Without Eyes and ears humans can't able to see and hear. Like that without sensors robot can't able to see, hear, speak, sense. The sensors are the sensory organs of robot. There are various types of sensors at now a days. These sensors helps the robot to act like humans. Some of them are : 1. Ultrasonic sensor - used to detect the obstacles and distance. 2. IR sensor - used to detect light rays and fire. 3. Thermo couple sensor / Temperature sensor - used to detect temperature.