Sega12

Connecting the Sega 3D Glasses to the Macintosh Part I, The Hardware Version 1.2, Copyright 1989 Juri Munkki This document describes how I connected the Sega 3D Liquid Crystal Shutter Glasses to my Macintosh II RS-422 port. With the glasses you can use software specifically made to display a stereo pair of images. This method of displaying 3D graphics gives most users a feel of depth in the image. Stereo viewing has interested me for years. I regularly read the usenet rec.games.video newsgroup, since it occasionally contains information on coin-ops. When the Sega Master system was introduced, I read about it and discovered that it can control 3D-glasses. I immediately became interested, but I had trouble finding Sega in Finland. This lead me to post an article in rec.games.video. As it happens, Stan Lackey had already built an interface for his 8-bit Atari computer. With his help, I built an interface that works with the Macintosh. It should work fine with any RS-422 or RS-232 serial port and if you know some electronics, it shouldn't be too hard to modify it to work with other interfaces as well. All my thanks go to Mr. Lackey. Building the circuit requires a certain amount of experience with a soldering iron and I recommend that you verify your circuit with a digital multimeter. You are the only one responsible, if this circuit manages to fry your serial port, your computer or something else. The circuit can be tested without plugging it to the serial port. I recommend that you use a 9V battery and connect it to the inputs that would normally take the TxD+ and TxD- signals. I haven't drawn a circuit board for this project. I simply used a prototyping board and connected the components with wire. Here's the list of components I used: Amount Item Comments 1 CMOS-555 Timer 1 CMOS-4013 D-flip/flop with two inputs 1 CMOS-4070 Quadruple 2-input exclusive or gate 1 Rectifier I just bought one with a low voltage specification 2 0.1 uF capacitors 1 0.01 uF capacitor 2 3 kOhm resistors I used a single 4.7 kOhm trimmer 1 3.5 mm stereo connector A female connector like those in Walkmans. 1 Circle-8 connector A male connector for the Macintosh serial port. 2-4 m wire some shielded cable with 3 wires 1 VERO-board A prototyping board of some sort It is very important that you use CMOS-parts, since the operating voltage is 10 V. We need 10 V, because the glasses use a 400 Hz square wave when they are opaque. When they get 0 V, they are transparent. Below is the circuit that I used. It's probably not optimal (I think it might work even without the 4013, if you changed a few resistor values), but I have built two of them and both work. The one I'm currently using has a trimmer instead of the two resistors. If you are using a trimmer, you might want to use an oscilloscope to verify that you are getting 400 Hz at the output plug or 1600 Hz at the 555 output (Pin 2). I used my Mac II as the oscilloscope. Since the frequency is audible, I was able to dig…