In my diploma thesis I aim to create a working, one - channel ECG device. The task involves the visualization of ECG - signals collected from the human body.
The thesis - work consists of two semesters, in which my first thing to accomplish was to study the corresponding written and online material in the field, and get to know other ECG projects. After I had collected enough experience, the next step was to begin designing the overall system - structure. This task includes the design of both hardware and software elements of the ECG. According to the design scheme, I had to implement the analog front - end structure under the microcontroller' s environment. After the A/D conversion of the real - time signal, I had to send the converted digital datastream to the PC, then process and visualize it with a proper host application. (My choice for the microcontroller was PSoC 5, from Cypress.)
The code designing of the host application is also a part of the diploma thesis (in C#).
There was more than one possibility to choose from when I had started thinking of the analog structure design: one way was to use an AFE (analog front - end) that can be bought from the market, and incorporates all the functionality of an ECG front - end (for example the ADAS 1000 from Analog Devices). Another approach is to create the analog front - end externally, then A/D convert it, and feed the signal into a microcontroller for further manipulation. The third - and preferred one - approach is to implement the AFE in a microcontroller, that incorporates integrated programmable analog functionalities and peripherals (like op - amps, MUX, Delta - Sigma A/D, etc.), thus making the design easier, and require less external parts. My choice for the microcontroller was PSoC 5, from Cypress.
For better precision, the instrumentation amplifier (INA) is attached externally to the AFE structure, as a separate IC.