Existing wearable devices like an eyeglass-type head-mounted display(HMD) are very bulky and cannot be worn everyday. On the other hand, the earphone is popular wearable device, bacause it is small. However, the earphone cannot be used as an interaction device because of the lack of input and visual feedback components. In this paper, we propose Brainy-Hand - an enhanced earphone device for use in interaction systems. Brainy-Hand consists of a color camera and a laser projector. The camera recognizes the user's hand gestures for the input. For the visual feedback, the images projected on the user's hand or other nearby objects or surfaces using the projector. Since laser microprojector is becoming small, we expect this device configuration would eventwally a become as small as today earphones. We introduce several interaction methods based on hand gesture recognitions and object detections.