Monday, August 31, 2009
The power supply for a car pc is a little bit different than a standard ATX AC/DC power supply in a home computer. Since your car's electrical system is 12V DC, there is no need to convert from AC obviously. So the M2-ATX is a DC power supply that takes the 12V from your car and feeds it to your computer. All of this is straight forward. The "unknown" part to me was the additional shutdown logic in the M2-ATX.
One of the obsticles in running a pc in your car is that there is some amount of time needed for a proper windows shutdown. In your home, when you turn off your computer, typically you don't just pull the plug. Usually you either shutdown through Windows, or your power button on your computer is configured to send the proper shutdown signal to your computer so that Windows can shutdown elegently.
This is no different in a car pc. When you turn off your ignition, the M2-ATX has some logic that allows for your computer to shut down cleanly. This logic is configurable via some jumper settings on the power supply. Basically you can set your power supply to send the shutdown signal, then wait for a configurable amount of time before cutting the power to your computer, so as not to drain your car battery.
Now, when I first connected the M2-ATX to my motherboard, I connected the J8 on the power supply to the power switch pin header on my motherboard. This allows the M2-ATX to power the computer on and off. Then I connected my case switch to J9 on the M2-ATX. This is to allow me to turn the computer on and off with the case power switch as an option instead of the cars ignition.
In the manual for the M2-ATX it states that you should not jumper any of the J10 pins if you want to use the psu in standard mode. So I hooked it up this way since I wasn't planning on using the pc in the car just yet. What I found was that the power supply would not turn on. There are three posts on the power supply for prividing a power input. POS, IGN, and NEG. Where IGN is for switched power (ignition). I had initially misunderstood the manual for the M2-ATX. In order to use the M2-atx in standard psu mode, you should only connect the POS and NEG terminals, since you won't be using the timing logic. Alternativly, you could jumper J10a which is the recommended mode and connected POS,IGN and NEG. By doing this, your case power switch emulates your cars ignition. Once Chris over at www.mo-co-so.com straightened me out on this, everything powered on and came to life!
One thing to note about the J8 and J9 pins on the M2-ATX. Some question was raised about polarity. It seems the consensus is that there is no polarity on these jumpers. Here is a photo of how my J8&J9 are connected and it is working fine. J8 is on the left, J9 on the right.
Here are a few more pictures of my setup so far. I'm hoping the hi-res photos will be helpful for others at this stage.
Saturday, August 29, 2009
Good shot of the overall computer
Here you can see the hard drive mounted under the power supply
Here is one of the I/O for the motherboard
Finally here is one of the I/O backplate on the case
I've started collecting the various parts needed for this project. Here is what I have and where I got it.
Motherboard/CPU: Zotac Ion from Mobile Computing Solutions
Power Supply: M2-ATX from Mobile Computing Solutions
Power Supply Adaptor: M1/M2/M3 Adaptor from Mobile Computing Solutions
AC/DC Switching Power Adaptor: AC/DC Switching Power Adaptor from Mobile Computing Solutions
Power wiring harness: 6 Pin Wiring Harness from Mobile Computing Solutions
Case: 4th Gen case from Mobile Computing Solutions
HD: 400Gig WD 2.5" Scorpio Blue from Tigerdirect
Sirius: SCC1 + MJS usb adaptor from a guy on mp3car forum
Ram: OCZ Platinum 2gig kit from rbc computing
Tuesday, July 7, 2009
I think this is the area where I have the most options. I haven't set a budget on my project (bad idea) but for the most part the cost variation is minimal except for screens and amplifiers. The screen in a car PC is basically fundamental. It acts not only as the display to your computer, but also as the interface. Here are my requirements for a screen.
- Can be fitted in my double din dash opening
- 1024x768 resolution
- usable in sunlight
Given these requirements, the options may not be so many. Here are some popular choices I've come across.
Both screens have a double DIN housing, and LED backlight for greater range of brightness. Both support resolution up to 1024x768. The 629 seems to be a little bit brighter.
Saturday, July 4, 2009
Powering a computer that is intended to run off your 12V battery in your car requires a different type of power supply than the one you would use in your home computer. Computers use DC power and home computers use an AC-DC power supply to convert from your AC home outlets. Since your car uses DC power already, no need to convert. So for a car PC you need a DC-DC power supply. Since this is a very specialized computer that doesn't have the same power requirements as your home pc, you don't need as much power to run it.
