We interact with the world using our five senses: sound, sight, smell, touch and taste. Conceptually robots are capable of these and many more inhuman senses. A sensor is defined as a mechanism that receives input externally and relays this input to the main control system. Detailed below is a list of the most common sensors and there application to the real-world.
Light Sensors
Light sensors have numerous ways of being deployed but from a very basic view point, they detect light using photosensitive components and relay this information to the robots control unit. One particular implementation transmits infrared waves out to its environment and uses infrared receivers to detect the reflections. This allows it to perceive its environment and safely navigate between two points without colliding with any objects. When mobile automated machines are required to run in a straight line, a white luminous track is placed on the ground and the machines light sensors are used to align the robot. Light sensor circuitry can also be configured to attract the robot towards light allowing the robot to navigate around a set course.
Sound Sensors
Sonar is the primary technology used with sound sensors. The speed of sound is measured using the sensor to detect the proximity of external objects and this input is used to navigate the machine. High-pitched signals are transmitted from special sound emission units and relayed off external masses back to the robotic receivers. The time it takes for this process to cycle can be easily converted using simple calculations to reveal the distance of the object. Proximity and distance detection is very important in mobile robotics, as it allows machines to carry out complex manoeuvres in hazardous environments. Sonar components are now relatively cheap due to their widespread use with camera technology, with most cameras now equipped as standard with sonar sensors.
Pressure Sensors
This type of sensor is a switch that submits a signal depending on whether it has been switched on or off, to some sort of automated control system. Bumper sensors are the most common type, helping robots navigate through their environment using signals from the control system. Pressure sensors come in many different forms, from whiskers to simple pressure plates and engineers are constantly evolving the ways these are used.