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RE: On CRT-type camcorder viewfinders and HMDs

> -----Original Message-----
> From:	Tung-Yep, Philip [SMTP:]
> Sent:	Monday, January 08, 2001 2:03 PM
> To:	'Roberto C.'
> Cc:	
> Subject:	RE: On CRT-type camcorder viewfinders and HMDs
> 
> It seems to depend upon the CRT tube, associated circuitry and your scan
> convertor.  I suspect that almost any B&W tube is capable of resolution well
> beyond 640x480 but that the signal gets degraded by poor driver circuitry,
> long wires, crosstalk, cheap scan convertors etc.  My v/f HMD gives an image
> comparable with or better than an M1.  This is despite having come from a
> camcorder which fell two stories and being connected via a cheap scan
> convertor.
	[Simon Wood]  
	Let me guess, the guy couldn't fit everyone in the frame and started to walk backwards..... ;-)

	Have you got any pictures of the HMD posted anywhere? I'll like a look at what's possible.
>  
> > 3.  I suspect that I'll have to add additional circuitry to adapt VGA
> > output of a video card to something that can be handled by the
> > viewfinder.  Any suggestions on circuits that can allow the CRT to
> > handle VGA?  
> > 
> While you could build a scan convertor from components, it is probably going
> to be easier and cheaper to buy.  I use a small (1/4 ISA) cheap board
> designed to allow PC games to be shown on TV.
> 
> There are also some schematics at
> http://www.hut.fi/Misc/Electronics/circuits/vga2tv/composite_adapter.html
> for quick 'n' dirty adaptors but you may have to tweak your SGATextMode or
> modeline settings with these.
	[Simon Wood]  
	Nice and simple circuit. I'm experimenting with something similar to the transistor one, but using a 'RGB' connection to telly to get colour. Need to knock up small circuit to provide power to pin 8 and pin 16 (slow and fast switching) to trigger Scart input on TV.

	I guess with some clever programming and two tubes you could do a stereoscopic HMD.... great for that range finder and targeting system.

	There are X settings here:
	http://wearcam.org/wearhow/tv-x.html

	And I did have some SVGATextMode (PAL) settings somewhere, email me if you need me to dig them out.

	Simon W.

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