What is a sensor?
A sensor is any hardware component that can gather data from the outside world, like touch, light, motion, audio. Pleo is able to use input from all of his various sensors, such as his camera, microphones and touch sensors, to make more intelligent decisions about how to react to the world he finds himself in.
One sensor can be used to monitor one thing. I.E. If you need to monitor five pages on a website you will need five sensors. Similiarly if you need to monitor a single page on five different websites you will also need five sensors. One sensor could also be used to monitor one FTP server, one SMTP server or one POP3 server.
