Carputer V2

ProjectsPublished February 26, 2010 at 12:03 am No Comments

A followup the Carputer V1, this project was started with the intention of putting a more powerful device into my car. The idea of this was not about cost savings; but rather to have incredible flexibility for the device. While the current build of the device is really used for music and GPS navigation, other potential devices like taking video from a web cam and displaying diagnostics from a Megasquirt fuel injection computer were one of the possible uses that motivated the project. Besides, it makes a pretty interesting conversation piece.

background

Car computers are nothing new. It seems that they are actually a dying concept now that the capabilities of GPS units now often include the ability to play music; nevertheless I didn’t want a pre-made solution where everything worked. Unlike the V1 of this project, I wasn’t going to hack some system; I plan to use a real windows PC. The first reason for this was that unlike in V1 of the project, I would not be trying to break any new ground; increasing the chances of success. Using the resources at Mini-box.com and at MP3Car.com, it was pretty easy to piece together a system that could very simply be placed into a car and should work pretty well from the start. Looking into the different form factors of hardware was one of the hardest decisions to make. If I were to start over; I would consider investing in the smallest form factor out there: the Pico ITX PC. Unfortunately, at the time of this writing I am a student and thus on a bit of a budget. For that reason I chose some of cheapest hardware that I could buy.

the hardware

motherboard/CPU/memory

When looking at the options out there for making a Mini-PC of any kind; at the time of this writing VIA seems to have the market in a tough spot. Thanks to the “netbook”, that is changing pretty fast. Intel has poured their energy into some pretty impressive low voltage hardware that they are willing to sell for pretty cheap. Thanks to Newegg.com we can pick up a really basic Intel motherboard with a single core Celeron already on it (with a heat sink) for the paltry price of $70. This is about half the price of a VIA setup.

Called the Intel Little Valley motherboard, its a mini ITX board, meaning that it measures 10cm on a side. Right after I made this purchase, another version that was fan-less was released. I don’t think there are advantages to one version over the other unless space is a concern. The heat sink has the greatest height of any of the components on the board. To make life easy, I just grabbed a single 2gb stick of RAM to use as memory. I am sure that everything would have run just as well on 1gb; but since RAM is very cheap, I saw no reason not to step up to double the RAM. The board also only has a single DIMM slot; so its not expandable later. At 18.99 from Newegg.com; the cost of the RAM was pretty negligible.

power supply

When it comes to power supplies, there are not a lot of choices if you want a solution that will just work out of the box. The best place to get them is a retailer/manufacturer @ www.mini-box.com. Mini-box has a whole line of PSUs that are meant to run off the dirty 12volts that are in your car. The units are meant to accept a wide range of voltage (6v-24v) so as to deal with the voltage fluctuations caused by cranking the car. Because I wanted to preserve the flexibility on install, I chose the smallest of the units. Called the M3 Pico-PSU, it can supply more than the needed amount of wattage for a ultra low voltage CPU like the one used on the Little Valley board.

One of these types of power supply units is probably a must. Using one of these is much more efficient that using an inverter and than an AC power brick and it includes other features like auto turn on and off with ignition and protection against the the thump effect that can be caused by car audio equipment. This component set me back about $80.

display

There are a lot of display choices out there, but the general consensus is that the best touch screens for the dollar are those from Xenarc. That doesn’t mean they come cheap. The screen was by far the most expensive part of my  system. The screen that I chose to use was the lowest model that Xenarc offers. The 705TSV.  It is  a 7 inch resistive touchscreen. The benefit to going for this model over others is that its LED back lit and therefore consumes about half the wattage of the other more expensive models. At ~8w of consumption, we are really nitpicking in terms of power, but I planned to use as much existing wiring as possible; and I did not want to stress the wiring of a nearly 20 year old car (its all pretty high gauge).

