carputer

 

A Carputer, or 'CarPC', is a general purpose computing platform installed in a vehicle. As of the early 21st century, no OEM or major aftermarket supplier offers or supports carputer-class installations, limiting the installed base to the hobbyist, enthusiast and entrepreneur communities. In use as early as 2004 ^[1], the term generally refers to contemporaneous personal computers retrofitted in a production model car.

Since typical carputer installations enhance or replace the car's "radio", it can serve as a ready and recognizable comparison:

• Each vehicle contains an OEM system, or the capacity to install one.
• Default systems are upgradeable either with OEM or aftermarket parts.
• Upgrades can be integrated such that they appear consistent with the OEM look and feel.
• The type and capacity of upgrades is extremely broad.
• OEM development generally follows aftermarket development with a lag.

Carputer systems are usually built from traditional desktop components, particularly the increasingly compact small form factor systems. Laptops serve a particularly useful role as carputer system components, but because they cannot be cleanly integrated into the car they are not considered carputers in and of themselves.

Though not carputers per se, laptops are an excellent proxy when comparing carputers to an OEM or aftermarket integrated solution. For instance, as of 2007 GPS navigation is a common OEM equippable option and roughly equates to a laptop running GPS software. Actually doing the comparison across a few dimensions is illustrative:

	OEM or Aftermarket	Carputer	Laptop	Comment
Interface	Good	Good to Excellent	Excellent to Poor	Wireless keyboard dramatically improves carputer address input, while attached keyboard degrades laptop.
Reliability	High	Average	Average	OEM systems are simpler. Users blame crashes on OEM, not OS.
Expandability	Very low	Very High	Very High	OEM system may have a few expansion modules, carputer/laptop can run any software available
Price	Very High	High	Low	Carputer and OEM system are both low volume, custom systems, but carputers use commodity hardware. Laptops are commodity hardware.
Estimated Retail (2007)	$1,800	$1,200	$1,000	Approximate "Out-The-Door" street prices, including parts, labor and software.
Availability	Very High	Not available	Very High	Carputers require custom design & installation.

Typical system

A typical Carputer system is composed of four parts:

• Machine
• Display
• Interface hardware
• Power Supply

Machine

The machine consists of a motherboard, processor, memory and data storage method. Data storage typically consists of a hard drive or solid state flash memory. Small form factor and low power consumption typically require the use of a micro-atx, or mini-itx board. Carputers are also available second-hand as aftermarket additions.

Screen

You have to be able to command your carputer system. Preferably, this process should be as easy as possible. Initial carputers (pre-2000) typically used LCD character displays to interface and play music. Commands were typically sent to the carputer by means of a keyboard. Not far after the initial advent of the carputer, many people started using a wireless serial port remote to control their machines. This was about the time that small TV screens became affordable. The majority of the first (affordable) carputer screens were RCA video input only.

This awkward phase of sub-par display devices was frustrating to the carputer community. Users had difficulty justifying $1000+ for a nice screen, and for the most part, screens that nice were rare or just unavailable. Modern screens are leaps and bounds better than those just a few years ago.

The most common modern-day screen that people use is the 7 inch VGA touch screen. Typical models used are Dynamix, Lilliput or Xenarc screens, preferably console-mounted in a double din adapter, but if needed as seen in these marketing pictures:

(Images provided by Mobile-Effects.com)

Interface Hardware

In addition to the display unit, many other options exist to interact with a CarPC in a manner that does not distract the driver from the most important task - keeping the car on the road.

In 2005, users were beginning to experiment with Heads Up Display options, although these are typically custom built rather than mass produced.

Bluetooth devices are commonly used in the CarPC environment to wirelessly connect to GPS devices, mobile phones, or keyboards used to manage and maintain the system.

Other alternatives for control involve the use of either IR or RF connected remote controls for hands-only, driving-friendly control.

Power

The most basic question those new to Carputers have is how to power the machine. Laptop users have an easier option, use of internal batteries. All other Carputer machines need one of two methods for power. One method is the use of an inverter, the other is the use of a DC-DC power supply.

