Looking at a collection of expression and emotion

Another idea for a book is to make a collection of portraits, using a range of people and looking at different facial emotions of how they are feeling. I could either use the studio for some shots using people i know, or by going out in to the public and giving people a board to write on how they are feeling and holding it up in front of them showing their expressions. This would be making a collection of expression and emotion within the community.