Control of randomly scattered surface plasmon polaritons for multiple-input and multiple-output plasmonic switching devices. Nat. Commun. 8, 14636 doi: 10.1038/ncomms14636 (2017).

Bit patterns show the states of input and output devices. Circuits with digital inputs and outputs are designed and interpreted, and amplification is needed to drive certain output devices from a PIC.

These devices might use sound or types of movement like head or eye movement, to control a pointer or on-screen keyboard. Some can even use our breath as an input method.