The work is devoted to the problem of developing a portable and easy-to-implement spectral express analyzer prototype for MEMS optical systems. The novelty of this study is new approaches to photodiode signal converting and the technique of spectral express analysis. The signal converter is implemented on the principle of trans-impedance amplification, which ensures high linearity of the conversion of the input photocurrent into the output voltage and a wide frequency band. Model studies with the approximation of spectral characteristics by mathematical Gaussian functions were used for the express analysis. The hardware and software of the express analyzer based on Color Light-to-Digital Converter TCS3400 are presented. The results of the work are used to study the parameters of MEMS mirrors of optical systems and develop optical sensors based on them.