What is Actuator

Throughout the history of computing, there has been a trend for the ratio of processing elements to people to increase, resulting in the creation and popularization of new usage paradigms. At the start of the modern computer age, many individual users shared a single mainframe in one central location. In the early 1980s, however, significant developments in microprocessor technologies ushered in the desktop era, resulting in a one-to-one correspondence between individual users and their computers. Computer resources were now intrinsically distributed. The growth of the internet allowed these resources to connect to each other. The pervasive computing paradigm is the next logical stage in this trend, resulting in the original computer-human ratio reversing, so that multiple computational devices are available to each individual user. In reality, this point was passed a number of years ago. Mobile phones, personal digital assistants (PDAs), portable music players, as well as numerous embedded devices that people now take for granted, has resulted in computing technologies being embedded into the fabric of everyday life. Thus, for the first time, the desire of computing resources being available on an anywhere, anytime basis is a realistic objective. In addition to computing being available everywhere, pervasive computing has a second key element. This tenet states that user interaction with these universal computing elements should occur in as natural and intuitive a manner as possible. Thus, pervasive computing technology should be assimilated transparently into the user’s natural environment. Rather than deal with the entirety of this broad topic, the focus of this article is to provide an overview of the key developments on one particular technology which is essential to the realization of the pervasive computing vision: the wireless sensor network.