[Alan Anderson]

The "dark purple" is what you get if you think of the values as RGB and fail to interpret them in the YCrCb color space instead. The camera picks up on the green glowing color wonderfully if it's switched to YCrCb, which is what the provided code does.

By the way, the maximum reported color value from the camera is 240. In RGB mode, a sufficiently bright light of any color -- including the green target light -- saturates the camera at 240,240,240.