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Internal sensors collect data from IoT consumer devices, such as security systems, smart appliances, smart TVs, and
            wearable health meters. Data are collected from commercial devices, as well, including commercial security systems,
            traffic monitoring devices, and weather tracking systems.

            IoT connects a variety of sensors, alarms, cameras, lights, and microphones to provide 24/7 security—all of which can
            be controlled from a smart phone. For example, the Ring doorbell camera security system permits users to see, hear,
            and speak to visitors at their door via a computer, tablet, or mobile phone.
            When you are at work, the lights may turn on using a motion sensor. Public toilet flushes often use a push-button or

            an infrared switch. You may also use a computer which uses many different sensors.
            Sensor can rather be called as transducer. A transducer is any physical device that converts one form of energy into
            another. In case of electronic devices, a transducer is a device that is used to convert a non-electrical signal into an
            electrical signal.

            So, in the case of a sensor, the transducer converts some physical phenomenon (mostly in analog form) into an
            electrical impulse that can then be simply converted in digital form for sending signal to controller for controlling
            intelligent devices or physical phenomenon. A microphone is a sensor that takes vibrational energy (sound waves),
            and converts it to electrical energy in a useful way for other components in the system to correlate back to the original
            sound.
            The actuator is just reverse of sensor. In most of the cases, it takes electrical signal and actuates a mechanical device

            for automation purpose.
            In a typical IoT system, a sensor may collect information and route to a control center where a decision is made and
            a corresponding command is sent back to an actuator in response to that sensed input.


                               Sensor     Networking     Control Center     Actuator        Process
                                       °C    Device                                         Control



                              Temperature    Sends this    Control center
                             sensor detects    detected signal   Internet  sends command to   Internet  Sprinkler turns
                                 heat.    to the control    sprinkler                   on and puts out
                                            center.                                        flame.
                             Fig. 4.2. Working of a typical IoT system for Process control (Automation)

            In general, these devices, and especially sensors, are used both in industry and research to collect data in various
            application contexts, like healthcare, environmental monitoring, and agriculture.

            Sensors are connected through gateways, which enable them to transfer the gathered data to a server in the cloud.
            Later, the information is transferred to computer or cell phone so you have an instant access to all monitored activities
            happening.
            Smart thermostats have become a common item for households—these tools depend a lot on data, captured by

            temperature sensors. Security systems, smart plugs, etc. all use IoT for data collection to ensure energy-efficiency,
            and in-house security.
            Safety sensors in mining operations can generate up to 2,4 terabits (TB) of data every minute. Sensors in one smart-
            connected home can produce as much as 1 gigabyte (GB) of information a week.






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