Sunday, 8 July 2012

Oh, what a small screen you have!

I wish developing this cabinet was a full time job rather than having to try and steal an hour here and there. There’s so much I want to do with the Vectrex but oh so little time.
Anyway, although not much progress as taken place in the physical world with respect to the cabinet build I have been busy thinking (again) about the practicalities of a Vectrex based arcade cabinet. In the previous post I mentioned my concerns about the Vectrex display being and looking too small for the cabinet. Well, in fact that wasn’t the first time I had been thinking about that. For a couple of years now I had felt that the Vectrex display would look too small in a full size arcade cabinet and that would be the biggest stumbling block to achieving a realistic arcade cabinet.
I mentioned a long time ago in my Sunday 23rd August news entry that I would ideally want to use a 17" - 19" monitor with the Vectrex.  It would have to be vector based and hence CRT based. Forget about the electronic circuitry changes required to the Vectrex in order to operate it with a larger sized vector monitor (at least one person on the Vectrex forums has claimed to have done this) :- the bigger problem is that I’d been searching for three years and just couldn’t find a vector monitor anywhere.  I did read some years ago about another Vectrex fan that modified his B&W CRT TV to work as a Vectrex vector display. However, I don’t have the knowledge on how to modify a TV and was unable to contact that guy.
So at that time I made an investigation into alternative methods of getting the Vectrex to work with a bigger screen. I came up with something I called the Vectrex Optical Display Engine (VODE) module (you can see it on YouTube).  The VODE simply housed an old 640x480 pixel digital camera operating in video mode and pointing at a standard Vectrex console. This camera was connected to a 22inch TV via its composite input. 

However, I was disappointed with the final result. Not only for the fact that the resulting graphics on the TV were comprised of pixels instead of crystal sharp vector lines, but also because the resolution of the camera was poor. Perhaps, if the camera resolution was significantly higher the results would have been better, but the result would still be less than optimal considering that the TV operates in raster scan mode.

Next, I remembered that in the early days of television, they included lens to make the then small CRT screens appear bigger. I also recalled seeing adverts from the early 90’s where add on lenses could be purchased for TV’s and monitors. I believe it was in 2009 that Vectrex fan DarrlyB experimented with a Fresnel lens to magnify the Vectrex screen. He used a commercialised version of this type of lens which is normally sold as a book reading aid. It’s like a cross between a magnifying glass and a sheet of paper.

 I purchased one of these lenses too to carry out similar experiments. However, this type of lens was less than satisfactory. When you were not directly in front of the lens there was little observable magnification. I found that when I was looking off centre, the spiral structure built into the lens played havoc with the display of the vector graphics. On most of the games there seemed to be some strange prism and line spiralling effects.

Another potential issue is, if I could have a bigger screen, I would also need bigger overlays. Some Vectrex fans like playing games without the overlays, but for me some overlays really do add to the game, take Pole Position, Vectrexians or Vector Pilot for instance. The accompanying overlays for those games really do add the illusion of colour.
So all the above captured thoughts relate to problems, but worry not I have a solution….

No comments:

Post a Comment