Typically sensors measure liquids and gasses as they expand or contract. A sensor will give a reading of the force being exerted by a container to prevent the liquid or gas from expanding. The sensor acts as a transducer emitting a signal of the force being exerted. In most cases the signal is electrical in nature.
The principle of resistance is often employed. This means that a charge of electricity conducted through a material emits a signal that can be indicative of a particular reading. It is measured when the charge is passed through a wire.
A very wide variety of transducers are employed in a multitude of uses every day. They may also be known by other names such as manometers, among others. Many manufacturers produce many different devices designed to meet specific needs.
Essentially devices can be used to measure two dimensions. Weather instruments, car instruments, aeroplanes and such machines make good use of pressure transducers. Other instruments that are designed to measure forces at altitude are useful in things like hot air balloons and rockets.
With the development of technology sensors play an important role in improving the quality of life for ordinary people. In the past it was not possible to determine when a car was getting a flat tyre. The driver usually had to wait until violent swerving indicated a problem. He would then stop his car, get out and survey a mangled mass of shredded rubber hanging around the wheel. The invention of gadgets to measure tyre inflation in advance and warn of safety risks is just one small invention that helps to improve quality of life. There are many other examples.
One recent invention that has important implications for the individual is the blood pressure sensor. It helps to secure the health of patients who suffer from invasive blood problems. Sensors are now available to enable sufferers from blood disorders to detect dangerous changes in their own blood and take timely action. Another useful application is the use of transducer placed in the inner sole of a shoe. The data gathered can be sent to a mobile phone in the near proximity. Information thus gathered can help to analyse how stress is applied to feet and can help athletes and also people suffering from foot problems.
With the recent momentous advances in technology the question quite often arises as to whether people drive technology or technology drives people. Many people are bewildered by the rate of advance that seems to threaten the ability of ordinary people to cope with technology that is almost beyond control. In this scenario the pressure sensor is a comfortable technological monitor which quietly signals that it may be time to control a machine before it explodes or runs maniacally out of control.