Zero power sensors

An environmental physical sensor comprising:

• a power input terminal;
• a sensor output terminal;
• a first resonant switch including a first mechanical element responsive to a first component of an environmental stimulus, and a first electrical switch coupled to the power input terminal and coupled to the first mechanical element and operable between an open position and a closed position, the first mechanical element configured to intermittently actuate the first electrical switch into the closed position responsive to the first component;
• and
• a second resonant switch including a second mechanical element responsive to a second component of the environmental stimulus, and a second electrical switch coupled to the first electrical switch and coupled to the sensor output terminal and coupled to the second mechanical element and operable between an open position and a closed position, the second mechanical element configured to intermittently actuate the second electrical switch into the closed position responsive to the second component.