his paper presents a mobile diagnostic system for gears and other rotating mechanisms. For mobility, we use a non-contact displacement measurement method based on the Doppler Effect for electromagnetic waves. Microwave radar sensor with quadrature conversion directly measures the current small movements of the reflective surface of an object. Subsequent signal processing system performs a sequential search for predefined frequency signatures of defects. Subsequent signal processing system performs a sequential search for predefined frequency signatures of defects. We take the features from databases of components of the object under study or calculate them using the corresponding formulas for pinions, gears, and bearings. Calculation algorithm uses timesynchronous averaging, envelope calculation, spectral analysis, and frequency descriptors to reduce the signal-to-noise ratio.