The RoboReptile only has two types of internal sensors, encoders and tilt sensors. All reside inside the torso. The neck encoder is used to determine the left/right orientation of the neck with respect to the torso. The mouth encoder determines if the mouth is open, closed or somewhere in between. The tilt sensor is used to determine if the RoboRaptor is sitting or standing.
The RoboReptile has several different forms of external sensors. The newest is the "CDS" sensor, I have yet to determine exactly what this is, but it detects if the RoboReptile is hooded or not (or if the amibient light level is low). The IR LED's are coupled with the IR Receivers to detect obects to the left and right of the RoboReptile's head. The IR receivers also receive the signals from the remote. The two microphone's allow the RoboReptile to detect loud noises on its left or right. Finally there is a single touch sensor on the RoboReptile's back, this is use only for interaction with humans.