• Robots use cameras to see and microphones to hear.robot image by Paul Moore from Fotolia.com
  
  Engineers have improved the sophistication and versatility of robots by giving them sensors. Coupled with computers and software, sensors can enable a robot to navigate its environment, manipulate objects, respond to commands and work autonomously. Robotic sensors roughly correspond to the human senses of sight, sound and touch. Rangefinders and cameras serve as a robot's eyes; microphones pick up sound; and accelerometers and force sensors let it feel its surroundings.
  
  

Rangefinder

• Many robots use rangefinders to find the distance to walls or obstacles. The rangefinder emits a sound or light pulse, detects its reflection from an object and determines the distance to the object. Most rangefinders can establish distances to a maximum of about 20 feet. In addition to distance, the robot can use rangefinder data to determine if an object is moving.
  
  

Camera

• Sophisticated robots use cameras coupled with high-speed computers and software to determine the locations and shapes of objects. Engineers and scientists call this "machine vision." Industrial pick-and-place robots, in particular, have become adept at identifying workpieces. Sufficiently advanced machine vision systems can identify written symbols, bar codes, hardware and people's faces.
  
  

Microphone

• Sometimes a robot needs to "hear" what's going on in its environment. Microphones can let the robot process and record sounds. It can use a pair of directional mikes to identify a sound's location or an omnidirectional mike to pick up sounds regardless of their origin.
  
  

Accelerometer

• Advances in solid-state accelerometers have made them small and inexpensive enough to see use in everyday devices such as smart phones. In addition to sensing changes in motion, an accelerometer can detect a robot's orientation with respect to the ground since gravity provides a natural downward acceleration. A robot that senses its own orientation can climb over obstacles better and right itself if tipped over.
  
  

Force

• Force sensors help robots manipulate objects with sophistication. For example, gripping an egg tightly enough to lift it but not so tightly that it cracks takes force sensing. Turning screws and seating parts requires a robot to sense force limits. Force sensors can also improve safety by shutting down a blocked or jammed robot.