In this paper a new sensor for the non-invasive monitoring of the oxygen saturation in blood has been designed, realized and tested to obtain an ultra-small device having very high noise immunity. This goal has been reached by using a particular integrated circuit, the PsoC (Programmable System on Chip), which integrates two programmable arrays, one analogue and one digital, to obtain a device with very large capabilities. We have configured the PsoC and developed the electronic interfaces. The proposed design allows the acquisition of the continuous component of the signal and the data elaboration has been done in place using a local CPU, without requiring to pass data to an external computer.
