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?
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. Goal
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
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
Choosing sensors to be logged and vehicle. If we have time we will create a “database” of a few vehicles
Secondary functionality If we have time we will create a “database” of a few vehicles DTC description
Basic OBD-II Modes • 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 • 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.
Formatting GUI requests • Two types • Scheduler Request Format • Query format SRF |________| |________| |________| |________| Mode PID Intervals Sample Count QF |________| |________| Mode PID 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  OBD II Interface Chip Data Sheet For PWM, VPW, and ISO 9141-2 Vehicles http://www.obddiagnostics.com/DataSheet.pdf  ODB Notes. A collection of a few fact on OBD-II  INTERNATIONAL STANDARD IS0 9141 First edition 1989-10-01  INTERNATIONAL STANDARD IS0 9141-2 First edition 1994-02-01  SAE International, SURFACE VEHICLE STANDARD J1979 REV. APR2002  miniLZO Resource Center, http://www.oberhumer.com/opensource/lzo/#minilzo Microsoft Developer Network, MSDN, http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vcsample/html/vcorivisualcsamplesportal.asp Circuit Cellular, http://www.circuitcellar.com/library/print/0103/Eady150/index.htm Stanford University Fact http://www.stanford.edu/class/ee281/projects/aut2001/mp3player/fat16.htm eMbedded Development Ultimate Information Site, 2001, eVC++ Tutorial,Daniel Lehtovirtahttp://www.justppc.com/evc1.shtml