ELEC 242 Lab

Prelude

The Camera

The camera is built around a large block of Delrin with the disk inside (shielded from ambient light) and all the various assemblies mounted to the outside. On the front are the camera lens and the viewer LED.

The back is the "mirror image" of the front, with the viewer lens and the camera photodiode and video amplifier.

The Mechanism

Here is a cross section of what's inside the camera:

The Disk

The disks are produced photographically from computer generated artwork. Here's the disk as it comes from the darkroom:

And here it is cut out and mounted:

The Cable

Because of the number of things on the camera that we need to connect to (the photodiode, the motor, the viewfinder LED, the synchronizer LED, and the synchronizer photodiode) we would run out of jacks if we tried to use phone plug cables to connect to the camera like we have for other external devices. Also, with so many different cables, all looking alike, it would be easy to plug one into the wrong jack, with possibly unpleasant results.

Fortunately, we have a connector with lots of pins that we aren't using: the sound card connector. So we will plug the camera (except for the photodiode output) into it, and reassign the pin numbers. Here are the new pin assignments:

Pin Signal Conn Function Old Function
46 gnd Ground Ground
47 P9 video out microphone
48 -15 V P9 -Vcc for opamp speaker left
49 +15 V P9 +Vcc for opamp speaker right
50 sound_lin_inl P9 sync LED anode line in left
51 sound_lin_inr P9 sync phototransistor collector line in right
52 sound_lin_outl P9 motor + line out left
53 sound_lin_outr P9 motor - line out right
54 gnd Ground Ground