In order to help visually impaired people judge the heat when washing their hands, this faucet knob senses the ups and downs of heat through tactile changes. Unlike traditional faucet knobs, the top of the knob is made of soft silicone. When the knob is turned to increase the water temperature, the water temperature is pushed to the silicon top through the sensor to cause it to bulge. The higher the temperature, the greater the bulge. Visually impaired people will be able to feel changes corresponding to the water temperature level, thus avoiding scalding. The water temperature level indicator at the bottom of the knob also makes it easy for ordinary users while reducing water waste.