geegala

spec :

Display & radio
Headunit JVC avx800

power supply
M2-ATX

PC
p4 2.4 GHZ cpu (old pc)
2x512MB ddr (266MHZ) (old pc)
usb touch screen controller (ebay)
perspex case (cut-to-size)
scanconverter (ebay, brand name is grand hand view)
case fansx2 (old pc)
laptop harddrive 120G+adapter (75 computer shop)
4pdt relay

I have this JVC unit for more than a year(warranty expired), so I decided to pull it apart and went ahead to connect it to a car PC. To be honest, if I didn't have the avx800 I would have got myself a true VGA screen like Linitx.
The screen resolution is bearable, but not true vga quality. This project is pretty much completed, but theres room for improvement -- to change the screen of the jvc unit to a true vga screen. The hardest part of the project
was building the case for the carpc, the space under the passenger seat in a golf is just enough to fit a atx motherboard, but its the metal part under the motorised seat thatz made it hard to get the right case(as can be seen in one of the pics, I have to cut it to a L-shape).

The original carpc was a miniITX 1 Ghz, it was too slow in my opinion.

some of the pics were taken in an underground parking lot, so quality isn't great.

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chrislamb

Smart!

__________________
MINI COOPER S PRO

slickdeville

Nice setup.I have a avx810 and am curious how you control the pc?The unit is a touchscreen but not while the pc is on??

geegala

I control the pc using the jvc screen as well, a 4pdt relay let me switch between pc operation and headunit functions.

I disassembled the lcd case(8 small screws, detach the main flex cable, then u have access to the controller board). There's a 4 pin flex cable for the touchscreen , I detached it from the socket and connect to a relay then to an external usb controller, and the controller connects to the pc.

Another reason why i pulled the headunit apart --- the jvc AVX800 unit i have does not have a remote input jack(researched on the internet and found that the not all versions of the jvc unit come with the a/v i/o wire with the remote input jack), so i wasn't able to use the steering wheel buttons to control the unit. New cable costs around 80USD and may/may not need a firmware upgrade as well.

If the screen dies, I will replace it with a true vga lcd and turn it into a jvc vga headunit. Thats my next project.

slickdeville

Cheers for the info.I only have my unit for a week so not too sure if I'am willing to void the warranty yet.I had this unit http://www.cartft.com/catalog/il/729 but it only lasted 3 weeks before it started to act funny.Should have it back from the manufacturer next week but dont know if I'll install it again.

geegala

guess we just have to wait for the big brands to come up with good vga headunits, or wait for the smaller brands to comeup with quality ones. Lets hope your CID650 replacement works up to expectation. The CID650 looks pretty good

tarheel_600

Nice setup! I have the exact same headunit and i would like to hook my laptop to it and be able to control everything from the touch screen like you have done. I have no idea where to start. My laptop has vga and hdmi output. Could you go into more detail on how to do the whole thing? Will i be able to make it work with the vga? Im good with electronics and im not afraid to open the headunit. Thanks for the help in advance!

geegala

http://www.mp3car.com/vbulletin/faq-...l-your-pc.html
http://www.mp3car.com/vbulletin/show...tegration.html

u'll need : a usb touchscreen controller(4-wire!! coz JVC uses 4-wire), a relay(4pdt), a scan converter, flex connectors/, flex extension connector,some small awg wires, soldering iron, some non conductive glue and a pair of steady hands.

The above links are the ones that i have used as references, once you pressed open on the JVC headunit(or if you don't have 12v power, theres a wheel/dial down the bottom of the unit which you can turn to open/close), then you have access to the screws holding the plastics, which secures the main flex ribbon cable. THen carefully unplug one end of the flex cable, thats one screw holding the hinges together, unscrew that and you should be able to gain access to the pcb behind the lcd. Be super cautious with the little flex cables and connectors down the bottom of the pcb, be gentle and don't twist the flex cables.

The blue 4 pin flex is the one that connects to the touchscreen controller on the PCB. Don't put all the screws back until you have tested everything. The hardest part is finding the right flex connectors.

