Computerizing Saab 900 with eeePC and custom software

**quartic** · 06-03-2010, 02:58 PM

It all started with a wish to just listen mp3s in my old Saab...
The car is 94' Saab 900 SE 2.0T, ca 180kW. Mods: Nordic Stage 3 mapping, SpeedParts 3" full length sport exhaust, JR air filter, Koni yellow dampers with lowering springs.

First, I wired aux connector to tape deck to provide line in for player. But it wasn't working advequately.
Car computer idea took place when a friend offered me one raw unframed 5,6" LCD with controller. It was just the right size to replace head unit of my car and I took it.

User interface
This is a budget project, so I decided to use my existing eeePC 901 instead of buying complete car pc solution. I couldn't find any fitting touch panel for fitting with LCD, and for trying something different, I decided to use old fashioned button interface. So I developed appropriate front end. I used telephone keypad for buttons which is interfaced with PIC microcontroller. It sends button responses to eeePC via RS232 interface.

Hardware
eeePC is located in glove compartment (it fitted exactly fine, no extra fastening). LCD panel is mounted in old head unit console. I added some frame fragments to it to merge with car dashboard. LCD controller and PIC controller board is mounted behind LCD panel. There is also DC-DC converter mounted behind all of it. GPS module is located on top of dashboard.
To turn on/off eeePC, there is button behind ashtray connected to connector I added for eeePC. This leads to power button inside the computer. I also removed the magnet from display which prevented to switch eeePC on when lid was closed.
For audio, I use old 80s Pyramid 4x30w stereo amplifier which I found from electronics shop. That was in box and unused! It required some rewiring for functioning properly for accepting pc and players audio output levels. I installed the amplifier below dashboard aside of passenger's leg room. Speakers remained stock. For volume adjustment, I use simple stereo potentiometer. I couldn't get my eeePC to accept audio line in for FM radio use. So I made simple relay based audio splitter. It switch between radio and computer line out. It's controlled by front end software. FM Radio is USB controlled module from CarTFT.

hardware listing

PC: Asus eeePC 901 20GB SSD
LCD: EG Display & System model BLB064V02-FA
Power Supply: mini-Box DCDC-USB
Tuner: CarTFT USB FM Radio module
Secondary Tuner: KWorld VS-PVR-TV 303U
GPS: GlobalSat EM-411
OBDII: ElmScan ISO USB
Internet: Huawey E1752
Button interface: standard telephone matrix keypad
Button interface controller: custom PIC18F4550 based board with ADXL202 accelerometer
RS232 Adapter: RS USB to 2x RS232 Converter
USB Hub: Trust 4 ports
Amplifier: Pyramid 4x30W

Most parts used in project

Inside glove compartment (audio splitter, FM tuner, USB hub, LCD button bar, USB memory stick with holder and eeePC)

Stuff behind LCD display. (keypad waiting for appropriate stickers)

Installed LCD, keypad, on/off switch and volume control

Inside eeePC (that white wire leads from power button to fitted external connector)

Software
Instead of choosing front end software from fine existing applications, I began to develop one from scratch. One reason was that I plan to use many custom applications in my car, other is that I started to learning OpenGL and this application is good ground for learning the basics. I use Delphi 6 for development.
My front end is oriented for button interface. With four navigation buttons, it's possible to do most operations. Additional buttons are used in FM Radio presets, etc.
Application have interfaces for FM Radio, Music, Video, Navigation and Car Diagnostics. For radio, front end is communicating with FM Radio Module directly through virtual COM port. For audio, playback is done by Winamp by controlling it through Windows Messages. Video playback is performed by Media Player Classic which is controlled by sending key presses. For Navigation, there is Garmin Mobile PC, controlled similar to MPC. Car diagnostics interface is unimplemented yet, but it will get direct communication with OBDII adapter through virtual COM port. In addition, I have telemetry window where can be seen some GPS data and acceleration data in two axis. Settings window, where can be adjust some parameters and seen Battery information and so. Mobile parking vindow, where is option to park your car using mobile phone to send appropriate sms. This is accomplished over bluetooth connection with my phone through AT commands.

software listing

Windows XP Pro
Custom front end
Winamp
Media Player Classic
Garmin Mobile PC

Main view from front end

FM Radio interface view

Winamp interface view

Media Player Classic interface view

Telemetry view

Parking view

Further plans
Finish OBDII software interface to see main engine readings realtime.
Refining head unit appearance.
Replace USB hub (now it has only four ports and it appears to be only USB1.1 instead of 2.0 stated on package)
Replace GPS with 10Hz device to get some performance data.
Add reverse camera.

**Gregoodom** · 07-19-2010, 03:35 PM

Ive been getting conflicting report on the status of the odb on our car is it possible to use the standard odb2 code reader on the 1994 Saab 900s 2.3l 4cyl. please let me know as soon as posible i like the computer you have, if i had the money i would copy ur set up sweet

Thanks

**quartic** · 07-20-2010, 10:19 AM

Originally Posted by Gregoodom

Ive been getting conflicting report on the status of the odb on our car is it possible to use the standard odb2 code reader on the 1994 Saab 900s 2.3l 4cyl. please let me know as soon as posible i like the computer you have, if i had the money i would copy ur set up sweet

Thanks

Before purchasing scanner, I wasn't sure coz diagnostics port is required since '96. But it works in my '94 car and read codes and live data just fine. It uses ISO protocol, so I'm using Elmscan ISO USB tool (tried with Scantool and PCMScan software). Universal devices should work too. Maybe you should consider to try another device.