In the broadest definition, a sensor is a device, module, or subsystem whose purpose is to detect events or changes in its environment and send the
information to other electronics, frequently a computer processor. A sensor is always used with other electronics, whether as simple as a light or as complex
as a computer.
Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base, besides innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms, the uses of sensors have expanded beyond the traditional fields of temperature, pressure or flow measurement.
Moreover, analog sensors such as potentiometers and force-sensing resistors are still widely used. Applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life.