The Nintendo Virtual Boy (TM) contains two Private Eye (TM) -like displays. These have moderate resolution and greyscale. However, they require custom driver chips. Generally hacking such things are not worth it, but at $160 retail for 2 displays, it becomes interesting.
Such displays work by having a column of red LED's with a mirror that vibrates, scanning across the eye. By changing the LED's rapidly in sync with the mirror, a full display is created (through persistence of vision). A great design that has a theoretical limit (from back of the envelope calculations) of about 40,000 pixels (15 micron packing density) by something large (however fast a LED can be switched or the diffraction limit of the optics).
My experience with the robustness of Private Eye tends to bias me towards these displays, even though they tend to charge a fortune (1200$) for something that should be cheap to make (say, $30). Thus, the interest in the Virtual Boy.
Generally these types of displays are driven serially. Thus, there are two ways this game system could be adopted to something useful. First, remove and package the displays and get the general driver chip from Reflection Tech Inc. or Phoenix Group Inc. and see if it can be adopted. Secondly, one could get the developers kit for the Virtual Boy and see if a cartridge could be made that would just provide bitmap access to the display.
To Open: Drill a 15mm dia. hole 5mm deep over the four corner screw holes, the one in back, the one in front, and the two deep ones on top (see Fig. 2 ). Remove the black half of the casing. (see Fig. 3 ) Snap off the long black cylindrical struts and unscrew the focus-slider (see Fig. 4). Pull metal cage up and out of red plastic (see Fig. 5). Unscrew as necessary (see Fig. 6). Should end up with something like Fig. 7).
Thanks to Dana Kirsch for finding a good way to do this compared to my hack and slash.I hacked a letter opener with a dremel and made the appropriate tool for opening the thing in about 10 minutes. After you get it open once, you can slot the screw heads with a dremel cutting wheel and use a standard screwdriver thereafter... The tool is basically a small pin spanner looks like this: xxxxxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxxxx There is a smaller sized screw for the cartridges, so you'll have to make two tools if you also want to be able to open those without marring the package. The driver chip for the vboy is some nintendo custom thing that probably also does the 3d calculations (I would guess that it's got a z-buffer)... Thad> Not enough memory in these units for a z-buffer. I hear the Playstation does not even have the hardware to do this...just software Never having used a private eye, I was pleasantly surprised to see the use of several shades of red. Pity that the 3d chip doesn't use them to anti-alias the lines it draws... That would really kick butt! Thad said that he thought the resolution seemed artificially limited. Is it? Could be a cost-cutting measure in the driver chip. Or maybe that's done intentionally to get the different red-levels without using time division to do it? What is the horizontal scan-rate of one of these things, anyway? Thad> 50.2 Hz on my Private Eye (non-interlaced of course). They only paint going one way (not bidirectional). Haven't strobed the VBoy yet. If you were to drive the thing from a serial port, then the "best" way to do it, I think, would be to treat the thing like a terminal and hack a special cartridge for the unit that has a memory mapped serial port... I have the impression, though, that the chip in the cartridges is not just an ordinary ROM... If you want graphics capability, then use something like the guts of xterm to get both vt102 and tektronics capability... Somewhat less optimal, but probably quicker to hack together, is to use the nintendo driver chip but only one display. This gives you only one head-mounted display per vboy...still an acceptable yield... The computer interface is still an issue. Finally, if you want to use the vboy unit as-is, then the best way to do it is to build a terminal cartidge for the thing... I don't suppose that anyone has thought of getting a developer's kit for the thing? PS: The vboy does stress out your eyes after a while... Is that the artificial stereo vision, or is it intrinsic to using the private eye display? Thad> The Vboy stresses my eyes too, but the Private Eye doesn't. I think it has something to do with vergence and focus rivalry of the binocular display of the Virtual Boy. Kinda odd.Last modified: Mon Dec 4 00:44:54 1995
