CavComp MP3/Car Computer
The picture you see above is the splashscreen that comes up as the computer boots through DOS.
Overview
CavComp is a custom configured and assembled computer designed for use in my 1988 Chevrolet Cavalier. The basic idea was that I wanted an mp3 player I could use in my car, that had a lot of storage, unlimited possible uses, and was as cheap as possible to build. My original design involved a pentium class machine with a 2+ GB hard drive, built-in sound, and a PCMCIA slot with a wireless ethernet card installed for file transfers from my home PC. The computer would be powered by a DC to AC power inverter, and would be controlled by a custom keyboard interface built into the steering wheel. The display would be a 5" color LCD that I found on the web. As I began working on the design of the case, I decided that I didn't want to have it taking up space in my trunk (which would also be pretty cold in the winter), so I made the decision that it would have to be located under the front passenger seat. This allowed me to both hide it out of the way, and control the ambient temperature. This decision caused the box to turn out as it did in the hardware section.
Hardware
CavComp consists of the following hardware:
| Intel Pentium 133 with Heatsink |
| Zida Socket 7 AT/ATX Motherboard |
| 16MB DIMM SDRAM |
| Trident PCI 2MB Video Card with TV-OUT |
| Creative Labs Soundblaster AWE64 Value ISA Soundcard |
| 4.86 Gig Notebook Hard Drive |
| Custom Power Supply |
| PCI and ISA Right-Angle Adapters |
| Notebook to PC IDE Hard Drive Adapter |
| 104-key Keyboard and 3-button Joystick-style Mouse |
| 5" Color LCD |
| 10" x 8" x 2.5" Aluminum Enclosure |
| Assorted Cables and Connectors |
Software
The operating system I chose for the computer was DOS for several reasons. First, the boot time would be short. I know you can
modify Linux or Windows to achieve fast boot times, but this was easier as no modifications were necessary. Second, all of the system
resources could be allocated to playing music, which is, of course, very processor intensive. Third, DOS only requires a meg or two of
hard drive space (depending on what you install) leaving more for MP3 files. Fourth, no special shutdown hardware was necessary. I can just hit the power switch.
Finally, I could get away with less RAM and a slower processor than I would want if I was running Windows.
As the machine boots through DOS, a program called Blackout loads the picture shown at the top of the page. Not necessary, but it looks cool.
Installation
The installation was done on a single saturday (with the exception of the ashtray) with the help of my best friend.
(The pics were with his camera too. Thanks Slim!) The pictures below show the basics of it.
These are pictures of the joystick-style mouse embedded in the center console. This allows easy access for the driver or
the passengers. Being conveniently placed, I can use it without taking my eyes off of the road. The three buttons that I use for
operating the MP3 player are shown at the bottom of the controller.
This picture shows where the tape adapter comes out of the dash and into the receiver. The wiring runs behind the glove box, behind
the door trim, and under the carpet to the computer. The red and black square in the lower left corner of the picture is a
temperature indicator that I use to monitor the car computer to make sure it doesn't overheat, and that it is not too cold in
the car to fire it up.
This is a picture of the ashtray in the back of the center console. You can see that there is a keyboard plug-in, a serial port plug-in, and
a joystick port plug-in available. This is convenient for plugging in accessories. It was tricky to squeeze them all in there, but I managed it thanks to a dremel tool with a cutting wheel.
The ashtray still closes too, to keep dust and prying eyes away.
This is a picture of the back of the car computer under the passenger seat. All of the cables are routed under the carpet.
Also not shown is the rocker switch under the dash to turn on the computer.
Performance
The performance of the computer has been excellent. I have had no trouble operating the computer. It is currently operating at 133MHz (though it would have worked at 100MHz), and heat does not seem to be an issue. In fact, the temperature inside the case has been under 100 degrees F. The heatsink is moderately hot to the touch, but not excessively hot. I have not had any power up or vibration problems. It boots up and plays music in about 20 seconds, and the controls to operate the MP3 player have worked perfectly. The sound quality has been acceptable, but I didn't expect much from using a tape adapter.
Future Plans
There are no future plans for the system, as I had to get rid of the car because it had rusted away so badly. I still have the cavcomp computer and accessories, but I haven't done anything with them.