2. Our Third And Current CarPC

The next vehicle to enter our garage was the Volkswagen Golf GTI 1.8T, which we purchased brand new. Being veterans of the CarPC world at this stage, we had begun planning well before we even received the keys.

For this build we set ourselves some objectives for what we wanted our CarPC to be like. Here were our specific goals:

The CarPC had to look OEM and match the car's existing gauge cluster colors. No permanent modifications could be made to the vehicle. No drilling, cutting or splicing of wires (and nothing that could void the warranty.) The system had to use the factory amplifier and speakers, but not the factory head unit. A 7" LCD touch screen had to fit in the existing radio opening in the dash. All wiring was to be in PET loom (also known as "expando sleeving") and hidden from sight. The car XM satellite radio had to be integrated and controlled by the computer. The CarPC had to have one PCMCIA slot for cellular Internet. The case was required to be the same size as a factory CD changer, using factory brackets.

With these requirements in place, we realized that lots of planning was needed if we wanted to build this within the cost and time budgets we had set for building and installing the completed system: $1400 and one week.

We started by taking a series of measurements of the car so that we knew how far we would need to extend the main wiring harness. This harness consists of the following:

The main power to the computer The ignition power (this tells the computer when to turn on) Two USB cables Power to the LCD screen A triple-shielded VGA Cable for the screen

This bundle of cables was made 19 feet long and strung though PET loom to protect the wiring from shorts and cut wires (Figure 1). This was one problem we encountered in our old car, where we found that we could have a wire break under the carpet for no apparent reason. Obviously this time we wanted to avoid that problem!

Figure 1: Wiring harness with and without PET loom sleeving

For this system we used the following hardware:

VIA EPIA MII10000 Mini-ITX Main board 512 MB RAM M1-ATX 90 W Smart Automotive power supply 2.5" 80 GB Western Digital WD800 Scorpio 5400 RPM laptop hard drive Panasonic Slot Load DVD-ROM/CD-RW Combo Drive CW-8124-B (24x24x24 speed) Lilliput 7" VGA Touch screen 619GL-70NP

We used the following software:

Windows XP Professional Street Deck