The LUCS Haptic Hand I together with a set of haptic models is the first in a series of projects aimed at studying haptic perception for building several robotic hands together with cognitive computational models of the corresponding human neurophysiology. The haptic systems have been trained and tested with a set of objects consisting of balls and cubes, and the activation in the modules corresponding to secondary somatosensory cortex is studied. The results suggest that the haptic system is capable of categorizing objects according to size, if the shapes of the objects are restricted to spheres and cubes.