Patent ID: 6885201

Claim:
A portable electronic device including powering means for powering electronic circuits including a data processing unit, said electronic circuits being housed in an assembly formed by a case closed by a glass, the device further including a pressure sensor and means for detecting the presence of water capable of producing electric signals to be sent to said data processing unit, said detection means including at least one capacitive sensor including a capacitor, one plate of which is formed by an electrode arranged on an inner region of the case-glass assembly and whose capacitance is capable of varying following a modification in nature of the external medium located directly in contact with an external region of the case-glass assembly opposite the electrode, said region coming into contact with water, wherein said pressure sensor operates in at least two powering modes, a first mode is the surface mode and a second is the dive mode and wherein said detection means are periodically activated to carry out measurements of a quantity representative of the value of the capacitance of said capacitor, said electronic circuits further including means for comparing at least two successive measurements of said quantity and producing an electric signal for activating said dive powering mode in response to a variation in said capacitance between two successive measurements of said quantity higher than a predefined value.