My goal was to build a computer that I could put in my car (2002 Chevy Tahoe Z71) to play MP3s through the factory stereo. I wanted the computer case to fit under the rear seat and still allow the seats to be folded down. I had already decided to use the BookPC size motherboard (Model bki810E V7.3) because it had almost everything onboard and I had already had great luck using it for my HTPC (Home Theater PC). My next task was to try to find a case that would look good, be the right size, and be sturdy enough for the automotive environment.
Enclosure:
I decided that an old Sun External CDROM case (Model 611) might be a good choice.
The physical size was right for the motherboard leaving me some extra room for peripherals in the box. It already had cooling vents in the sides and I could mount the slim DVD ROM drive where the CDROM used to mount. I simply removed the power supply and drive sled to make enough room for the components. I had to cut the rear platic panel off and cut a hole in the rear metal panel to allow the connectors to protrude through the back. I also removed a couple of small platic tabs on the lid that were interfering with the Hard Drive and Power Supply. I changed the LED in the front to a blue LED and added a current limiting resistor to allow it to be drive by +5 from the DC/DC power supply.
Motherboard:
The motherboard used is a BookPC bki810e V7.3. It's features built-in Ethernet (Realtek Chipset), Audio (C-Media) including S/PDIF, Video (i810), TV-OUT (MBI TVPro), ATA100 (1 Channel, 2 Devices), Floppy, RS-232C Serial (Single Port), Parallel (Single Port), and USB (Dual 1.1). The small form-factor along with the very inclusive onboard peripherals makes this board the perfect candidate for a carputer.
The motherboad uses the ITE 8712F LPC Environmental control chip to support thermal monitoring, fan speed control, IRDA, and a host of other functions. One of the features of the LPC chip (that is not used, but is supported in the BIOS) is the Consumer IR (CIR) port. This port allows an IR receiver module to be connected and used to receive signals from almost any household remote. This will be discussed in more detail in a later section.
@TODO: Thermal Monitoring
@TODO: Fan Control
The bookPC supports the Pentium III and Celeron III (Coppermine core only - small bl\ue die in the middle) with a front side bus of either 100 or 133Mhz. The biggest problem with the fast versions of the Pentium III (faster than 600 Mhz or so) is cooling. In order to use a faster Pentium III, you must ensure that the processor is adequately cooled. Another option is to use a Pentium III based on the Tualatin core (Large silver heatsink embedded in the processor) along with a Socket 370 Adapter. The Socket 370 Adapter provides the correct core voltage need by the Tualatin (usually 1.5V as opposed to 1.75V for the Coppermine). I am currently running a Celeron III 1.4Ghz (100Mhz FSB) with an adapter with great results.
@TODO: Memory Support
Power Supply:
The PW-120 ATX DC/DC power supply and the ITPS power sequencer work together to take the unregulated 10-14 volts from the car's electrical system and provide the +5VSB and +12V needed by the bki810e.
In
order to help survive the drop in voltage of the cranking of the
engine, a Gel-Cel battery and DIode circuit is placed between the ITPS
and the constant +12V from the car.
Networking:
Removable Media:
Display Unit/Remote:
Software: