RFID Tracers

 

The RFID (Radio Frequency IDentification) technology is composed by two devices: an RFID radio signal antenna (or RFID reader) and a transponder (or tag). The tag is provided by an alphanumeric code which is the element allowing the univocal identification of the item to which is coupled. The RFID reader generates a sphere shaped electro-magnetic field with a 40 cm radius, which represents the maximum detection range both underwater and in subaerial environments. The electro-magnetic field is able to interrogate the tag inserted inside the pebble. The technique is really useful to trace coarse sediments and to monitor their displacements in the short and long term in a large variety of environments (fluvial, coastal, landslides, etc.). When a tracer is found, the laptop (or smartphone), which is connected to the RFID reader, emits a sound to make the operator aware about the tracer recovery. The alphanumeric code of the tracer appears on the screen with several information about the pebble characteristics. The technique works also underwater.