For the past few decades, cars have become more and more computerized. This makes them harder to fix while jacked up in your driveway, but those PCs make it much easier to diagnose problems with your ride. Get all your vehicle diagnostic information via an AutoTap OBD-II scanner. This device monitors the car's Engine Control Module for real-time and historical data when connected to the port tucked away under the car's steering column.

Because the AutoTap wasn't designed for permanent installation, we had to modify the unit to keep it powered off when the car wasn't running. (It fits under the steering column near the port.) A simple 5-volt relay controlled by the USB power switches the unit on and off, depending on the state of the PC.

Power Up!

We've added enough power-hungry electronics to our car to drain the juice from a freight train. Really. In fact, the battery died in our car during a photo shoot (admittedly, it was a fairly lengthy shoot). So in addition to making sure you don't leave everything running, you'll have to route the electricity carefully through your car using some specialized hardware.

Our power-distribution system is divided into two main branches, the PC-related power and the amplifier power. Each has a separate direct connection to the battery and a 20-amp in-line fuse, and each is switched using automotive relays connected to the car's accessory power source.

The PC branch uses a series of voltage regulators and manufacturer-supplied adapters to generate the various voltages required for each separate component. For example, while most of the devices are USB-powered, each hub requires regulated 5V power to meet the current demand. The specific details will depend on the exact model product you end up using. Oh, and the amplifier branch simply connects the Infinity Reference, which draws quite a bit of current on its own.

Needless to say, use extreme caution when attaching anything to your car battery, or when modifying anything powered. Always wear safety goggles, and never disconnect the battery while the car is running.