Sensors convert a physical parameter into an electrical signal, which may then be used as informational input into a process or display. Several types of sensing devices are in the Electronics and Sensors side of the Kinetics and Electronics Display Case for interactive viewing.

Some parameters which may be sensed are listed below along with the type of transducer used for detection.

A note on nomenclature. We see the words sensor, transducer, and element used together from time to time, and should clarify their meanings here. Transducers change some measurable parameter, like energy or force, into some other parameter. A photocell changes light intensity into electrical resistance, which can then be measured and acted upon by a circuit. A loudspeaker changes electrical waveforms into acoustic waveforms. They are both transducers. The term sensor is being used more and more frequently to describe the "cooked" example below. If you were to make a "smart" photocell which was computer-ready, it would have microcontroller on it, and the collective circuit would be a sensor. (There are a number of reasons why a smart photocell would be a bad idea, however.) In industry they would use the term element to identify the photocell per se, and sensor for the whole package. At SAIC, we use a lot of raw transducers and build our own conditioning circuits to bridge the element into the rest of the art piece.

Sensors can be used in different ways. The support circuitry around a transducer will be specific to the type of sensor and the and the device to which the sensor is connected. A door chime in a retail shop, or a thermostat on a furnace are examples of "raw" application.

The load cell in a digital postal scale, or the accelerometer in an automobile air bag will typically have its output more rigorously processed before it goes into a computer. You could say the "raw" output is "cooked" in the example below.

In the Kinetics Lab, we keep a few types of inexpensive sensors and transducers. Some examples are: photocells, thermistors, force sensing resistors, microswitches,  flex gages, sonar units, and IR motion detectors.