The use of RF identification (RFID) technology for the automatic transmission of physical parameters in wireless sensor networks paves the way to a large class of attractive applications ranging from healthcare to automotive, diagnostic systems, robotics, and many others. Nevertheless, although some RFID tags capable to transmit sensor-like information are already on the market, only a limited number of sensors, such as those for temperature or pressure measurement, can be easily miniaturized and embedded in the RFID chip. The integration of more complex sensors, in fact, appears to be complicated and extremely expensive. In this paper, a cost-effective general-purpose multi-ID tag is proposed. It can be connected to generic sensors, regardless of the actual measured value, and it is capable to transmit, when interrogated by a standard RFID reader, a proper combination of ID codes that univocally codifies the sensor measured value. The functionalities of this device have been extensively validated under stressing conditions and the capability to transmit whatever kind of sensor data has been demonstrated.