Word counting pen

This is one of those ideas that might be useless or it doesn’t really try to solve a problem or anything. With the fever of wearable devices, I thought that it would be nice to have a pen that helps (middle, high, college etc.) students write their essays (an still use pen). The pen would have a display that will count the number of words a user has written, and vibrate to announce him that he misspelled a word.

The biggest problem is that nobody uses pens to write their essays, everything is done on the computer nowadays.

EDIT: looks like someone invented this http://www.lernstift.com/index_en.html