12-volt Plexiglass Computer

zootjeff writes: "I am in the process of designing and redesigning a computer for my car. This machine is based on the Shuttle FV24 motherboard. I built a box that is 8 inches by 7.5 inches by 3 inches. I also designed and built my own custom power supply. This could be useful to people who want to take linux into their car. It is also useful for solar powered battery operations." He sent some pictures, too, of what the 2nd case looks like, an overview, including (!) police report number (the 2nd revision was stolen), more on the power supply, and the third iteration.

The Linux car...

[Anonymous Coward]

It's already been done [dashpc.com]...

I don't use a DC powersupply though.

Lexan instead of Plexiglas

[caesar-auf-nihil]

One potential concern I see, especially with a car-bound computer, is impact resistance (potholes shake the unit around) and short-circuit fire safety. If you try using Lexan or Calibre sheet (polycarbonate) you'll improve the impact resistance of your case dramatically, and, the fire-resistance.

Plexiglass is notorious for getting brittle with heat and light exposure, both of which will happen if they sit in your car every day under the hot sun. One good summer could really do a number to the unit.

Mirror

[MxTxL]

/.'ed to hell. Mirror here. [internetforums.net]

Thumbnails won't work, but you didn't need to see them.

Re:Has anyone actually run the CAR on a PC?

[zulux]

Looking at the specs on my 1992 GM car - there is an onboard computer that controls the ignition timing - basically the timing is done by an almost analog circuit with the computer telling the circuit add or remove fuel from the mixture. Given how fast a piston moves in and out of the optimum range for firing the spark, it would be rather difficult to get a general computer and operating system to reliably send the signal to spark. There is a data bus that is available on most GM cars that will tell you all sorts of information - RPM, Fuel Mix Ratio, Governor speed and wheel speed etc. I'd rather have a computer that monitored the bus than have one that tried to replace the computers and circuits already in existence.

Re:Has anyone actually run the CAR on a PC?

[mach-5]

CAN!

Most automobiles use a standard called CAN (Controller Area Network) to report things such as ABS status, mileage, etc. All of these things are thrown out onto a two wire differential bus. I actually did my senior project using an 8051 microcontroller to interface with a CAN controller and display data from different engine parameters on an LCD. We used a dummy ECM (Engine Control Module) to spit out random data for testing. I'm sure it would be just as easy to design something for X86 architecture as well. The problem would be getting ahold of the development tools for the CAN controller, and a spare ECM to do testing. Also, the ECM takes an unheard of amount of power because there is a power spike when it turns on so you need a very large power supply to supply that spike.