Shown above, the screen is nice and black which should match the trim of my car pretty nicely. The screen turns out to be really really bright and is only hard to see when there is direct sunglight on it. Its pretty high quality, but one of the nice things about the screen is that video cable and the USB interface are in one cable which will make the running of the cables pretty easy. I got this for a steal at $210.

the storage

I could have opted for an automotive grade HD, a boot from CF and host of other more exotic options. However I figured that shock mounting a regular laptop HD would do just fine. Having already had a 60gb hard drive lying round; it was no brainier to simply use it. To interface it with a board it also needed to be IDE. Newer versions of the Little Valley board have SATA ports; but to use an IDE drive I needed to get an adapter to the laptop spec IDE which included power. Luckily, being the nerd that I am I had some of those lying around too.

gps

The GPS hardware being used currently is just a basic USB GPS. its installed using the driver it came with. Like most other USB GPS devices…its actually a serial device with a USB converter. This means that in the Windows device manager, it shows up as a serial device. To make detection easier and to make sure that things stay consistent, I would recommend assigning the GPS a static COM port and manually setting that in the GPS software.

the software

operating system

I love Linux as much as the average nerd does. I pay homage to the gods that delivered Ubuntu to us…but in terms of a car PC you pretty much have to run Windows unless you really want to write your own front end and GPS software. If you have to run Windows, it pretty much has to be XP. If you have the resources, XP embedded is nice but a lot of work. Because I wanted to make things as easy on myself I installed a copy of Windows XP for Legacy PC’s. Its light and with a little work you can get all of the little things you need to be installed. One of those was a custom Bluetooth stack; but since the standard Windows stack is hardly functional; I suggest getting the stack recommended by the manufacturer of your dongle. The same can be said for the drivers of any other devices you install. Its not hard as long as you set up the machine in a simulated environment first.

front end

Most car PC GUI’s are really ugly. The RoadRunner interface is one of the most functional with plug-ins for all sorts of cool features. Coupled with a Skin/Add-on package called LSXVOID, it becomes beautiful-ish too. You get inertial scrolling as part of the package. And the software is all free too. Its a pretty win/win. I would tell you where to get the software; but a google search will point you to better results as many of the downloads for the newest versions of the software were found on forums. There aren’t any real tricky configuration options either. A few things to keep in mind. Depending on what GPS software you decide to use and what media player you use, you will need to make sure that RoadRunner is configured to use those applications, otherwise things could become more than a little tricky. Also its important to have a newer version of flash installed in order to get the full use of the LSXVOID add-on. Inertial scrolling had some issues for me at first due to having a crippled, old version of flash installed which was needed because of a driver issue. Once I took care of the driver issue and upgraded flash…all of the problems simply went away.

gps

GPS software is tricky. I-Guidance software is not the best out there; but it has an automotive mode and has has integration directly into the RoadRunner software package; features that made it the most attractive option to me. Its pretty easy to install. Nothing special. Configuring the GPS was pretty easy too. The software works well. To make sure that the GPS is detected after hibernation, assign the GPS hardware a static com port and in the GPS menu in I-Guidance, do not let the software auto detect. Tell it exactly what COM port the GPS device will be on.

media

I am not a big fan of WinAmp; but it is the media software that best integrates with the RoadRunner UI. Given that the UI concerns top anything else since I did not want to write my own UI…I just ran with it. It works fine. Exporting Itunes play-lists are a pain (send them to Windows Media Player first) but it can be done.

Installation

In my cast, I just put the components in my glove box, taking power right off the terminal block located just on the other side of firewall in the engine bay. That is the primary power for the system. The on/off is keyed off the ignition via the power supply. To play music, I also had to replace the stock stereo (it needed it badly) so that I could have an aux input. The ground is run to the chassis ground used for the car alarm (also just on the other side of the firewall. Making my job easier is the fact that the ECU for the car sits right above the glove box, so places to run the wire through the firewall were already in place.

For now, I am calling it done!

Other Notes

I was going add up all the costs and post them…and even though I spreadsheeted everything down the screws that I used…most of those details really aren’t useful to anyone else since they are highly vehicle and install specific.

I chose a Sony stero because the lighting matched my interior and because I could keep using the CD changer that was installed on the car at least 15 years ago.