The smartness of PDLCs is a result of their ability to change their transparency (technically called the "transmittance" when an electrical stimulus is applied to them. This is normally by way of an alternating voltage, which exerts an alternating electric field across the PDLC material. Nevertheless, the PDLC is only as smart as the control system which stimulates the change, which can be driven by a push-button switch, a light sensor, or a building automation system. What are the major reasons for using PDLC smart glass? http://www.smartglassproject.com/laminated-glass/pdlc-smart-glass/