Car PC
A car PC or carputer is a PC that is permanently installed in a car or truck , usually with a touch screen for convenient control.
features
Usually, due to the lower power consumption and the extreme conditions in a vehicle (vibrations, heat, cold), components that are intended for notebooks are used. Car PCs are often built into very small housings so that they fit under a seat or in a glove compartment , or they are installed in the spare wheel well or in the trunk.
In order to simplify the control via the touchscreen, special software is often used, with the help of which the individual functions can be controlled. The control relay is made possible by this. So z. B. the window or the heating can be controlled via the PC. It is also possible to read out motor data in order to have the current speed and engine speed displayed on the PC.
Structure of a multimedia car PC
A car PC is an ordinary computer that is built into a car, often based on the small ITX mainboards, sometimes with specialized processors such as the VIA C3 . Furthermore, barebones of notebooks, an ITX variant for Intel Pentium M or normal ATX computers are used.
Image output and input mostly take place via a small touch screen , or via a TFT screen and a mouse. Commercially available 7 "touchscreen monitors usually have a base with which they can be easily attached. For higher demands, individual consoles are manufactured that are tailored directly to the corresponding car. It is advisable to install the monitor in the center console of the vehicle. Many newer vehicles already have a navigation display, an integrated display in the combi-instrument or in the dashboard.These mostly high-resolution original vehicle displays are ideal for the image output of the car PC.
Data storage is often of a notebook hard drive taken, newer models are liquid stored and highly shock resistant, which especially in vehicles with sports or coilovers is very important because these springs very hard and wont to be read or write errors to a complete failure Hard drive can come. For additional protection, the hard drive is hung in a U-profile with a special rubber band construction. A laptop CD / DVD slot-in drive is used in the same way .
Power supply
There is no uniform DC or AC voltage in a vehicle. B. the total on-board voltage due to the high power consumption of the starter to less than 10 V. A special power supply unit is therefore required to ensure smooth operation. The PC does not start up until a few seconds after switching on the ignition. This waiting time is used to ensure that there is enough energy to start the engine. If the ignition is switched off again, the PC will shut down after a period of a few seconds to several hours. However, an operating voltage of 5 V is maintained, which is switched off when the PC is completely switched off in order to avoid problems with the battery, which could arise from the power consumption of the PC even when the PC is switched off.
Input devices
Since keyboard entries are cumbersome using the touchscreen keyboard, a keyboard should be installed. Here, for example, those in laptop format are suitable for server administration. Speech recognition is also a control option.
For cars with a multifunction steering wheel, this can easily be connected to the PC via a relay card. This can be used to define actions for the respective circuit, such as B. changing the music volume. Instead of a multifunction steering wheel, a steering wheel remote control can also be retrofitted, which sends out infrared signals, which in turn can be processed with the appropriate receiver.
Audio system
Most mainboards have an integrated sound card that is sufficient as a basis for a hi-fi system. Additional sound cards, however, enable better sound quality or 7.1-channel mixing, and some offer cinch outputs for lower quality losses. To control the loudspeakers with the audio signal of the sound card, an additional amplifier is required, or a radio or "head unit" with an AUX input.
Useful extensions
An active USB hub is useful for connecting enough extensions , as a passive USB hub draws the voltage via the PC power supply and not directly from the car battery and therefore may not be able to supply enough power.
A GPS mouse determines the position of the vehicle via GPS . It is the heart of a navigation system.
Many newer cell phones have a Bluetooth connection and a Bluetooth USB adapter can be used to network one with the PC. With special software it is z. B. possible to automatically turn down the music for incoming calls and to make calls via a microphone. In addition, you can send text messages via voice recognition or have incoming text messages read out to you. Wireless internet access is made possible with a UMTS or even a narrow-band GSM mobile phone that is connected to the car PC.
A webcam can be used as a reversing camera, which allows the driver to look back through the monitor. Newer cameras even have infrared sensors and can take night vision recordings. This means that this parking aid can also be used at night.
With so-called relay cards, circuits can be controlled from the PC. With this function, the on-board electronics can be controlled remotely, e.g. B. the electric windows or the air conditioning. The relay card can also receive signals to e.g. B. to react to buttons in the vehicle or interrupted circuits, as is the case with defective light bulbs. A special interface called OBD-2 enables access to the vehicle's engine control unit . It is thus possible to carry out diagnostic operations (e.g. temperature monitoring, fuel consumption or performance testing) while driving. In addition, hidden functions of the vehicle can be activated via this interface (e.g. the flashing of the front indicators as in a US vehicle) or the injection maps can be adjusted as is e.g. B. is operated in chip tuning . In addition, reading out the fault memory independently saves unnecessary visits to the workshop.
Data can easily be transferred from the home PC to the car PC and vice versa via LAN, WLAN or a USB stick.
Touchscreen friendly environments
Since a touchscreen only allows rough inputs, a special surface is helpful, which also usually has all the important functions already integrated, such as a media player and often a navigation system. In many cases, the appearance of the surface can be adapted to your own car, some programs change contrast and brightness with a day-night function from a certain time.
An overview of the current interfaces:
- Free / partly open source
- iCT - In Car Terminal
- MediaCar
- CarFlash
- MediaEngine
- cPos - Car PC Operating System
- Road Runner (now known under the name "Ride Runner" to avoid conflicts with registered trademarks)
- Commercially
- CES 4 - Chameleon
- Centrafuse
- Street deck
- artemis-obd 2.2 (Itunes App Wifi OBD2 for Apple iPad)
Market spread
So far, Car-PC have only been offered as an accessory - often even as a kit. One of the first vehicles with a standard Car PC is the Tesla Model S electric sedan, launched in 2012 .
Common areas of application
- Hands-free system: the phone is connected to the PC via Bluetooth
- GPS navigation
- Media center: music ( MP3 , CD), videos, television (e.g. via DVB-T ), radio, pictures
- backup camera
- Vehicle diagnosis via OBD
literature
- Kurt-Jürgen Berger, Michael Braunheim, Eckhard Brennecke: Technology automotive engineering. 1st edition, Verlag Gehlen, Bad Homburg vor der Höhe, 2000, ISBN 3-441-92250-6 .
- Robert Bosch (Ed.): Autoelectronics Autoelectronics. 5th completely revised and expanded edition. Vieweg & Sohn Verlag, Wiesbaden 2007, ISBN 978-3-528-23872-8 .
- Karl-Heinz Dietsche, Thomas Jäger, Robert Bosch GmbH: Automotive pocket book. 25th edition, Friedr. Vieweg & Sohn Verlag, Wiesbaden, 2003, ISBN 3-528-23876-3 .