johan's blog

Fan speed control on Epia. Grrr...

As I don't need handson access anymore to the motherboard, I'm assembling everything and puting it in the case I have. Seems somehow safer :-)

It turns out with only 2 fans (CPU and Case) my CarPC already makes a lot of noise. (Imagine two 40mm fans running at 6500rpm in an aluminium case...)

I thought installing lm_sensors and automatically reducing the speed of the fans would take care of it.
But here comes the fun part: It seems the Epia board doesn't support reducing the fan speed!

I thought these boards were designed for low power / low noise environments.

I guess I'll have to find something else to get them running at a lower speed...

AUX in for original head unit

After searching, I finally found what I need: an adapter to attach PC audio to the CD changer interface of my OEM radio.

Connex

It's not cheap, but it should trick the radio into thinking a CD changer is attached.

The reason why I want to keep the original head unit are the following:

- Once removed from the car, the OEM radio becomes prety useless. It won't work in an other car model, and only after invertention from the dealer in other cars of the same make.

FM modulator

It seems I misjudged the way they work...

Until I tested it, I was under the impression the FM-modulator just inserted an audio signal on the defined frequency.
It turns out it also blocks all other frequencies... :-(

I though I could hook up my Car PC with such a modulator and use TA on my radio for traffic announcements, etc...

Now it seems this is impossible and I need to install an extra switch to turn off the FM modulator if I'm to use my radio in an ordinary fashion...

Well, I guess I'l look into convertors to hook up my Car PC to the CD changer input.
Sound quality should be better too, although I'm not complaining about the quality of the FM modulator...

Got software suspend working

Today I got software suspend working.
This was easier as I initially thought. In fact, it's just very easy.

I just followed the tutorial on
http://gentoo-wiki.com/HOWTO_Software_Suspend_v2
and it worked flawlesly!

Here are some timings from my system. All numbers are seconds.
(I'm using compression in the kernel.)

Tested with X running and playing music. (xmms)

Shutdown:

0: Pushed powerbutton
4: Music stopped playing and hiberation started in textmode.
15: Powerdown.

PC is completely shutdown after about 15 seconds.

Booting:

0: Pushed powerbutton
12: Bios stuff done, Kernel begins to boot.

Gentoo base install

I now have a (working) basic gentoo installation.
Feel free to ask questions if you have any.

I used the following /etc/make.com settings:

# For M-10000 Nehemia
CFLAGS="-march=i686 -msse -mmmx -mfpmath=sse -Os -pipe -fomit-frame-pointer"
CHOST="i686-pc-linux-gnu"
CXXFLAGS="${CFLAGS}"

I also made use of the evtouch driver to get the USB touchscreen working:

http://stz-softwaretechnik.com/~ke/touchscreen/evtouch.html
http://linux.chapter7.ch/touchkit/mini-howto.txt

Its not callibrated perfectly, but it's very usable already.

The only problem is the device used in the configuration of X is variable. (I plan to foresee USB ports in the car to temporarily connect things: Keyboard, mouse, digital camera, ...)

Already a setback... :-(

You didn't hear from me any sooner as I experienced a minor setback.

It turned out the RAM I was using developed some errors...
Although I tested it with memtest86 before, it now definately has errors.

The memory is still under warranty and I just started the RMA procedure.
Luckely I have the possibility to borrow some RAM from a normal PC, so I can continue working on a bootable Linux system.

I've tried Fedora Core 5 for a moment, but I was too bloated to be of any real use.

I've settled for Gentoo as I like to work my way up from scratch to a working system and not the other way around to stripping Linux.

The hardware arrived and I have a question.

Almost all hardware is in my possession and I can really start.

Here are the current specs:

Via Epia M10000 motherboard
512MB RAM
80GB HD
VoomPC enclosure
M1-ATX 90W PSU
7" TFT touchscreen (Unknown brand)

Actually all I needed arrived already on Wednesday, but I was too busy with other things so I didn't really start yet.

I ordered from cartft.com (based in Germany, Europe) and these guys are amazing. I ordered and payed on Monday and 3 hours later (after ordering) I got confirmation the goods were already sent. (With tracking ID and everything.)
On wednesday everything arrived, and this was an international shipment!