Recently, I was forced to sell my trusted Ford Probe, because it was getting old and maintaining it became increasingly hard and expensive. It was my first real car that I paid for myself, so parting with it was hard for me. I really wanted to buy a new car that was a worthy replacement for the Probe, and I ended up buying a 2005 Mazda RX-8.


Carputers are something that have interested me for a while, and it's something that comes up with every car I have used and owned. A carputer is basically a low powered computer, built specifically for usage in a car. Functions can range from basic music playing, to running browsers and playing DVDs. There are some comercially available solutions available, notably by Pioneer. But really, when I decide to walk down this road, I want to create one myself.

From what I gathered previously on this subject, you basically need a motherboard with a low-power CPU, a special power supply for car usage and a LCD screen. A touchscreen seems to be the most logical choice, and these are available in abundance from a variety of vendors. The low-power CPU always seemed the most limiting choice, because there weren't really any good options, besides using a Via chipset and CPU, or dishing out lots of cash for a Intel or AMD low-voltage CPU.

Raspberry Pi

In an earlier article I mentioned the Raspberry Pi, a cheap, low-powered, ARM-based board. It basically has the hardware of a cheap Android phone, and has recently been finished. After some recent setbacks, the board seems to be released and on its way to the customers.

I have seen demos of this board running XMBC and decoding Full-HD H.264 content without stutter. This means to me that at least the video decoding capabilities are up to snuff, and I have ordered one just for that purpose. But then I realised that I could probably use the board for more than just a media streamer, and a carputer is one of them.

Mazda RX-8

The Mazda RX-8 is a great car to drive. More refined than the Ford Probe, but just as powerful and just as unique (I haven't seen another one on the road yet). The version I have comes equipped with an integrated radio with in-dash 6 CD changer. Fancy and all, but I used to have a car radio with built-in Bluetooth support, which is something I really miss in the RX-8. The good part is that there are replacement parts for the RX-8, which allow me to remove the integrated radio and replace it with a standard Double DIN holder. This in turn allows me to install an appropriately sized LCD touchscreen, with enough room behind it to stick a Raspberry Pi in.


Below is a simplified schematic of how I think the set-up will work.

Rendering prettier diagram, hold on...
 +--------------+ Ignition |                          |
 |              +----------+ Car Systems              |
 |              |                                     |
 |              +------------*--*---------------------+
 |               Sound System|  :Car Power
 |      +-------------------=+  | (14V Unstable)
 |  +---+-----------------------*---------------------------------+
 |  :   :       +-------------------------------------+           :
 | +++  |       |                                     |           |
 | |5|  |       |                                     *Power------+
 +-*V|  |       |                                     |
   | |  |       |                                     *USB_Touch--+
   |C|  |       |                                     |           |
   |o|  |       |            Touchscreen              *USB_Front--*
   |n|  |       |                                     |           |
   |v|  |       |                                     |           |
   |e|  |       |                                     |           |
   |r|  |       |                                     |           |
   |t|  |       |                                     |           |
   |e|  |       +------------*-------*----------------+           |
   |r|  |                HDMI|        RCA                         |
   +++  |                    :                                    |
    :   |                HDMI|        RCA                         |
    |   |       +------------*-------*----------------+           |
    |   |       |                                     |           |
    |   +--Audio*                                     |           |
    |           |                                     |           |
    *--USB_Power*                                     |           |
    |           |           Raspberry Pi              |           |
    |   Ethernet*                                     |           |
    |           |                                     |           |
    |           +-------\                 +-----------+           |
    |           | Boot  |                 |   GPIO    |           |
    |           |  SD   |                 |  Headers  |           |
    |           +-------+----*-------*----+-----------+           |
    |                    USB1:       :USB2                        |
    *------------------------+-------+-------------=+             |
    |                        |       |              |             |
    |                +-------+-+   +-+-------+      |             |
    +-----------Power+ USB HUB |   | USB HUB +Power-+             |
                     +-*-*-*-*-+   +-*-*-*-*-+                    |
                       : : : :         : : :                      |
      WiFi 11.N Dongle-+ | | |         | +-*--------------------=-+
                         | | |         |
        Bluetooth Dongle-+ | |         | +---+
                           | |         +-+{s}+Disk Storage
                GPS Dongle-+ |           +---+

The Raspberry Pi itself has enough connectors available to connect a LCD touchscreen and hook up to the sound system. With an USB hub or two I also have enough USB ports to connect any dongle I want. I'll also probably want an USB disk or something, because the onboard SD card reader is meant for the bootloader and OS.

What now

All of this is something I thought up the last few weeks whilst driving the RX-8. At this point there are really two points that are stopping me from buying all the parts and doing it:

  • Availability of parts
  • Cost

As mentioned, the Raspberry Pi has only just recently started shipping, and there aren't a lot of people that have one yet. Really, I haven't even received an official order confirmation yet, only a notification that they haven't forgotten about my interest. The so-called replacement head unit is also something that is not readily available, at least not in my case. My RX-8 is equipped with an automatic climate control system, neat. Turns out however that the company that makes there head units is located in the US, and the US version of the RX-8 never got the automatic climate control system, only a manual version. So, the replacement head unit is only compatible with the manual version, not the automatic one in my car. Go figure. These hurdles can be overcome, however.

Availability issues solved still leaves a cost issue. The individual parts themselves are quite expensive. The LCD touchscreen itself is about € 200, a power supply is probably around € 50. The replacement head unit that I found which DOES work with my car, is a whopping € 350, however. If I total everything I need, I'm looking at something around € 750.

For now, I'll just wait until I receive a Raspberry Pi, and go from there. The board itself is interesting enough to play with, and if I'm still as enthusiastic about this project then, I might just restart this project and create something awesome.