My In-Dash Car PC project

Well since I installed my In-Dash motorized GL701-NPCT Lilliput screen I thought I would go ahead and get this topic started.

What I want to have in my car is a computer that can dual boot Linux and Windows XP ( Maybe also boot OSX86 ) This will have to coexist with my Can-View. In order to do this I will need a VGA/USB switch. This should be the only hard part of the project.

I have tested disconcerting and reconnecting both the Can-View and my laptop and they both work exactly like I want. When the Can-Views USB and VGA are disconnected the screen stays put but keeps updating like nothing happened. Windows just sees the USB screen come and go and has no problem with it and keeps on crunching bits like any other normal PC. The screen seems to adjust to the resolution settings of the Can-View and the laptop when switching. I thought this would be a problem since I had to strech the screen for the Can-View but when I switch to my laptop the screen displayed every pixel.

I'm guessing most of my questions will have answers over at http://www.mp3car.com

[edit] 07-05-30

Parts...

1. OPUS Mini-ITX Vehicle PC Case w/ built in 120w power supply

2. Jetway C7 2.0 GHz Mini ITX Motherboard (J7F2WE2G-OC-PB)

3. Jetway PCMCIA/CF Card Daughterboard (pcmcia-daughterboard)

4. Built in USB WiFi A/B/G/BlueTooth. Wifi will soon be external for better signal.

5. TWO 120GB Toshiba 2.5inch SATA Hard Drive MK1234GSX (MCS-TOS120)
for raid 1 mirrored.

6. 1GB/1024MB Kingston DDR2 PC 4200/533MHz (KVR533D2N4/1G)

7. USB SiRF III GPS Receiver (usb_sirf_iii)

8. 4 Port USB Hub

9. Mini-Key USB Keyboard DGPN-570

10. 4 port USB surveillance camera DVR to record front and rear cameras when I want to

11. WinTV-HVR-950

12. Slot load DVD burner. Reads everything including RAM burns everything except RAM.


Parts I will need to make...

I made USB/VGA switch. Read further for more info.

I will need to find a boot manager that is compatible with my touch screen so I can select my OS when the computer starts. I have a few ideas that may be used as a work around.

I think I will make a boot CD for my dual boot. for an example...

No CD = instant XP boot
Linux CD = instant Linux boot
Mac OSX CD = instant Mac OSX. Dont know if this will be possible but I'm going to try.

Here is a crappy drawing I made with the touch screen driver config utility



Windows XP running perfectly at 800x480



Here is my current boot manager. I could not go into my Linux install because the resolution is set to the laptops native and the touch screen would not support it. I could have edited the x86config file to allow for 800x480 but there is no point in doing that right now anyway.

 

<div class='quotetop'>QUOTE(Presto @ Jan 10 2007, 05:18 PM) [snapback]373814[/snapback]</div>

I originally wanted to copy your cousin and get the DWW-7VGA screen so it would fit nicely in the map slot. But with the new Can-View allowing for a Lilliput screen I just had to try an in dash Lilliput motorized screen to see if it worked. It did so now I'm going to have the two things I really wanted.

This screen does stick out about a little less that an inch I think. I could have pushed it back about a quarter to a half an inch but that would mean the screen would hit the radio and be at a 90 degree angle. I have found this was a wise decision since the glare from the side windows in the day reflects off the LCD when its at a 90 degree angle and makes it imposable to see. With it sticking out a little I'm able to tilt the screen back a few more degrees eliminating the glare. The only small down side is that you cant swivel the screen. That would also help with the glare but so far I'm happy with it.



Here are some pictures and some very crappy drawings I did to give you an idea of the mods I had to do to get the screen to fit.


Here is what the top view looks like. I put black electrical tape around it to cover up the ugly gray metal case.



Side View



Bottom view. Here you can see my tape and the color of the case



This is a <strike>rough</strike> BAD drawing of the plastic face for the map box. There is a small angle at the bottom of the opening. ( this is in RED )Its about .25 of an inch at most. If you cut along this angle this should give you enough height for this screen to fit. You will also have to shave down the sides of the opening.



This is another <strike>rough</strike> BAD drawing of the radio and its brackets. The RED arrows are pointing to the holes used to secure the LCD to the bracket. The holes beside the arrow are the ones used to bold the radio bracket to the car.



Here is yet another <strike>rough </strike> BAD drawing of the rear of the radio/LCD unit. The blue arrows are pointing to the small screws represented as blue dots. The red rectangles represent small plates that have holes drilled in them to allow the small screw to fit through and a larger hole for a bolt to fit though.


If I ever take the radio unit out again I promise to get pictures.

 

I did buy a USB/VGA 2 port switch to try out. I thought it might work but after playing with it I could not get it to switch between the Can-View and the PC. Also when I had it on the Can-View the Can-View would not accept any input from the screen. It looks like none of the switches I found will work because of the keyboard/mouse emulation screws up the screen input as well as the Can-View. If there is a switch out there that does not emulate the keyboard/mouse please let me know and I will give it a try if the price is low.

It looks like I will be building another switch for this project. <_<

 

Well after looking at my options it looks like I will build a USB/VGA switch. I will use the same approach as my anytime front/rear camera switch. I will use 3 4PDT relays for the USB and VGA wires. I will post a schematic when I get the bugs worked out.

