The four-legged “guard dragon” robot sense smoke and alert its owners to a smoldering fire – via a howl or a mobile phone text message. The robot is one meter long, 80 centimeters high, 70 centimeters wide and weighs 40 kilograms. It can move at a top speed of 15 meters per minute – more than fast enough for a home robot designed to travel in confined, cluttered spaces, its designers say.