Subject: Sega glasses

From: Darren Anthony Mason <[email-masked]>
Date: Fri, 26 Aug 1994 09:15:32 +1000 (EST)

Sorry if this is a FAQ, but I don't have the FAQ at the moment and I've
only got limited time on the net this morning.

Anyway just aquired a pair of Sega 3D glasses and was looking at the
circuits as per described in the book virtual reality creations.

One diagram shows the parallel port with three connection (D3,D4 and GND).

On the diagram showing the interface to the sega interface module I can
only see where D3 connects. Is there a need to connect the D4 to somewhere?

For those without the book D3 is pin 4 and D4 is pin 5.

Any help appreciated

Darren Mason
[email-masked]

---

From: [email-masked] (Jose Daniel Ramos Wey)
Date: Fri, 26 Aug 94 10:11:59 EST

> From [email-masked] Fri Aug 26 04:47:03 1994
> Reply-To: <[email-masked]>
> Date: Fri, 26 Aug 1994 09:15:32 +1000 (EST)
> From: Darren Anthony Mason <[email-masked]>
> Subject: Sega glasses
> To: [email-masked]
> Mime-Version: 1.0
> Content-Type> : > TEXT/PLAIN> ; > charset=US-ASCII> 
> Content-Length: 599
> 

I used another source for the SEGA code: the Virtual Reality Creations' circuit
isn't very clear. I used the circuit from another book. I have a copy in ASCII 
format, included in this e-mail. This description was written by Frank (?),
and I found it ocasionally one day playing around with Internet...
This circuit uses a 2n2222 transistor, that's not included in the circuit on the
VRC book. It only has the conection to the Serial port (RS 232).

Jose Daniel Wey
[email-masked]

--------------------------CUT HERE------------------------------------

Circuit to connect SEGA 3D glasses to RS-232 port.
--------------------------------------------------

       RS-232
     DB25 / DB9
                                                   10K
RTS   4      7  Switching signal +/- 10V  --------vvvvv--+
                                                         |
                                                         |
GND   7      5  Ground ----+-------------+--+---------+--|----+
                           |             |  |         |  |    |
                           |             |  +-|>|--+  |  |    |
                           +--|>|--+    ---        |  |  |    |  Transistor
                                   |    ---  22 uF |  |  |    |   2N2222
                                   |     |         |  |  |  +-+---------+
                                   |     |         |  |  |  | Emitter   |
                                   |     |         |  |  |  |           |
DTR  20      4  Vdd +10V --|>|-----+-----+         +--|--+--+ Base      |
                                         |            |     |           |
                              +--+--+--+-+-vvvvv---+--|-----+ Collector |
                              |  |  |  |    10K    |  |     |           |
                              |  |  |  |           |  |     +-----------+
                      +-------+--+--+--+-----------+--+--+
                      |       1  9  13 14          5  7  |
                      |                                  |
                      |   RCA CD 4030 Quad XOR gate      |
                      |                                  |
                      | 2 11  12       3  6  8   10   4  |
                      +-+--+---+-------+--+--+----+---+--+
                        |  |   |       |  |  |    |   |
                        +--+   |       +--+--+    |   +--- Outside of jack
                           |   |             |    |
                           |   +-vvvvv-+     |    +------- Middle of jack
                           |      22K  |     |
                           |           |     +------------ Centre of jack
                           +-vvvvv-----+     |
                              22K      |     |
                                      ---    |
                              .01 uF  ---    |
                                       |     |
                                       +-----+

Diode:     --|>|--

Resistor:  --vvvvv--

Capacitor:   |
            ---
            ---
             |

This is my best attempt at a rendition of the circuit which connects my
SEGA glasses to my AT. I didn't design the circuit -- I'm a software
rather than hardware person. In fact I barely understand it -- as far as
I can tell, the .01uF capacitor & the 22K resistors act as a delay. The
outputs of the XOR gates feed back into their own inputs, thus producing
an oscillator. The "jack" mentioned in the diagram is the mini-jack
which is connected as standard to the glasses. "Centre", "middle", and
"outside" relate to the external connections, looking at the thing
end-on.

Disclaimer: The circuit diagram above may be entirely wrong. My
description may be wrong.

Caveat emptor... to paraphrase the standard software licence agreement:
It's as good as I can get it. If it doesn't work or blows up your
computer or your glasses and blinds you for life, I'll give you back all
the money you paid me.

Good Luck...    Frank.