Embodiments of the present invention relate to a pulse oximetry sensor. The pulse oximetry sensor may comprise an emitter configured to transmit a signal into tissue, a detector configured to detect the signal, and a quality assurance component coupled to a first sensor component and second sensor component....http://www.google.de/patents/US7684842?utm_source=gb-gplus-sharePatent US7684842 - System and method for preventing sensor misuse
