Friday, April 28, 2017

Detected EEG wave that can tell whether eyes are open or closed

This humble equipment which hides in the paper box can detect and record EEG wave now. By filtering and Fourier transformed to the frequency domain, we can tell whether the testee's eyes are open or closed. The middle part of the graph, which has lower signal, is the period of time that eyes were closed.




When eyes closed, the amplitude of the signal decreased significantly. It has a great difference with the signal that generated when eyes are open.

And when eyes are open, the beta wave which mainly distributes around 20Hz appears, together with some other higher components.

In the beginning, I was guessing the widely distributed signals are noise, they look like white noise or 1/f noise. After deep investigation, I confirmed that it's EEG signal, and mainly is the beta wave.

And happily, I got to know a guy that is currently pursuing his master's degree in a university in Canada, he is studying the method of detect epilepsy evidence in EEG wave. He is using wavelet to extract some specific wave from the signal. He would be a great help to my project.

Tuesday, April 25, 2017

My first ECG signal recording

For the first time, I made it, I recorded the ECG signal, by this messy, tiny circuit.


Figure: The ECG signal



The circuit was designed by my partner


Here is the system structure:

human body -> electrodes -> leads -> ADS1298 -> serial port -> PC -> C# app -> matlab