In the broadest definition, a sensor is a gadget, module, machine, or subsystem whose reason for existing is to recognize occasions or changes in its condition and send the data to different hardware, oftentimes a PC processor. A sensor is constantly utilized with different gadgets.

Sensors are utilized in ordinary articles, for example, contact touchy lift catches (material sensor) and lights which diminish or light up by contacting the base, other than multitudinous utilizations of which a great many people are rarely mindful. With progresses in micromachinery and simple to-utilize microcontroller stages, the employments of sensors have extended past the conventional fields of temperature, weight or stream estimation, for instance into MARG sensors. Besides, simple sensors, for example, potentiometers and power detecting resistors are still broadly utilized. Applications incorporate assembling and hardware, planes and aviation, vehicles, medication, mechanical technology and numerous different parts of our everyday life. There are a wide scope of different sensors, estimating concoction and physical properties of materials. A couple of models incorporate optical sensors for Refractive list estimation, vibrational sensors for liquid thickness estimation and electro-concoction sensor for checking pH of liquids.

A sensor's affectability shows how much the sensor's yield changes when the information amount being estimated changes. For example, if the mercury in a thermometer moves 1 cm when the temperature changes by 1 °C, the affectability is 1 cm/°C (it is fundamentally the slant dy/dx accepting a straight trademark). A few sensors can likewise influence what they measure; for example, a room temperature thermometer embedded into a hot cup of fluid cools the fluid while the fluid warms the thermometer. Sensors are typically intended to smallly affect what is estimated; making the sensor littler regularly improves this and may present different focal points.

Mechanical advancement permits an ever increasing number of sensors to be produced on a minute scale as microsensors utilizing MEMS innovation. Much of the time, a microsensor arrives at an altogether quicker estimation time and higher affectability contrasted and perceptible methodologies. Due the expanding interest for fast, reasonable and solid data in this day and age, expendable sensors—minimal effort and easy‐to‐use gadgets for short‐term checking or single‐shot estimations—have as of late increased developing significance. Utilizing this class of sensors, basic investigative data can be acquired by anybody, anyplace and whenever, without the requirement for recalibration and agonizing over pollution.