Just for kicks and giggles, I dug out my Sony video camera and used it to take some video of Roomba. It's one of those Sony cameras that does the 'Nightshot' thing letting you see in low-light conditions by illuminating the area with an IR emitting diode. It also lets you see the IR lights that Roomba and its various components use. The pictures are posted over in the gallery.
This is Roomba's base station. The IR signal it broadcasts out the top is what Roomba uses to find it's way home. It comes on automatically when Roomba is turned on or is removed from the base station.
This is the light pattern broadcast by Roomba's Virtual Wall. It's actually a circular beam. It just looks like that because I have it pointed obliquely at the wall. The VW has 3 range settings which simply controls the intensity of the IR beam that is broadcast.
I just thought it would be a fun geeky thing to do.