Movement Sensors

This week was all about sensors and it was extremely interesting to see how many different sensors are available and used in everyday applications. This week I focused on movement sensors and found that the most used type of movement sensor is called a Passive Infrared Sensor, PIR. This sensor uses heat to detect movement within a given area. This sensor is used in automatic lighting schemes, burglar alarm systems, automatic welcome greetings and even motion detecting remote cameras (see video below). These sensors usually have a range of approximately 20 feet but will practically never wear out, are extremely reliable, incredibly cheap and simple to use.
I thought it was incredibly important to note, especially with the talk of data overload in recent classes the number of readings that single sensors are able to take. Both Junwah Ng , and Xiang Li talked about different senosors, humidity and pressure respectively, but both mentioned the number of measurements each of these sensors can take. Even though the PIR sensor is simple I am sure that there are a number of movement sensors that provide an abundance of measurements that can be recorded to help in disciplines such as traffic studies, population tracking, mass transit security and monitoring and many more. 

References:
http://www.gadgetshack.com/motionsensor.html
http://www.ladyada.net/learn/sensors/pir.html
http://www.instructables.com/id/PIR-Motion-Sensor-Tutorial/
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