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tarheel_600

so all im doing is taking the four wires in the flex cable going to the touch screen now and putting them through the NC contacts on the relay. then i hook up the scan converter to the vga on the computer. then from there it goes out to the usb touchscreen controller then out of that and through the NO contacts of the relay then to the touchscreen? i've never dealt with either the scan converter or the usb controller. would those two just hook together easily? or do i need to do some splicing there? everything seems pretty straight forward, not terribly complicated. and just by doing these steps my touchscreen will work my laptop?? im good with electronics but my experience with computer hardware is lacking so i apologize for the ignorance. also how is the quality of the picture? is it worth doing? from what i can tell in the pics its look decent. thanks!!! if you had the links to the items you bought that would be awesome also.

tarheel_600

ok. after some research it looks like the usb touchscreen controller hooks up to the touch screen and the other side goes into the usb port on the computer. and for the scan converter one side goes to the vga on my computer and the other side plugs into the red, yellow, white cables going to the headunit. am i correct with all of this?? so to get it to work i would have to go to AV input on the headunit then turn on the relay to switch over the touch screen to control the computer?

geegala

I was without internet for a few days, sorry for the late reply.
yes the usb controller has x+ x- y+ y- as inputs and usb as the output. the scan converter i used has only the video (rca yellow) and a second vga outputs. so the scan converter takes the vga signal and output composite signal(the yellow rca connector). I left the relay nc for touchscreen to work with the headunit, and switch over to computer by applying 12v to the relay.
I have come across a few articles on the forum about a protection diode across the relay coil, I have connected mine with one and I c no difference.
theres a tiny gap on the headunit(when the display panel is in the opened position) where you can pass the wires to the relay . I put the relay in glovebox on the passenger side, the wires I used are usb cables(good insulation with 4 wires) perfect for the job.

The quality is no way near the quality of a true vga lcd, the resolution i am using is 640*480. The navigation using centrafuse is good to my expectation, but for web browsing and text processing, the texts are hard to read. Some had luck using powerstrips (software) to strip down the resolution so the fine text is more readable. It all comes down to what are you going to need the lcd for, for me I can use it to watch tv (with a usb tv tuner) and navigation/weather and
media player, but not for browsing.

Blastman

Hi,
First of all, sorry for my poor English, I try to explain my idea and problem.
I'm making a carputer with my headunit JVC AVX810 and old PC.
The video and audio signals are sended OK, but the only thing that we need is to control te PC with the touch screen of avx810.

I think it's similar of your job, but the avx810 model has extraible frontal.
I've service and schematic manuals of JVC and I localized in front board panel, 4 solded points that are for x+, x-, y+ and y-.

And finally the problem and question:

I can't do the same that you make because extraible frontal can't have any cable hanging on.

The possible solution is localize inside head unit (in motherboard) the 4 signals of touchable interface, but I don't know where are placed (I think that there aren't explicit connections for these).
The touchable front panel and the headunit are connected through 2 "¿ pinout boxes?". ¿These is the only way to know how are sended the signal from frontal to main unit?¿How?.

¿Are there some way to send signal touch to pc?(I know to need usb touch controller)
¿What can I do to extract the signal from Headunit?

Thanks in advance.

geegala

I do think that the avx800 is pretty similar to that of avx810, if you can send me pics of what you have in hand then I can look into it and find out the differences, if any. I have actually abandoned this project since I got my hands on a True Xenarc vga monitor for $230, so a true carpc is on its way... also working on a badge camera for my car

Blastman

I buy the headunit recently, and the possibility of sell it and buy a Xenarc isn't possible for me.
Here you have some photos and printed circuits of the avx810 with detachable monitor.
The rigth flex of open monitor photo has the coordinates (x,y) it has 4 wires, but then I don't know how to take signal from another part of the unit (not take inside of detachable panel).
If you need mor info I've all the schema of the unit.
Thanks.

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geegala

speaking from personal experience, you would have to consider :

the touchscreen overlay's output are resistance values... you cannot have both the usb controller and the onboard jvc touch controller circuitry connected at the same time.

the next part is choosing where to intercept the "signal"

Option I
going thru the non detachable side of the unit ... you will be working with a "processed signal"... hence a circuit to reverse the processed signal is needed, if you are good with electronics, this way gives u a "stealth" installation. I found it tougher to work inside the main unit.

Option II
going with the "raw signal" (intercepting at the touch overlay output connector), this signal can be used by both usb controller & jvc touch controller (one at a time). one advantage of that is-- there is no need to build a new circuit to "reverse" the processed signal. the other advantage is you don't need to tamper/solder the pcb(so it is possible to retain the warranty)... the disadvantage is the "not so stealth installation". ( u will need to make use of a detachable connector)

It is very important to consider:
1 the risks involved
2 time needed and
3 your desire for perfection.

I went with option II, much simpler... by the look of your pics, the avx810 is much easier to work with... and less prone to flex cable failure...

p.s. the letters on the pics are barely readable... and the circuit diagram is not complete...

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