Need a hug? Build a hug robot and get your fill! via instructables
Hugbot is a soft robot which gives small hugs. Its arms are made of custom 3D printed vertebrae and actuated by fishing wire which is threaded through the vertebrae to stepper motors controlled by an Arduino inside its body. Hugbot was born of an interest in making something soft and squishy which could move based on its outside environment.
They key to Hugbot is its arms, made of 3D printed joints with two strings running through them. Pulling one string or the other causes the arm to bend. Hugbot is simply two of these arms, each hooked up to a pulley on a stepper motor controlled by an Arduino Uno. A flex sensor in its head provides input for when the arms should open or close.