Robots can express emotions for better Human Robot Interaction (HRI). In this field of HRI, the Nao robot is a platform widely used. This robot mainly expresses emotions by gestures and colored led eyes, but due to its white flat and inanimate face it cannot express facial expressions. In this work we propose a pluggable eyebrows device with two separated degrees of freedom. A short survey is conducted to qualitatively evaluate the usefulness of this device.