Thread: 1996 BMW 3-series Convertible

I've decided to at least attempt a carputer on a budget. The biggest goal is to have a very nice MP3 player; any other features are a bonus. I also want it to look factory and I'd prefer to stay away from color touch screens for now, partly due to the cost, partly due to the wiring, and partly due to their flashiness.

Car: BMW 3 series convertible
Screen: HD44780 compatible, size currently under consideration
Controls: Touch/Proximity(?)
Computer... whatever I have on hand, probably a 400-600mhz junker.
Function: MP3 Player, possibly display vehicle stats via OBD II link, possibly GPS?
Audio: Possible surround sound. All speakers in the car are controlled via a 5 channel amp mounted in the trunk. Implementing surround sound would be a piece of cake.

Constraints:
-MONEY!!!
-Space
-Speed/Reliabilty - I don't want to wait for a computer to boot so I can listen to my tunes!


Current ideas:
Computer *MUST* boot quickly, so a solid state disk drive will be used. The computer will hibernate when the car is turned off and return to its previous state when the car is turned back on. Minimal RAM will be installed to keep wake times to a minimum, hopefully 128mb - 256mb. The solid state disk will be a compact flash (CF) card mounted in an IDE adapter.

Eight separate buttons will be available. To minimize wiring, an eight to three encoder may be utilized to carry the control signals over three wires; a three to eight decoder will be used at the computer side to return the signals to their original state. Input will most likely be through the parallel port; USB is preferred if possible/easy. Buttons assigned:
0 -> Power/Mute
1 -> Vol +
2 -> Vol -
3 -> Play/Pause
4 -> Track + / Fast forward
5 -> Track - / Rewind
6 -> Folder (Playlist) +
7 -> Folder (Playlist) -

Buttons may be implemented through touch or proximity sensors. Budget, space, style and complexity may call for standard buttons.

If you know anything about:
-Interfacing with USB
-Proximity sensors (via the QT110)
-Software suitable for this project
Then please reply to this thread.


I'll try to keep this updated as stuff happens. Sadly, this means slowly as I only make it home every other weekend or so and I'm a broke college student.

My car:


and an old film shot:


Progress so far:

Originally Posted by Cyrix_2k

Mild progress...

I have a four wire solution for my controls thanks to a gem of a program by the name of "COM-port Winamp Control." It hasn't been updated in forever (and actually has to run in Win98 compatibility under XP), but it still works with Winamp 5. What's even more awesome is it's ability to do more than just control winamp - it can issue simple windows commands and can also be programmed to emulate keyboard strokes. This means I can set hot keys and have this program activate them simply by pressing a button on my dash. Also interesting is it's ability to natively support 15 buttons over an extremely simple serial port interface as well as assign different functions for each button when it is single clicked, double clicked, and held. Awesome!

Originally Posted by Cyrix_2k

Yes, I've been checking MP3car.com! Great site.

Mini update... I should have the controller online this weekend. Sadly, I bought a 15 pin DSUB instead of a 9 pin DSUB that I need for the serial port, so I'll need to get the correct part tomorrow. I did get my 4x20 display up and running though... It still remains to be seen if I'll be using the other display that matches the BMW illumination or this one. I'm strapped for cash, so I can't really buy anything extra at the moment

Originally Posted by Cyrix_2k

prototype...


The final version will be quite a but different. Better buttons will be used, hopefully the workmanship will be better, I will use the LCD that matches my car's illumination, and I'll probably implement a rotary encoder (maybe two?) for volume and/or track control.

I also installed a new (tinted) window in the back of my car. Plastic that's flexible at 90 degrees in summer != flexible at 20 degrees in the winter.