In this work we present experimental results that show a resonance effect in the isotropic phase of a lyotropic liquid crystal. The lyotropic mixture is made up of Potassium Laurate (KL), Decanol (DeOH) and water with three different relative concentrations: 2.62, 2.79 and 2.90 (C = [KL]/[DeOH], [KL] and [DeOH] in % molar). These mixtures have an isotropic (ISO) phase between two lamellar phases as a function of the temperature. From the transmittance of the sample (I) as a function of the frequency (f) itwas possible to evaluate a characteristic time (tau) in order of magnitude as a function of the temperature (T). The existence of a maximum in tau vs. T around 30ºC indicates the possibility of employing lyotropic liquid crystals in mechanical vibration sensors. We are proposing a mechanical vibration sensor able to measure low mechanical frequencies (f <= 200 Hz).