The aim of the Greetometer Handshake Trainer (from Meg Grant) is to have computers to teach humans how to give better handshakes.The Greetometer measures three aspects of the handshake: angle, grip and sweaty palms. Feedback for the angle (balance) is given via two small vibration motors on the back of the hand. The motors guide you to roll your hand clockwise or anti-clockwise. Feedback for grip is given audibly with a small piezo element. Grip too hard or too softly and the alarm sounds. Sweaty palms are measured on a colour range. Link.