Sensors are all around us and are growing in importance to monitor and control processes or devices. In essence a sensor is generally a device that turns a physical or chemical parameter into an electrical or digital output. Their role is to enable us or a computer or device to measure something useful such as temperature, pressure, position etc. Ideally they have outputs that are easy to use and easy for a computer to read.
So if you want to, say, monitor the temperature inside a container lorry transporting goods that need to be kept at a constant temperature, then a temperature sensor will be an important part of the control system. The sensor will provide an output that is proportional to the temperature and then this output can be easily converted into a number that represents the temperature (eg 12 deg C or 120 deg F etc).
We have sensors embedded in our bodies. So our eyes see colour and can detect movement etc. , our ears detect sound, our skin can detect temperature etc.
In other posts in this series we will explore typical sensor types used in manufacturing processes.