Abstract: The instrumented device comprises a body to be attached to a mixing valve producing a mixed fluid by blending hot and cold fluids. The body defines a main channel and a bypass channel, provided for the outflow of the mixed fluid through the body. The device comprises a turbine arranged in the main channel, being bypassed by the bypass channel, such that, as soon as the flow rate of the mixed fluid flowing through the body is non-zero, all or a portion of the mixed fluid flowing through the body passes through the main channel passing through the turbine and, at the same time, a portion of the mixed fluid flowing through the body is likely to bypass the turbine by flowing in the bypass channel between the upstream and the downstream of the turbine.