Transponder and a sensing system using the transponder

A reader/writer comprising:

• a second coil antenna for carrying communication between a plurality of transponders each having a unique identifier combining a transponder chip identifier and a sensor identifier;
• a communication circuit to which said second coil antenna is connected;
• an oscillator;
• a modulator for modulating an oscillation frequency generated by said oscillator and supplying the resultant modulated signals to said communication circuit;
• a demodulator for demodulating signals resulting from the reception by said communication circuit of signals sent from said transponder via said second coil antenna;
• and
• a control block for controlling said oscillator, said modulator, said communication circuit and said demodulator, provided with:
• a command for invalidating a transponder chip identifier out of said unique identifiers in order to enable transponders each with a built-in prescribed sensor out of said plurality of transponders to start measurement.

A sensing system comprising a plurality each of transponders each having one type of built-in sensor matching one type of measurement item for each type of measurement item, wherein:

• a plurality of sets of data are acquired for each of a plurality of measurement items by performing communication between said plurality of transponders and the reader/writer;
• each of said transponders has a sensor identifier matching the type of sensor, a transponder chip identifier intrinsic to each transponder, and an intrinsic unique identifier combining said transponder chip identifier and said sensor identifier;
• and
• said reader/writer, in communicating with said transponders, transmits to transponders a command to invalidate the transponder chip identifier out of said unique identifiers, validates the type of sensor matching the measurement item, and causes said plurality of transponders having the same matching type of sensors to start measurement.