3 Major Types of Sensors

Sensors are intended to detect a change in a wide range of events or quantities. Most sensors are built to produce an optical output signal or electrical signal after detecting a particular type of input. There are many different sensors to match specific functions and applications.

Here are three of the main types of sensors:

Temperature

One of the most common types of sensors is those made to measure temperature. Thermostats are certain to feature in the home and used to detect and control the temperature of ovens, air conditioners, refrigerators and heating systems. Industrial sensors are standard in data centers and laboratories. There is a wide range of temperature sensors, but most are passive units, such as thermistors, RTDs and thermocouples. Thermocouples are the most cost-effective option. They are straightforward to use and are not dependent on an excitation signal.

Pressure

Pressure sensors feature in a wide range of manufacturing and industrial systems. The sensors are used to control and measure fluid, gas or air pressure. Most are built using quartz or piezoelectric sensors. They are built to detect many different types of pressure, such as gauge pressure (atmospheric conditions), differential pressure (pressure between two points), or absolute pressure (similar to a vacuum). The analog outputs are built to measure current, such as 4-20mA, or voltage, such as 1-5V. The output information can vary to match the specific situation, and includes PSI, kg/cm2, or bars.

Even though the pressure sensors are mostly used in industrial systems, they also feature in designs for a wide range of consumer products, such as automotive seats and mattresses.

Capacitive

Capacitive sensing has seen a significant increase in popularity in recent years with the development of touch screen devices, such as smartphones and tablets. However, it has previously been used to detect material properties, humidity and fluid levels. This type of sensor is made using multiple layers and connects to a circuit board. The sensor has the ability to detect the location or movement of the finger on the screen. It is only able to detect capacitance related to the skin, and isn’t intended to work with fingernails.

When it comes to controlling capacitive sensing, the fingers do not come into direct contact with the sensing unit. A great benefit of this is the low risk of mechanical wear after regular use. Any onscreen movement is sensed by an IC. This information is digitized and passed on to a microcontroller to let the smartphone complete the particular action.