How to Pan the Camera

A quick summary: The camera is contained in a self made brace which is superglued to the shaft of a stepper motor which is connected to a circut of 4 transistors which are controlled by the parallel port.

I modified the server program I use for the lamp and it now controls both the lamp and the stepper motor. The lamp required one data line, the motor required 4. Since the motor can be operating while the lamp is on, and since both devices are controlled by the same parallel port, it now became necessary to have a "state" variable which keeps track of which data lines on the parallel port are currently active, so the lamp doesn't get shut off during a motor routine.

Each of the 4 transistors for the motor is triggered by one of the data lines from the parallel port. Each transistor then controls power to one of the 4 stepper motor contacts. Each contact must be given power in sequence to make the motor turn in one direction or another. So, in addition to remembering what the parallel port currently looks like, its also important to remember which contact was touched last. The server controls all of this to make the circutry as simple as possible.

The power driving the motor is a simple 9V DC power source, provided by an AC 9V battery adapter.

The motor is built into a radio shack project box, to give it the required support. The motor was obtained from a dead floppy drive. Floppy drives are wonderful sources of stepper motors and I'm willing to bet you can obtain them for free if you look hard enough. The end of the shaft has a gear well attached, so I decided to simply glue this gear onto the brace I built rather than trying to get the gear off by force (which won't be happening anytime soon).

The brace is a very high tech contraption I built from my old erector set. It simply holds the camera and keeps it from twisting around too much. I still have a problem with the cable leading from the camera, as it tends to pull on the camera if the motor turns it too far. I therefore set a maximum rotation angle to 90 degrees. This is adaquate to view most of the room and everyone in it.