The paper dedicated to vibration measurement system development on the Raspberry Pi basis. Main features of the solution are low-cost, easy access to components and functionality and flexibility provided by Raspberry Pi usage. Circuit solution and configuring procedures are presented and described. In particular, block diagram of the vibration measurement system with piezo-electric sensors. Two variants of the vibration measurement system, on the Raspberry Pi B+ and Raspberry Pi 3B correspondingly, were implemented and tested as well. In addition, two variants of impedance-matching device were implemented. Conducted and described experiments confirm performance both separate components and the whole solution. Presented results are applicable for correlation leak detectors new algorithmic solutions and in educational process.

In medical devices required in electrocardiography, electroencephalography, electromyography, electrooculography, etc. the most important element is the medical electrode intended for measuring biopotentials. The optimal selection of electrodes is possible only after testing them to confirm the claimed manufacturers' parameters or determine the real metrological characteristics. Technical characteristics of measuring instruments produced by domestic producers or supplied by foreign companies are regulated by the State Standard GOST 25995-83. Thus, in accordance with this standard, calibration equipment has to have inherent noise level (basic parameter) up to 15 μV in a frequency band up to 10 kHz. However, this requirement does not satisfy modern trends of medical instrument engineering in connection with the appearance of new medical nanoelectrodes on the market, including domestic production. A hardware and software complex for researching medical electrodes (HSCRME) was developed at Tomsk Polytechnic University. It allows measuring the parameters of electrode cells: an electrode potential difference; a drift of the electrode potential difference; a noise voltage; an electromechanical noise; an impedance of electrodes; a polarization voltage. The HSCRME includes a measurement analog channel (AMC) and a digital subsystem being a personal computer. The AMC is configured automatically when the user selects the appropriate mode depending on the measured parameter of the electrode. Cross-platform application framework Qt is the software foundation of the HSCRME. Potential possibilities of the HSCRME are determined by the noise of AMC. The noise applied to the input of AMC did not exceed 1 μV (rms) in the frequency range 0...10 kHz. Verification of the complex was carried out by the inductive voltage divider, which is part of State Standard GAT193-2011. This State Standard is stored in VNIIFTRI (Moscow).

There is an urgent need to improve system design of calibration equipment which allows us to determine parameters and characteristics of medical electrodes. Technical characteristics of a hardware and software system for researching medical electrodes are depending on amplitude–frequency responses of a measurement analog channel. This channel consists of an instrumentation amplifier, a cascaded chain of operational amplifiers including programmable-gain amplifiers and a low-pass filter, therefore calculating amplitude–frequency responses of a measurement channel is a multiparameter problem. This problem can be solved efficiently by simulation with help of Matlab. Simulink-model of a hardware and software system for researching medical electrodes is suggested. The model provides the correct design of a measurement channel. It is subject to design criteria such as accuracy of frequency band and a reduction in gain.

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