1. Robot Sensors: Robots come in many designs, and perform many functions. One way of helping control these robots is through sensors. ©Emil Decker, 2009

2. Sensors are components that imitate the human senses. Sight, hearing, and touch are the most prominent, but even olfactory senses are possible to mimic. Robot Sensors: ©Emil Decker, 2009

3. Sound sensors can detect sounds, sending a signal to the microprocessor to alter its program accordingly. Robot Sensors: ©Emil Decker, 2009

4. Ultrasonic sensors operate at frequencies humans cannot hear. They bounce sound off objects to determine distance just like bats do. Robot Sensors: ©Emil Decker, 2009

5. Optical sensors work with various light frequencies to deliver input to the microprocessor. The most popular are infra-red reflective sensors. Robot Sensors: ©Emil Decker, 2009

6. Touch sensors detect applied forces to close switches, activate circuits, etc. The force necessary to activate these sensors may be the slightest touch to a firm pressure. Robot Sensors: ©Emil Decker, 2009

7. Acceleration sensors work on Newton’s second law. Accelerometers can measure distance or determine if your robot has hit something. Robot Sensors: ©Emil Decker, 2009

8. Encoders are digital transducers. Connected to a rotating shaft, they can determine direction and distance based on rotation. Robot Sensors: ©Emil Decker, 2009

9. Sensors can include magnetic sensing, thermal conditions, humidity, inertia, differential gas or chemical detection, as with bomb sniffing robots. Robot Sensors: As it increases its use of robots in war zones, the military will begin using an explosive- sniffing version that will allow soldiers to better detect roadside bombs, which account for more than 70 percent of U.S. casualties in Iraq. (AP Photo/Al Behrman) ©Emil Decker, 2009