28 November 2008

Inside Terminator's eye

Don't panic. After you've seen the optical receiving system, the transmitter will look horrible.

The plate is a CD-ROM player cover, bent upwards to hold a clothes peg. The transmitting LED is loaded there. The 488 Hz tone is generated with the usual XTAL+divider chain that drives a 2N2222A (the metallic cylindrical "thing").

In the center of the board there is a current generator (TO-220 transistor, the white cube, two red LEDs in place of a zener) with a jumper to provide two drive levels.

No tilt/turn controls were mounted since the path didn't require any precise beaming. Moreover the LED has a wide beam, so a simple tilt screw might be enough. No need for micrometric adjustments.