We use small, lightweight and inexpensive vibrating actuators
(e.g. eccentric-mass dc-motors and/or voice-coil motors), which
are common in current phones, toys, tablets, controllers, etc. They
consume low power and usually require a small driver circuitry.
Along with embedded electronics, these components are housed in
the device contacting the skin. For example, the actuators and
electronics are embedded in a tablet sleeve (Fig. 2a) and electronics
are mounted on separate compartments in the glove (Fig. 2b).