Measuring Card For Electrical Impedance Tomography

Abstract

This project aims to design and to implement measuring card for electrical impedance tomography (EIT). The main function of the card is to switch the voltage measuring electrodes and to select the feeding current polarity on any tomography electrode. The commonly used commercial cards utilize the relays. The main problems of this approach are speed of the switching, selfconsumption, size and signal noise. Our solution consists in utilizing the MOSFET technology with optocoupler to isolate the feeding and measuring electrodes galvanically. The MOSFET optocouplers are driven by the shift registers controlled by the Raspberry Pi Zero embedded system.