I want to record some lectures I am giving next semester. I have a video camera, and can change its direction using a servo of some sort. However I have no idea how to detect where I am. Me carrying some broadcasting device would be fine. Mostly the sensitivity should be able to determine if I am in the left or right side of the room, but I do not need much more than that.
You could wear some simple IR LEDs, you could then also place a number of IR receivers, just simple IR photo-diodes would work, with a narrow viewing angle.
If you place these around the base of the camera and then have a microcontroller read which one has the greatest signal you can point the camera towards the IR source.
Sounds complicated, but it is very simple, and does not require a computer. The hardware is easy to do, although you will probably find in noisy environments (bright light) you will want to modulate your IR to get away from broadband noise you receive.
What you are looking for may be related to "blob tracking". It's a commonly used technique in robotics and vision processing.
Depending on your programming chops, you can use OpenCV (open source computer vision libraries) available in both C++ and Python. Other languages may have libraries that support blob tracking. I believe that LabVIEW and Matlab also have libraries to support this.
Generally, the setup will be a computer processing the video and finding a blob (you) of a particular color. You can then use the information of the position of the blob in the camera frame to determine where to point the camera. If you are, for example, driving the servo on the camera with an Arduino (or any other microcontroller), you can send commands via the serial port to update the desired position of the camera. When the blob leaves some desired "box" in the center of the frame.
If you want, you can do some more clever tracking by implementing some combination of Proportional, Integral, and Derivative control (PID, if you are searching around the internet), to try and keep yourself centered in the frame, but this may be more than you need for your application.
Edit: A bit of searching yielded this result: Creative Applications. This is more or less the solution that I explained.
I am the person who asked this question, and I really like both the OpenCV answer and the IR led answer and will be playing with them both. At this point both have some issues for me though: my IR led order is getting delayed, and my webcam is unwilling.
That being the case my eye fell on an LV-Maxsonar EZ that I bought to play with a little while ago. I never really got to it, but now it seems like it might give rise to a decent solution here. I am the only person moving in front of the room, so no interference, and no computer needed either.
This device gives distance measurements in a specific direction. If this distance changes someone moved in front of it, and the camera should move in the direction that that sensor is pointing.
Check out the PrimeSense devkit (the makers of the Kinect)
The manufacturer released the Kinect's (and DevKit) Windows and Unix drivers here: http://www.openni.org/
Tracking IR splash (and filtering it from the camera, the room's insolation agreeing) give you and the students a good chance at ADR work that helps put you and your chosen context in zone zero. That said I would have probably have drawn from a bundled webcam application well-reviewed on Cnet.com (or another critical venue, Amazon, Acer Support or otherwise) or Camtasia and used that as directed.