Daniel Lehtovirta http://www.justppc.com/evc1.shtml
Question Time