Fecha de publicación: 06/06/2013 Fuente: Wipo "precision agriculture" There is disclosed a calcium sensor comprising a transducer layer; sand sensor further comprises; at least one substrate for conductor layer seeding; at least one conductor tofunction as an electrical contact; a self-doped polythiophene transducer that functions as transducer layer for electron transfer a carbon layer to function as a seeding substrate for the self-doped polythiophenes transducer layer; a calcium sensing membrane as a polymeric membrane and to function as calcium detector; and a retaining dam to hold calcium sensing membrane to not flood and carried out from surface area.