How Does an IoT System Work? | IoT Sensors

 How Does an IoT System Actually Work?

A complete IoT system integrates four distinct components: sensors/devices, connectivity, data processing, and a user interface.

1) Sensors/Devices

First, sensors or devices collect data from their environment. This could be as simple as a temperature reading.For example, your phone is a device that has multiple sensors (camera, accelerometer, GPS, etc). However  sensor  is used to collect from the environment by something.

2) Connectivity

Next, that data is sent to the cloud .

The sensors/devices can be connected to the cloud through a variety of methods including: cellular, satellite, WiFi, Bluetooth, low-power wide-area networks (LPWAN), or connecting directly to the internet via ethernet.

Each option has tradeoffs between power consumption, range and choosing which connectivity option is best comes down to the specific IoT application, but they all accomplish the same task: getting data to the cloud.

3) Data Processing

Once the data gets to the cloud, software performs some kind of processing on it.

This could be very simple, such as checking that the temperature reading is within an acceptable range. Or it could also be very complex, such as using computer vision on video to identify objects (such as intruders in your house).

But what happens when the temperature is too high? .

4) User Interface

Next, the information is made useful to the end-user  through an alert to the user (email, text, notification, etc). For example, a text alert when the temperature is too high in the company’s cold storage.

Also, a user might have an interface that allows them to proactively check in on the system. For example, a user might want to check the video feeds in their house via a phone app or a web browser.

Depending on the IoT application, the user may also be able to perform an action and affect the system. For example, the user might remotely adjust the temperature in the cold storage via an app on their phone. After this the temperature signal given to user it can be maintained by user. Thus the work of iot devices is only to indicate the user about the change in environment.

 IoT − Sensors

IOT sensor is one of the Hardware included in IOT. These devices manage functions such as system activation, action specifications, security, communication, and detection to support-specific goals and actions.

A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat,  moisture, pressure, or any one of a great number of other environmental phenomena.

The most important hardware in IoT might be its sensors. These devices consist of energy modules, power management modules, RF modules, and sensing modules. RF modules manage communications through their signal processing, WiFi, Bluetooth, radio transceiver,etc

The sensing module manages sensing through assorted active and passive measurement devices. Here is a list of some of the measurement devices used in IoT −

S.No	Devices
1.	accelerometers	temperature sensors
2.	magnetometers	proximity sensors
3.	gyroscopes	image sensors
4.	acoustic sensors	light sensors
5.	pressure sensors	gas RFID sensors
6.	humidity sensors	micro flow sensors

Wearable Electronics

Wearable electronic devices are small devices worn on the head, neck, arms, and feet.

Smartwatches not only help us stay connected, but as a part of an IoT system, they allow access needed for improved productivity.

Current smart wearable devices include −

• Head − Helmets, glasses
• Neck − Jewelry, collars
• Arm − Watches, wristbands, rings
• Feet −  shoes

Smart glasses help us enjoy more of the media and services we value, and when part of an IoT system, they allow a new approach to productivity.

Working of sensor

A sensor is a device that responds to some type of the input from the environment such as heat, light, motion, temperature, pressure and moisture. Sensors are used to switch currents and voltages. Every sensor has three terminals: Vcc, GND and output.

A sensor is a device that responds to some type of the input from the environment such as heat, light, motion, temperature, pressure and moisture. Sensors are used to switch currents and voltages. Every sensor has three terminals: Vcc, GND and output. Vcc is used to power up the sensor; to provide a fixed negative reference, ground is used, and the output of the sensor is analog. But in some sensors, there may be more than one output terminals.

Types of sensor

Active Sensors:

Active sensors are the type of sensors that produces output signal with help of external supply(voltage). The own physical properties of the sensor varies with respect to the applied external effect. Therefore, it is also called as Self Generating Sensors.

Examples: LVDT , SONAR, etc.

Passive sensor

Passive sensors are the type of sensors that produces output signal without the help of extern supply.

Example: Thermocouple, which generates a voltage value corresponding to the heat, applied. It does not require any external power supply.

Sensor Performance Characteristics

•      Transfer Function: The functional relationship between physical input signal and electrical output signal. Usually, this relationship is represented as a graph showing the relationship between the input and output signal, and the details of this relationship may constitute a complete description of the sensor characteristics.

•      Accuracy : Generally defined as the largest expected error between actual and ideal output signals. Typical Units : Kelvin.

•      Noise :All sensors produce some output noise in addition to the output signal. The noise of the sensor limits the performance of the system based on the sensor. Noise is generally distributed across the frequency spectrum.

•      Bandwidth : All sensors have finite response times to an instantaneous change in physical signal. In addition, many sensors have decay times, which would represent the time after a step change in physical signal for the sensor output to decay to its original value. The reciprocal of these times correspond to the upper and lower cutoff frequencies, respectively. The bandwidth of a sensor is the frequency range between these two frequencies.

•      Resolution : The resolution of a sensor is defined as the minimum detectable signal fluctuation. Since fluctuations are temporal phenomena, there is some relationship between the timescale for the fluctuation and the minimum detectable amplitude. Therefore, the definition of resolution must include some information about the nature of the measurement being carried out.

Actuators

•      Actuators are devices used to produce action or motion.

•      Input(mainly electrical signal , air, fluids)

•      Electrical signal can be low power or high power.

Another type of transducer that you will encounter in many IoT systems is an actuator. In simple terms, an actuator operates in the reverse direction of a sensor. It takes an electrical input and turns it into physical action. For instance, an electric motor, a hydraulic system, and a pneumatic system are all different types of actuators.

Types of actuator

•      Hydraulic actuator : Hydraulic actuator consists of cylinder or fluid motor that uses hydraulic power to facilitate mechanical operation.

Mechanical motion gives output in terms of linear, rotary or oscillatory motion.

 Hydraulic Actuators are used in industrial process control, employ hydraulic pressure to drive an output.

•      Pneumatic actuator

•      Mechanical actuator

•      Electrical actuator

•      Piezoelectric actuator

•      Thermal/Magnetic actuator