After much experimentation and prototyping and testing, I have decided to narrow down on the types of sensors and the location of the electrical stimulation. For the sensors I have decided:

 1. Pre-frontal cortex activity 

 2. Eye movement 

 3. Heart Rate and Sweat Response 

And for the stimulation location - because of the experience of having my cerebellum (the back of my brain responsible for balance) and because of the difficulty to have contact with the skin on most parts of the body, I have decided to explore the stimulation of this part of the brain.