Sensor
A sensor is something that is used to detect changes in the physical or chemical environment. The output variable from the sensor which is converted into an electrical quantity is called a transducer.
At this time, these sensors have been made with very small sizes on the order of nanometers. This very small size is very easy to use and saves energy.
Classification of Sensors are:
- Chemical sensors
- Physical Sensors
- Biological Sensors
What is a Chemical Sensor?
Chemical sensors detect the amount of a chemical substance by converting chemical quantities into electrical quantities. It usually involves several chemical reactions. Examples of chemical sensors are pH sensors, Oxygen sensors, explosion sensors, and gas sensors.
What are some examples of Physical Sensors?
In general, based on the function and use of physics sensors, they can be grouped into 3 parts, namely:
- thermal sensor (heat)
- mechanical sensor
- optical sensor (light)
What is a thermal sensor?
Thermal sensor is a sensor that is used to detect symptoms of changes in heat/temperature/temperature in an object dimension or a certain dimension of space. For example; bimetal, thermistor, thermocouple, RTD, photo transistor, photo diode, photo multiplier, photovoltaic, infrared pyrometer, hygrometer, etc.
What is a mechanical sensor?
Mechanical sensors are sensors that detect changes in mechanical motion, such as displacement or shift or position, straight and circular motion, pressure, flow, level etc. Example; strain gage, linear variable differential transformer (LVDT), proximity, potentiometer, load cell, bourdon tube, etc.
What is an optical sensor?
Optical or light sensor is a sensor that detects changes in light from a light source, reflected light or light refraction that hits an object or room. Example; photo cell, photo transistor, photo diode, photo voltaic, photo multiplier, optical pyrometer, etc.
Physical sensors detect the magnitude of a quantity based on the laws of physics. Examples of physical sensors are light sensors, sound sensors, force sensors, pressure sensors, vibration/vibration sensors, motion sensors, speed sensors, acceleration sensors, gravity sensors, temperature sensors, humidity sensors, electric/magnetic field sensors, etc.
What are some examples of Biological Sensors?
- molecular and biomolecular measurement sensors: toxins, nutrients, pheromones
- Sensors for measuring glucose, oxygen, and osmolality levels
- Protein and hormone measurement sensors become electrical quantities in which several chemical reactions are involved, such as pH sensors, oxygen sensors, explosion sensors, and gas sensors.
Before understanding and applying the use of sensors in detail, it is necessary to study the properties and classification of sensors in general. Sensors are electrical or electronic components, where the nature or electrical character is obtained or taken through electrical quantities (example: electric current, electric voltage or can also be obtained from non-electric quantities, for example: force, pressure which has a mechanical magnitude, or temperature is a quantity). thermal, and can also be chemical quantities, maybe even optical quantities).
Sensors are distinguished according to sensor activity based on signal conversion from non-electric signal value to electric signal value, namely: active sensors and passive sensors. The following is a picture of the nature of the sensor based on the classification according to its function.
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| Figure: The nature of the sensor based on the classification according to its function. |