Abstract: A sensor device includes a first antenna configured to receive an interrogation radio frequency (RF) signal; a first sensor configured to detect a first state of a first sensed signal, to output a first sensor signal responsive to the first state meeting a first threshold condition; a first circuit coupled to the first antenna, the first circuit configured to receive the interrogation RF signal from the first antenna, modulate a second RF signal, and transmit the modulated second RF signal as a RF response signal; and a first tag controller configured to receive the first sensor signal and to selectively connect or disconnect the first antenna to or from ground responsive to the first sensor signal, wherein connecting the first antenna to ground prevents the first antenna from transmitting the RF response signal.