In this line of research (since 2013), we investigate how users might interact with devices smaller than mobile or wearable devices. We argue that to achieve the intended minimal form-factor such devices will leverage the user's body as an input and output device. Users will not interact with the device but instead will interact through one of their limbs, which they share with the computer as the interface.
We present six research projects and one art piece, in which these wearable devices actuate the user's limbs by means of electrical muscle stimulation and are perceived through the body (proprioception). We explored two main benefits of these EMS-based devices: (1) supporting realism by simulating forces in Virtual Reality and (2) rendering information directly to the proprioceptive sense, opening up new modalities for I/O devices.