Generally, houses (where computers are normally designed to be used) used AC (Alternating Current.) Automobiles, on the other hand, use DC (Direct Current.) PC power supplies are made to be used with Alternating Current. DC to DC power supplies are sold at most carputer sites and are designed specifically for powering PCs in automobiles.

On a side note, when cranking a car the stater normally draws so much power that all other non-essential devices temporarily lose power. This normally would cause a booting computer to suddenly lose power, which isn't a good thing. With a bit of creative wiring, or an additional part, this issue could be taken care of quite easily.

That also solves the problem of the computer suddenly losing power when the ignition is cut. A hardware and software combination allows the computer to sense when the main power source has been cut and use the remaining power to safely shut the PC down.

The inverter, on the other hand, provides standard household current so that normal power supplies can be used. The chief disadvantage is efficiency. An inverter consumes more power and exudes more waste heat than an equivalent DC-DC power supply.

Basic features

(these are available in off the shelf systems)

NOTE: Some of the features/ideas below may be illegal to run while a vehicle is in operation.

• Play music from CDs, hard drive (MP3s, other compressed files) or external device (USB/PCI FM radio receiver, etc)
• Play video from DVDs, VCDs or from the hard drive (Note: Hard drives are sensitive to vibration, so driving with your carputer turned on may shorten the life of the hard drive. Because laptop (2.5") hard drives are designed for such a portable device, they are generally more tolerant of shock and are an ideal choice over desktop (3.5") hard drives. Laptop hard drives are designed to endure the stress of moving and extreme conditions, unlike that of a desktop hard drive which is usually used as a stationary device, rarely if ever moved.)
• GPS: Provide location tracking, route planning/navigation, etc.
• Satellite radio radio through external receivers. (Both Sirius and XM available)
• Ease of operation through touchscreen display
• Internet browsing through an eligible cell phone or wireless 802.11 connection
• Hands free cell phone control via software with bluetooth
• Other external application support

Intermediate features

• Display video from car mounted camera for backing up. (infrared cameras are available for backing up at night)
• Record video from a webcam/mini-dv camera and store it to the carputer for later perusal. (good for recording close calls on the freeway - setup a rolling buffer which stores the last X minutes on button press)
• Connect with your cars OBD-II interface and display real-time data on all diagnostic information available. (RPM/Temps/Speedo/etc.) Pull error codes immediately. Never wonder what a check-engine light is for again.
• Wardriving: Using your 802.11b or g wireless connection and GPS, locate and log locations of wireless routers.
• Play video games: Run an emulator and have every Atari game. Alternately include actual gaming system in the car.
• Download traffic/weather information from internet. (use home WIFI or connect through mobile phone)
• Connect to a mobile phone or other device using Bluetooth (useful for voice and data comms and synchronizing with PDAs, etc.)
• Interfacing with factory steering wheel buttons or equivalent.
• Provide night vision capability with infrared cameras.
• Wireless synchronization of files between desktop and carputer
• Use broadband internet phone options with cellular data card

Advanced features

• Process video from car in real-time using image recognition software. Capture license plates and store in database with GPS location.
• Using your GPS receiver, store logs of locations vs speed and time of day. This could be uploaded to a collaborative site for predicting travel times vs time of day. (very useful in areas where freeway congestion is variable)
• Provide realtime tracking of vehicle location.

Advantages

• Car computers can provide functions that a stereo system does not, such as internet connectivity.

Disadvantages

• Higher current draw from the car battery compared to a car stereo
• Many hard drives can fail in a car environment

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External links

• Project reports
  • 2004 Association of Computing Machinery magazine article

• Sites
  • Mobile-Effects.com - Global carputer information website
  • Digital Car UK Forums
  • General carputer R&D site
  • Interfacing with BMW's IBUS component control system

• Vendors
  • Custom Carputers
  • The MP3-Car Site
  • Azentek In-Car PCs

• Books about CarPCs
  • Build Your Own Car PC, Ed McGraw-Hill
  • Car PC Hacks, Ed O'Reilly
  • Geek My Ride: Build the Ultimate Tech Rod, Ed John Wiley & Sons

References

• • The MP3-Car Site - Pre 2000 website. Global info forum, largest member following on the Internet
  • Mobile-Effects.com - Originally created 2004, info in website format

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