The design and operation of new viscometers are often presented with a focus on the miniaturization of the device and online monitoring of small amounts of liquid samples. The vibrational viscometers commonly used for viscosity measurements exploit the peak value of the frequency-response curve obtained from excitations of the oscillator submerged in the liquid. However, for high-viscosity liquids, the peak of the frequency-response curve is ambiguous or nonexistent, and hence hard to measure. To overcome this drawback and with a view to miniaturizing the device, we use the self-excited oscillations produced by a velocity feedback control. Our design uses a viscometer employing a cantilever driven by a piezo-actuator with analytics that do not rely on the frequency-response curve. A prototype piezo-driven macrocantilever with an oscillating plate attached at its tip was experimentally performed according to specifications. The proposed mechanism can be integrated into microelectromechanical systems (MEMS).