Overview:
Here, I will cover only the basics of 'CarPuters'. A carputer is simply a computer in your car. It can be as simple as a standard PC in a tower enclosure running from an inverter or it can be a custom built unit that's about the size of one volume of an encyclopedia. CarPuters are generally used for playing MP3s and many people use older computers that are too slow for other applications. Newer, faster computers can be used if you want to use it for gaming, movies, music videos and other such processor intensive applications. If you travel a lot, you can add a GPS module and map software.

Operating Systems:
While you can use an operating system like Windows XP on faster computers, you will need other options for slower computers. Some people are using a scaled down version of Win98 or one of the Linux distributions. There are even 'front ends' that are designed especially for carputers.

Booting Up and Shutting Down:
As you know, it takes a few seconds for a computer to reboot. If you have to wait for a minute or more for your music to start every time you enter the vehicle, you won't likely be satisfied. There are several ways to overcome this.

1. You can use hibernation in XP. This will allow the computer to boot within about 10 seconds if properly setup.
2. You can use an operating system that is relatively small.
3. You can use a dedicated power supply controller that doesn't turn the computer off for a certain period of time (10-20 minutes). That way, the system will be up and running if you leave and return to the vehicle after only a short period of time. If only on for a short period of time, the computer will not drain the battery. One note on this type of system... You will typically need a specialized power supply or a dedicated battery with a battery isolator if the computer is to remain on when you start the vehicle.

Power Supplies:
There are several types of power supplies. The simplest is the inverter. It converts 12 volts DC to 120 volts AC and you simply plug your computer into it. Although it's simple, it's not the best. It can induce 60Hz noise into your audio system and is cumbersome. A larger inverter (needed to reliably run a fast computer) will be as large as a small to medium sized car audio amplifier. There are dedicated power supplies that regulate the 12 volts to the lower voltages needed but they are generally for low powered systems. There are dedicated switching power supplies. These take 12 volts DC in and generate all of the various voltages needed by the computer. The best ones can handle high power systems and graphics cards. They can also keep the computer from rebooting when you crank the vehicle (with no isolator or second battery).

The following are some of the power supplies currently available:
http://www.opussolutions.com/
http://www.carnetix.com/CNXP1900.htm
http://www.powerstream.com/mini-itx.htm

Monitors:
There are several 5-7" monitors that are available for use as an in-dash monitor. These have the same input as a standard computer monitor and will provide a much clearer picture than a standard LCD monitor sold for standard video. If you have a lot of space, you can use a standard desktop type LCD monitor. Some of the monitors have 12 volt DC inputs and can likely be run from a regulated 12 volt supply. If you have one that has only 120 volt AC input, you can run it from an inverter. Some of the specialized in-dash type monitors have touch-screens. These greatly simplify using the computer because you don't need a mouse.

Mice:
As was mentioned above, some monitors have touch-screens. These can be used to make the desired selections on the screen. If you want to use a mouse, there are several wireless mice that will make the install cleaner (no wires to get in the way). If you don't have the space for a mouse to move, you can use a track-ball type mouse. They can be solidly mounted and don't require any more space than it's footprint.

Keyboards:
As with the mouse, there are wireless keyboards. They range from full sized units with multimedia controls (volume, FF, RW, play, pause) to small laptop sized units. There are even some (wired) keyboards that fold up or roll up to get out of the way until needed.

Keeping the Computer Cool:
As you know, computers generate a fair bit of heat. Computers with faster processors will produce more heat than slower processors (all else being equal). If you're going to keep a fast computer cool in a vehicle, you can do a couple of things. If there is enough available space, you can install the computer in the passenger compartment. There, it will at least have reasonably cool air to help keep it cool. If the computer is going to be installed in the trunk of the vehicle, you will need to provide sufficient air flow to keep it as cool as possible. If you're using a fast computer, additional air flow may not be sufficient. In that case, you may need to UNDERclock it. This is the opposite to overclocking. When underclocked, you may be able to run it at a lower voltage. This will allow the computer to run even cooler. I strongly recommend that you enable the automatic shutdown in the BIOS to protect the computer.

Motherboards:
In desktop/tower computers you can use virtually any motherboard. Since space is generally at a premium in a vehicle, you will likely need to run a small board. The smallest ATX boards are the micro and flex ATX boards. If you want something smaller, you will need to look into ITX boards. Some ITX boards are barely larger than the main board in your head unit. These typically have integrated processors that are only moderately fast when compared to the average AMD/Pentium computers. As far as I know, all of the ITX boards use VIA processors. The following link will help you familiarize yourself with what's available.

http://www.via.com.tw/en/initiatives/spearhead/mini-itx/

The best resource I've found for CarPuter information:
http://www.mp3car.com/

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