Tactile Light Switch Using Chipless RFID

This letter introduces a tactile light switch (TLS) that is passive, battery free, and relocatable. The switch utilizes physical touch to control electrical devices, such as light bulbs and TVs. TLS is a chipless radio frequency identification (RFID) tag with an integrated tactile-sensitive element. It is achieved by incorporating three radio frequency spiral resonators, namely, a sensing resonator and two identification (ID) resonators. Each resonator is designed with a unique resonant frequency that is used to passively communicate the status of the TLS tag. The sensing resonator is touch sensitive, and the presence of its corresponding resonant frequency (f_RS) is controlled by touch. The ID resonators have fixed resonant frequencies (f_IDR1,2) that are used for tag identification. The TLS tag is designed and fabricated using a 1.6-mm-thick FR4 substrate. The measurement results show resonant frequencies at 1.02, 1.08, and 1.19 GHz, corresponding to f_RS, f_IDR1, and f_IDR2, respectively. A direct touch on the surface of the sensing resonator successfully cancels the resonant frequency at f_RS, whereas the resonances at f_IDR1,2 are unaffected by touch and are always present for identification.