Wednesday, June 24, 2009
- Fits a mini-itx motherboard
- Compatible with your power supply
- Fairly durable
Probably most any mini-itx case would work fine as long as it has a spot to mount the power supply, but I narrowed my search to cases designed specificaly for car PC's.
The case that stands out to me to be the best choice is from a company called Mo-Co-So. The 4th gen Mini ITX case is compatible with popular DC-DC power supplies (specifically the M2-ATX) and has built in RCA audio output jacks located away from the power supply to help reduce electricaly interference. It can take 1 slimDVD drive and 1 2.5" HD. I had considered also the VoomPC-2 case, however, I've read that the RCA output jacks are too close to the power supply and cause too much electrical interference. And that's actually in the product description!
Tuesday, June 23, 2009
In my search for a low power consuming hardware, I came across a new platform developed by Nvidia called ION. It's a mini-itx form factor motherboard with GF9400M video on board and takes either a single or dual core Intel Atom CPU. The first company to sell just the motherboard is Zotac. There are a few different packages to chose from, but this one looks like the best choice for a car PC.
Onboard Video GeForce 9400M
Onboard Audio 5.1
CPU Socket 441-ball
FSB 533 MHz
Dimensions 6.7" x 6.7"
Memory Type DDR2 667/800
Package Contents 3 SATA cable 1 SATA power cable 1 WiFi antenna 1 WiFi bracket
Memory Slots 2×240pin
SATA 3 + 1 eSATA
PCI Express x1 1 (mini)
Form Factor Mini ITX
Video Ports D-Sub + DVI + HDMI
USB 10 (6 on back panel, 4 via pin header)
Power Connector 24 Pin
Looks like this board can be had for about $220 here. Considering the CPU and GPU and Wifi are included and the size and effeciency, it seems pretty reasonable.
Nvidia is claiming to do full 1080p video decoding with this board and I believe it. I have a home media center that I built using a GF9400 and I can do full 1080p with as little as 10% CPU overhead. That is using an AMD 5050e CPU which is faster than the dual core Atom, but not by so much that I would expect the CPU usage in an Atom based system to be that much higher. I'm hoping the CPU usage will still be under 30% when decoding 1080p.
As for mp3's, the dual core Atom is fine. My only concern is how some of the bigger GPS software packages will run on a dual core Atom. I suspect this too will be fine given that most portable GPS units are running on 400mhz ARM CPU's.
You can also get a version of this motherboard with a built in 90W power supply and AC-DC power brick. This would be great for building a tiny media center PC for the home, but for a car, I'm looking more at the DC power supplies with ignition control to manage the system startup/shutdown a little more elegently than just cutting power when you turn off the car.
UPDATE: PCCyber has this board in my area now for less than anywhere else in Canada that I could find!
Here are the requirements for my project. For each item, I list it's priority (low,medium,high) and if it is manditory or optional to the finished project.
- In dash touch screen (high)(manditory)
- mini-itx form factor PC (high)(manditory)
- low power consumption (high)(manditory)
- Sirius Sat. radio control (high)(manditory)
- Playback all common audio/video formats MP3,Divx,h264,etc (high)(manditory)
- Large storage capacity >=250GB (high)(manditory)
- GPS navigation (high)(manditory)
- AM/FM radio (low)(optional)
- Analog/Digital TV tuner (low)(optional)
- Bluetooth hands free (medium)(optional)
- Bluetooth keyboard/mouse (high)(manditory)
- Rearview camera (low)(optional)
- Wifi (high)(optional)
- DVD playback (low)(optional)
- Ipod control (low)(optional)
- Clean professional install (low)(manditory)
I think that is about it for now. Here are some examples of the sort of thing I'm working towards.
In that video, it's a car PC running Windows XP with the Road Runner front end. I haven't looked into the front end enough yet, but Road Runner looks nice, is highly customizable and is under constant development.
I had a look at some of the aftermarket solutions from Clarion and Kenwood. Both look nice, and are priced more reasonably than the myGig system, but still leave no room for customization.
So after much searching I found China. The Chinese are producing very inexpensive car media and navigation units. So inexpensive in fact that it was worth while ordering one and installing it just to try it out. I found a wholesale company called Chinavasion that exports all sorts of wonderful electronics.
Most of the "all-in-one" units sold out of China have the same feature set. I was only looking for double din models to fit my double din (almost) opening in my dash.
