for anyone who has some experience or expertiese on this subject please help. I am trying to tap into my car navigation system screen which is a 7'' rgbs monitory. has rgb and sync. i have a vga or svideo output on my laptop i want to connect. i have a vga to rgb calbe, not rgbs.
I must admit I'm not 100% clear what you want to achieve.
Do you want to get the output of the car nav system and display on "other" monitor or you want to detach the car nav system and only use the nav's display as external screen for your laptop?
from my research i should be able to use sync on green method for the sync.
VGA outputs r+g+b +vsync + hsync
most screens have input that can take
r+g+b + vsync + hsync
and
r+g with sync (both v and h) +b == called sync on green
there are only few graphich cards that will output sync on green (for examply my old silicon graphics indigo2 have that output)
In order to display sync on green signal on regular monitor you usually do not have to do anything (most of them will read the sync on green signal without problem, in general, I have some 5 CRT and 2 TFT screens at home and they all read sync on green without a problem) but to make sync on green signal from regular vga singnal (r+g+b+hsync+vsync) is bit harder. I was doing that for years as I was using SGI CRT monitor that only has sync on green input as a display for regular PC ...
The adapter can be found on the net and cost ~50$
The adapter can be built, but the ones I tried are easy to build but there are issues:
- you have "ghosts" on the screen
- green is "stronger" then other colors
simplified schematic (that works but not perfectly)
Code:
g+hsync+vsync
100 uF
! !
Green ----! !---------------------------------
-! !+ !
!
680E !
BC548 !
HSync ------------- __---------/\/\------o--------- CSync on Green
\ /!
\ /
---------
!
1k !
VSync ----/\/\----------
g+composite sync
100 uF
! !
Green ----! !---------------------------------
-! !+ !
!
680 ohms !
!
HSync/CSync ------------------------/\/\------o--------- CSync on Green
Here is some app note from maxim about combining comp sync that is relevant to the story, but you should try the simple schematic I provided first before you start anything else.
**broken link removed**
have fun and send us how it went
EDIT:
There is also a input on a monitor that is
r+g+b+composit sync
to get there from VGA output you should do:
Code:
680 ohms
BC548
HSync ------------- __---------/\/\---------------- composite sync
\ /!
\ /
---------
!
1k !
VSync ----/\/\----------