Sensors,+probes,+real-time+data+collection

=__**Sensors**__ =

 A sensor is a device that measures or detects a real-world physical condition, such as motion, heat or light and converts the reading into an analogue or digital representation. Sensors receive and respond to external stimuli. Its sensitivity indicates how much the sensor's output changes when the measured quantity changes. For instance, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the sensitivity is 1 cm/°C. (So in layman's terms: The scale per unit input is the sensitivity of the sensor)

Sensors are often used as part of a [|feedback cycle]. They collect data continuously and are typically linked to a **control program** that specifies acceptable levels, eg the minimum and maximum temperature in a [|green house]. The control program decides what to do next based on the data it's fed by the sensors.

=__**Probes**__ =

Generally, a probe is an action taken or an object used for the purpose of learning something about the state of the network. For example, an empty message can be sent simply to see whether the destination actually exists. [|Ping] is a common utility for sending such a probe, and a //probe card// is a microchip placed in a circuit in order to test its signals. It can also be a program or another device inserted at a key juncture in a network for the purpose of monitoring or collecting data about network activity.

Relative to computer security in a network, a probe could be an attempt to gain access to a computer and its files through a known or probable weak point in the computer system.

=__**Real-time data collection**__ =

The sampling of the real world to generate data that can be manipulated by a computer. Real-Time really means “Within Time”. The ability to collect data automatically on demand, and have the data delivered and analyzed quickly enough to effect monitoring and control decisions.

Real life examples of the use of Real-time data collection:


 * PLC–(Process Logic Controller) a digital computer used for automation of electromechanical processes, such as control of machinery.
 * RFID–(Radio Frequency Identification)the use of a tag applied to or incorporated into a product, animal, or person for the purpose of identification and tracking, using readers that detect or produce radio waves.
 * CMM –(Coordinate Measuring Machine) a device for measuring the physical geometrical characteristics of an object.

//Samantha Beaumont// //Last edited: 12 October 2011//

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