- 7" LCD touch screen
- AM/FM radio
- GPS nav
- Aux A/V (my Sirius input)
- Analog or Digital TV
- DVD/Divx/MP3/MP4 playback
- SD card slot
- USB port
I went with this one specifically. Cost me ~$300
I've never installed a car stereo before, so after lots of reading and watching videos, I figured it out for the most part on my own. I was pretty nervous taking the dash on my brand new van apart and digging into the wires, but all told, it really wasn't very difficult. The hardest part was making the new head unit fit in the "double din" opening. As it turns out it may have been 1mm too small. But I "made" it fit. Now I can't get it back out. I'm not too worried. Once I'm ready to replace it, I'll get it out one way or another. ;)
My experience with this head unit has been somewhat of a mixed bag. I'm enjoying it more than my stock radio. However, the old adage, you get what you pay for, fits very well here. This unit is worth $300. That's not to say it's a bad thing. It looks decent. The AM/FM radio works well with decent sound quality. The AUX input works as expected for my Sirius radio. The bluetooth integration is very good. Hands free works fine with my Nokia phone. I haven't tried the TV as I didn't have an antenna to hook up to it. It really isn't a priority. DVD playback was better than I expected. I tested with a Hawksley Workman live DVD. The sound was excellent. By far the best quality sound of all the inputs I've tested. The video looks good, though the screen isn't great in sunlight. You can see enough to control it, but not enough to actually watch a DVD. The SD car slot works, however, the interface to play mp3's is almost unusable. Basically you get 2 windows, on the left a flattened directory structure and on the right the contents of the selected directory. Problem is you only get about 8 characters for each directory or file, so it is very difficult to navigate through your collection. To compond this problem, there is no shuffle or random option.
I haven't been able to get the USB port working. I tried a 2GB USB thumb drive and it didn't recognize it. Then I tried a 400GB WD Passport drive, same problem. Might be very picky about what sort of drive you plug in, fail.
The GPS function actually runs Windows CE 5.0. You put your GPS software on a 2GB sd card and when you select GPS it loads it. It comes with Route 66 which isn't great. And they sent me the European maps instead of North American, so I got rid of R66 quickly. I couldn't get iGO8 to work, but presumably if you had a good copy it would work. I did get TomTom working though and I'm very happy with it. The screen is a good size and TomTom 7 is quite nice. The voice is better than my Magellin unit and the maps/poi's seem as good. The routing also seems to be good.
So, that was my first take on my new car stereo. Took the cheap and easy way out and it's kinda nice. I have my FM radio and my Sirius, but no good way to play mp3's. This isn't sitting well with me. I know I can do better. ;)
Oh one other thing. The opening in the bezel in my van isn't quite big enough for the new head unit. So I can't actually open it to change DVD's without removing the bezel! Not a huge deal for me since I don't use the DVD player, but it also doesn't look perfect. I can live with it for now, but it will slowly rot my brain.
- Ease of install
- Bluetooth works well
- DVD playback is great
- GPS nav works well
- Unusable mp3 interface
- Very little custmization
The install doesn't look perfect, but instead of "finishing" it with this stereo, I've decided to make a longer term plan to replace it with a proper car PC.
We're used to doing a moderate amount of travel throughout the year. Mostly during the summer. We like to do the 6 hour drive to Brantford a couple times a year to visit Maureen's parents and we usually do the 16 hour drive to Halifax to visit my family. When we got Brixton three years ago, it slowed us down a little. When we got Dexter last year, it ground to a halt.
I will admit, it's true what they say about a mini van. It is very comfortable to drive and well we all fit in nicely! We are very happy with our Dodge Grand Caravan.
However, anyone who knows me, knows that I'm not just content to blindly operate my new vehicle/tv/radio/computer/
This is where I'm starting.
2009 Dodge Grand Caravan
Rear overhead DVD/Divx/mp3 player for the kids
Portable sirius radio
Portable magellin GPS
This is where I intend to wind up.
2009 Dodge Grand Caravan
- 7" in dash VGA touch screen
- AM/FM radio
- Sirius Sat. radio
- playback all audio formats (mp3,ogg,wav,etc)
- playback all video formats (mpeg2,mpeg4,h264,divx,etc)
- large capacity hard drive
- gps nav.
- bluetooth hands free
Over the next few months (or however long it takes me) I'll be using this blog as my project worklog.