The diploma project is dedicated to the development of an automated device for measuring the onset time of blood coagulation using the impedance method based on the AD5933 microchip. The goal of the work is to create an accessible, portable, and accurate tool for monitoring the coagulation properties of blood in both clinical and home settings.
Impedance spectroscopy is a promising technology that allows for the detection of changes in the electrical resistance of biological tissues, particularly blood, during the coagulation process. In this work, the AD5933 is used to generate a sinusoidal signal and analyze the complex impedance response of the sample through digital Fourier transformation. An STM32 microcontroller is used to read data via the I²C interface, compute the impedance magnitude and phase, normalize the impedance, and perform real-time analysis.
The project includes an analysis of classical methods for monitoring blood coagulation, such as the Lee–White and Burker methods. It has been found that traditional techniques require qualified personnel, are labor-intensive, and are not well-suited for automation. In this regard, the impedance-based approach simplifies the measurement procedure and reduces the likelihood of error through digital signal processing.
The project involves the development of structural, functional, and circuit diagrams of the device, justification for component selection, PCB layout of the main circuit blocks, creation of a 3D model, development of a blood sampling design, and the implementation of the device’s operation algorithm. The microcontroller determines the amplitude and phase values.
Theoretical studies have confirmed the effectiveness of the method: impedance changes proportionally to the formation of the fibrin clot, which allows for high-accuracy determination of the coagulation onset.
The developed device can be used in laboratories, point-of-care diagnostic stations, and also as a training platform for studying the bioelectrical properties of fluids.
Research advisor: V. Bazhenov
