This is not new at all. In the early 90s I had a Casio plastic watch that used a very similar method. http://digital-watch.com/DWL/1work/casio_bp-100/ http://di

This is not new at all. In the early 90s I had a Casio plastic watch that used a very similar method. http://digital-watch.com/DWL/1work/casio_bp-100/ http://digital-watch.com/DWL/1work/casio_bp-100/ A capacitive sensor to detect finger pressure and an optical one for the blood flow. Even cheaper than using a scale to detect pressure... The accuracy of course leaves a lot to be desired.