Patent ID: 8860399

Claim:
A monitoring device for at least one physical characteristic of a building material, the monitoring device buried inside a block of the building material and comprising: a sensor buried inside the block of the building material and configured to sense the at least one physical characteristic and comprising a secondary inductor and a circuit coupled thereto, said circuit configured to generate an internal supply voltage for said sensor when immersed in a variable electromagnetic field and to transmit a signal representative of the physical characteristic; and a wireless power supplier buried inside the block of the building material and configured to generate the variable electromagnetic field for said sensor and comprising a dielectric layer and a resonant L-C circuit therein, said resonant L-C circuit comprising a primary inductor configured to be magnetically coupled to said secondary inductor of said sensor, said wireless power supplier further comprising two current terminals extending from said dielectric layer to external the block of the building material so as to be coupleable to an external reading circuit for the signal; said sensor being adjacent said dielectric layer so as to magnetically couple said primary inductor and said secondary inductor.