 

First draft of the schematic. I dont know if this will work yet so I would like some input from some electronics geeks out there. I'm just going by what I know and would like some input if you have any.

I decided to use what I have on hand and or what I can easily get a hold of. This includes 2N3904 transistors and 4PDT relays. The relay is 5v, the coil is 62.5Ohm and requires about 80mA. I threw in a 2.2K base resistor because I think that should be plenty to drive all three darlington pair transistors. I'm not to sure on that but from what I calculated it should pass enough current to power the transistors. Thats given the 4017 can source about 1mA.

If you see any problems with my design speak now or STFU! :lol: Just kidding on the STFU. I will be ordering parts soon so I would like some input if you have any so I can change my order list if needed.

 

I ordered all the supplies needed for my switch today. As soon as I get the switch working I hope to start gathering parts for the computer.

I dont think I will have it finished for Hybridfest but I will try my best to finish it.

 

The old version of the motorized screen is crap. The gears would break because they were made of cheap plastic. As far as I know this problem has been fixed with the newer screens. I have not had any problems yet and from what I have read the screen usually breaks with in the first month or two. I've had mine since the beginning of the year and its still working great. If you do go with the motorized Lilliput make sure you get a new one with the round button on the right hand side like mine. The older ones had a triangle button on the right. Stay away from those.

 

I got my parts in today for the switch.

I'm finished with the bread board layout and everything works like it should. I should note that since the VGA adapter boards only use 6 pins I will be using two 4PDT relays and one DPDT relay to save a little space.

VGA adapter boards were bought at http://www.knjn.com/ShopAdapterBoards.html

All other parts were bought at http://www.digikey.com or http://www.jameco.com

The VGA adapter boards allow the DB15-HD to fit the normal bread board or project board hole spacing. I went this route because soldering wires directly to the project board for VGA would be a PITA. Plus you would have 3 big wires coming out of the box for the VGA signal. I wanted a more compact design that you could plug your cables into it and buying these adapter boards was the only easy way to do that. Other wise I would have to etch my own board and drill holes. I just don't want to do that right now.

Every thing works like it should but tomorrow I will be installing the USB and VGA parts to the bread board. I will then give it a trial run with two computers, monitor and USB mouse. The two computer will simulate the can-view and the car PC. The monitor will simulate the indash screen, and the USB mouse will simulate the USB touch interface. I don't see why this wont work since the relays are switching but you never know.

Here is a pic of the current breadboard fully functional. I put LEDs on the relays to see if they were actually switching and they will be removed for the final design.

 

I've now tested everything out. The USB switches just like it should as well as the VGA signal. The VGA signal was a little dirty but I expect that to be cleaned up a little when I get everything on a project board.

I made a small design change. The transistors were getting very hot with the 2.2k resister. I replaced it with a 39K resistor and they seem to keep very cool while still switching on the relays.

Now I got to work on a project board design.

[edit] I should note the VGA adapters had very very small tiny eitty bitty resistors on the RGBHV lines. I removed them to make sure I got a nice clean signal. I think these adapter boards were meant for some kind of other project that requires resistors.

 

I decided to separate the power/switching circuit and the relay/connector board into two different project boards. I did it this way because I did not think I could cram all the stuff onto one board. I probably could have but it would have taken me weeks to organize the traces to a small compact form. So I just decided to take the easy way out and put them on two separate boards linked with a 5 pin wire harness. 4 wires are actually used. I figure doing it this way may also help keep out any interference that might screw up the USB and VGA signals.

I also updated my schematic above to reflect the new changes.

Here is board number one finished, tested, and working like it should. This board includes the power supply and the switching circuit.

 

Board number two built and bench tested. Tomorrow I will give it a trial run in the Prius.

If everything works like it should I will be putting them in their project boxes.

[edit] I added a pic of the back of the of the connector board just so you know what it looks like. I'm not adding one for the power supply/switching circuit because its basically just like my other video switcher for my anytime front/rear camera. If you want to see what that circuit looks like you can just look up my topic on the anytime front and rear camera because its basically the same thing..

 

Just finished testing it out in my car. It works just like it should!

I seen no interference in the video signal. That does not mean there wont be on when I finish the install. I still have to run a VGA cable from the rear of the car to the front. The longer the cable the more signal loss you will have. I'm confident that the low bandwidth resolution 800x480 signal will hold strong on the finished installation.

Now I'm looking into buying the actual PC. I still dont know how I'm going to turn the thing on. I dont relly know what kind of button(s) to buy and where to install them yet. I still have plenty of time to figure that out though. Only about 50 days left until Hybridfest. I doubt I will get it finished by then but I'm still trying my best.

 

Thanks for that info Presto. I still think I want to choose when the PC boots so I will still need to find a button and a place to put it. I'm currently thinking somewhere under or beside the screen.

I now have the switch all finished and in the project box. The two boxes are held together with velcro with a sticky back. The linking cable has a quick disconnect for easily disconnecting the switch in case it needs repaired.

This is the VGA side and you can see the power cables on the right hanging out.


This is the USB side. The USB ports are recessed back into the case. You can see the linking cable on the left. This cable only provides power to the relays.