System Diagram
This project is interesting both for the number of subsystems the PC can work with—at least communications, audio, video, navigation, and engine diagnostics—and the options you have for building the PC and the interfaces. Figure 10-1 shows the overall concept for the Car PC; we expect any given version will implement a subset of the ideas in Figure 1, and may add others. The server and communications group includes not only the PC itself, but the audio and video sources, the navigation source, and the radios. The power group provides both 12 VDC and 120 VAC (or 240, depending on where you live). The audio video group implements the display outputs for computer interface, navigation, and video, and the audio outputs for music and computer voice interface. The sensor group watches the environment, providing driver or navigator inputs, listening for radar scans, and monitoring the engine status. You could add a forward-looking infrared video camera if you drive at night a lot.
FIGURE 1: System components
The interfaces to the devices in Figure 1 are each very different — power, analog audio, video, and networking, for example — so you’ll likely use independent connections for each of them. The resulting large volume of cabling requires that you think about cabling and grounding very carefully. An installation with loose wires running everywhere not only won’t look very good, it won’t be reliable in the long run, either.