Self-powered sensors for long-term monitoring

A method for detecting events using a sensor including a transducer and a memory device including a floating-gate transistor with a sensing interface coupled to the transducer, the sensing interface having an energy barrier configured to leak electrons at a predetermined electron leakage rate through Fowler-Nordheim (F-N) tunneling, the method comprising:

• detecting, by the transducer, an event;
• generating a sensor signal in response to the event;
• altering a geometry of the energy barrier in response to the sensor signal, wherein altering the geometry changes the electron leakage rate;
• and
• storing, at the floating-gate, data associated with the electron leakage rate, wherein the event and a timestamp of the event are identifiable from the stored data.

A method for monitoring ambient temperature of an object, the method comprising:

• disposing a sensor adjacent the object, the sensor comprising a memory device comprising a floating-gate with a sensing interface having an energy barrier configured to leak electrons at a predetermined electron leakage rate through Fowler-Nordheim (F-N) tunneling, wherein the electron leakage rate varies at least partially as a function of an ambient temperature of the sensor;
• altering a geometry of the energy barrier in response to a change in ambient temperature and thereby change the electron leakage rate;
• and
• storing, at the floating-gate, data associated with the electron leakage rate.