Sensor Intro

Introduction to Sensors ¶ 

Original seed article by Matt Mets

Sensors are the devices that allow us to detect things happening, not only in the world around us, but inside of us as well. Everything that wants to know what's going on around it needs them, including animals, plants, and robots.

As humans, most of us have some combination of eyes (sight), ears (sound), nose (smell), tongue (taste), and skin (touch) that we use as external sensors to measure the world around us. Equally important are our internal sensors that allow for our ability to sense temperature, balance, pain, and provide a sense of where our limbs are at any given moment. Using all of that information, we are able to figure out what's around us, to orient ourselves, and allow us to (usually) successfully navigate our environment.

Robots are no different, except that the number and kinds of sensor that they have are much more varied. A fully equipped robot might sport external sensors such as bump, sonar, camera, distance, microphones, and chemical detectors, and internal sensors such as temperature, balance (gyroscope), and motor encoders. Most, however, don't need quite so many sensors. Rugged industrial robots might rely extensively on motor position encoders to play back pre-recorded movement patterns, with only a few external sensors, such as a camera, to correct for small alignment errors. Research robots designed to explore new environments, such as Honda's ASIMO and Stanford's Stanley , use a wide array of sensors to measure and react to their environment in as flexible a way as possible. Hobby robots usually fall somewhere in between, with the simplest versions using only a few touch sensors to navigate their world by brute force, and the most complex ones approaching the capabilities of research robots.

Some robots are designed using unique sensing apparati. For example, the SCRATCHbot, developed by a group of researchers from the University of Sheffield and the Bristol Robotics Lab, takes inspiration from a rodent. Rather than relying on light sensors or cameras (which don't work well in dark tunnels), it uses a whole array of sensitive whiskers to sense and navigate its environment.