A sensing system includes a ring oscillator that emits electromagnetic radiation at a characteristic frequency. The ring oscillator comprises an odd number plurality of inverters that are electrically connected in series. The sensing system also comprises a temperature stabilized voltage source that is used to supply voltage to the inverters of the ring oscillator. A sensing load for sensing a change in a preselected environmental condition is operably connected to the ring oscillator. When the load senses the preselected environmental condition, the sensing load alters the characteristic frequency of the ring oscillator and hence the electromagnetic radiation as emitted by the ring oscillator. A pick-up antenna receives the electromagnetic radiation as emitted by the ring oscillator and detection electronics, operably coupled to the pick-up antenna, measure the frequency of the electromagnetic radiation as received by the pick-up antenna.