Sensor

A sensor is a device that receives and responds to a signal or stimulus. It detects changes in its environment and converts them into an electrical signal that can be understood by other devices, often a computer.

Sensors are used in many everyday objects. For example, touch-sensitive elevator buttons use a tactile sensor, and some lamps change brightness when you touch their base. They are also found in cars, airplanes, robots, and medical equipment.

With advances in small machinery and easy-to-use computer chips, sensors can now do much more than just measure temperature or pressure. They are used in many new ways, such as detecting movement, light, and even chemicals.

Sensors can be very small, made using special technology that builds them on a microscopic scale. These tiny sensors can measure things faster and more accurately than larger ones, and they can be used for short-term monitoring or one-time measurements.

Classification of measurement errors

A good sensor should be able to detect the specific thing it’s meant to measure, ignore other factors that might interfere, and not change the measurement itself. Most sensors work in a straightforward way, where their output changes evenly with the measurement. For example, a temperature sensor might produce a certain amount of electrical signal for each degree of temperature change. To understand the sensor’s output in real-world terms, we often need to adjust the numbers slightly.

Sensors aren’t perfect, and a few common issues can affect their results. Sometimes the sensor’s output can hit a maximum or minimum limit if the measurement goes beyond what it’s designed to handle. Other times, the sensor might give slightly different results depending on past measurements, or it might show small random changes over time. These differences can come from many sources, like temperature changes or tiny amounts of “noise” in the signal. By testing and adjusting sensors, we can often reduce these errors and get more accurate measurements.

Chemical sensor

A chemical sensor is a special device that can tell us what chemicals are in liquids or gases around it. It works by changing the chemicals it finds into a signal we can measure, like a light or sound. This helps us know how much of a certain chemical is there.

Chemical sensors have two main jobs. First, they recognize the chemicals by using special parts that stick to them. Then, they change this recognition into a signal we can read. Some of these sensors use living materials, called biosensors, but they can also use made-up materials that act like living ones, such as special plastics or tiny molecules.

Main article: Biosensor

Biosensor

Main article: Biosensor

In medicine and technology, special sensors called biosensors detect important substances using parts from living things, like cells or proteins. These sensors are different from other sensors because they include biological materials. They can be used both outside and inside living things. The biological part is protected inside the sensor, often using thin barriers or special materials, to help it work properly.

Neuromorphic sensors

Neuromorphic sensors are special devices that copy the way living nerves work in our bodies. They are built to act like real nerve cells, helping machines "feel" and react to changes around them. One example of this type of sensor is the event camera, which can quickly notice and send information about movement or changes in light.

MOS sensors

MOSFET sensors were developed after the invention of the MOSFET between 1955 and 1960. These sensors are used to measure many different things, like physical, chemical, biological, and environmental conditions.

There are many types of MOSFET sensors. Some are used in medical tools to detect things like DNA, blood markers, and glucose levels. Others are used in cameras and mice computers. These sensors are also used to monitor homes, offices, farms, traffic, weather, and even to check air quality and temperature.