What most of us in the forum are looking for is patterns. As a way to “reduce noise” on your search for patterns, you may check without stress how does the blinking and talking affect. And then eliminate those patterns and just look for the differences between stress and calm. So do a “hello” call to someone nice, record the call and watch correlations with talking vs brain waves, and then compare with the stressful call. Trying to discard all the moments where you are actually talking which affects the waves.
There is a gyroscope too, so you may try to do the things without moving the gyroscope.