Sensor Science and Technology to Analyze the Signals
Sensor OR Actuator detects & measures the signals. Classification of signals with examples into six categories based on energies generated & received, Detect & Measured by Sensor OR Actuator.
The explanation is based on INSTRUMENTATION ENGINEERING
Smart Sensor Block Diagram
What is sensor science definition?
- A physical device that detects and responds to some type of input from the physical environment. The specific input could be light, pressure, humidity, gas concentration, motion, Greenhouse effect and other environmental phenomena.It also is transmitted electronically over a network for reading or further processing.Such physical device gives measurable respond along with changes in physical conditions.
- Such physical device is to be said Sensor. This phenomenon of the sensor is known as Sensor Science.
What is sensor technology definition?
A Sensor Device detects the physical quality of signal and measures physical quantity of signal that is to be converted to human-readable analog or digital display in numerical value at the output. Implementation, Design of Mechanism and Calibration of the sensor device is to be done based on Explicit mathematical expression, table of data or well-defined scientific rule(s). Such Technology is to be said Sensor Technology. Analysis of specific signal’s characteristics, features can be done by using sensor device.
What is smart sensor definition?
- A) New sensing methods B) Improved computing capability & C) Digital communication New sensing methods mean, combined technologies and integration techniques of multiple sensors in latest updated version. Digital correction in new such techniques improves performance by,
1) Compensating for sensor non-linearity
2) Permitting a larger proportion of sensors to meet specifications
3) incorporating programmable gain
4) Changing sampling rate
5) Filtering quality must be very high for digital communication by removing noise & all errors to send error-free data signal(s).
Noise-free and the error-free desired output signal can be directly obtained by applying smart sensors, so it said to be Primary Sensor also.
Example of a Smart Sensor: FIX Smart sensor sends notifications to your mobile phone if arise any wrong in your automobile car.
Classification of Sensors OR Types of Sensor:-
- Mechanical and Electromechanical Sensors: The sensors which detect and measure the mechanical quantities, such sensors said to be Mechanical Sensors. Where physical input as motion, velocity, force, speed, displacement, torque and produced physical quantity such as electrical, magnetic, optical, thermal at the output, this output are measured values of mechanical input quantities (motion, velocity, force, speed, displacement, torque). Process variables like pressure, flow and level are also be considered as mechanical inputs and Mechanical Sensors are to be used for measurements such variables.
In many applications, such sensors ‘electromechanical coupling’ is involved. As such main purpose, convert input mechanical form to electrical output form for convenience of processing & display. Such sensors are termed as Electromechanical Sensors. In such cases, all electrical meters are calibrated in terms of mechanical measurand quantity at output section.
- Thermal Sensors: Thermal sensors are mainly temperature detecting & measuring sensors and such devices have operating principles have long been established, especially those of the primary sensors also called thermodynamic sensors. Any physical quantity say Q, expressed as its magnitude in number N and in unit U,
The equation expressed as Q=NU
If it is possible to relate temperature T can be measured directly in the form of equation Q=NU from the first principles, in a sensing system, then its to be said Primary Sensor. The Primary sensor’s principles are developed with newer innovations, improved quality, and better practical approaches. But many common practical ‘thermometers’ sensors can NOT sense/measure temperature directly following primary equation Q=NU. Those sensors are to be said Secondary Sensors.
As per instances, of a primary and secondary sensor is ‘Gas Thermometer’ and ‘Resistance Thermometer’ respectively.
- Magnetic Sensors: Magnetization serves a strong influence in changing the properties of certain materials. Magnetization changes or produces effects which are mechanical or electrical in nature as well as measurable. Optical energy can changes magnetization properties of the materials.Appropriate materials are to be chosen for optimum ‘Hall Mobility’ by using proper Magnetic Sensor. As an example, ‘Magnetoresistive Semiconductor Sensor’. Magnetic Sensors have so many applications to measure several kinds of physical quantities.
Another example: Proximity Sensors emit beam on the field and looks for changes in the field or return signal. By multiplication of beam velocity and transit time is the value of ‘distance measurement’ converted to human-readable display.
- Radiation Sensors: Radiation Sensors’ technology is the basis of fundamental laws of the photoelectric effect.Radiation energy producing through space in quanta when collides with matter, certain integral number of quanta called photons are emitted, reflected and others absorbed depending on the material properties. If the incident photon energy hv ( where h is Planck’s constant & v is the frequency of radiation) then,
hv= + —————Equation
Where kinetic energy of the electron & is the energy required to release the electron from the material.
( =constant charge of electron, = constant work function)
The work function is characteristic of the material.
Since the equation we get, the kinetic energy of photoelectron is dependent ONLY on the incident photon energy. If the incident photon energy is sufficient, then the electrical conductivity of the material increases. The changes value of the electrical conductivity is corresponding measured value of the ‘intensity of incident radiation’ display by Ammeter that calibrated in terms of radiation quantity unit at output section.
As examples, Photodetectors Sensor,Photoemissive Cell,Photomultiplier , Photovoltaic sensor etc.
- Chemical Sensors: The electrochemical cell consists of two electrodes (Anode & Cathode) immersed in suitable electrolyte solutions.If these electrodes are connected externally and internally by metal conductors so ion movement can take place between them.The electrodes are anode and cathode where oxidation and reduction respectively, take place. Oxidation and reduction are ‘interfacing mechanism’ where the ionic conduction of the solution is coupled to the electronic conduction between two electrode metals and hence, an electrical circuit is completed in a cell. The basic approach is to use a pair of electrodes in the analysis medium that sense / measure the chemical quantities, chemical actions and chemical reactions in the medium in the form of current, voltage, or power.
Examples, The pH Sensors, sense and measure the pH value of solids, liquids & gaseous chemical substances.
Active and Passive Sensors: The sensors those NOT required external power supply for operation, such sensors are called Active Sensors. The sensors those MUST require an external power supply for operation, mean such sensors cannot be done the operation without external power supply, such sensors are called Passive Sensors.