There are many areas of our life that are affected by control systems. Often they are hidden and we don't even notice them, but they are there, running a software programme and using hardware to make decisions that ultimately help us.

So what is a control system?

In simple terms the label 'control system' is used to mean a device or set of devices whose main purpose is to regulate, direct, manage and command the way other devices operate. That sounds very complicated but it is not.

Let's think a simple everyday example. 100 years ago if you wanted to take a bath you heated pots of water on an open fire and poured the boiling water into a large metal tub. It was not uncommon for people to get scalded as the water was very hot and the only way to check the temperature was to put part of your body in! Fast forward to now and the process has moved on dramatically. If we want a bath today, we simply turn on the hot water tap and fill the bath tub. In most houses we do not fear too much being burnt by the water as it is usually controlled to be no more than a certain temperature – how does it do that?


The way it works is that we now have boilers that heat our water. When the water setting is switched on, the boiler will heat a tank of water. It will continue to heat that water while an electronic device, known as a thermostat, monitors the temperature. When it reaches a certain temperature the heating element is switched off – in this way the water never becomes too hot and in danger of burning us. If we do not use any of the water it will slowly cool down. When it drops below a certain temperature, the thermostat again recognises this and switches the element back on to heat it up again. This way, we have hot water even a few hours after having initially turned it on. The thermostat is controlling the system – we do not need to remember to switch the water heater on and off whenever we want water or to save money on the heating. The heating system computer does it for us.

In most houses, this is only a small part of the clever computer that makes up the heating system for the house or flat. Usually the boiler will heat radiators around the house, these too can be 'programmed' to switch on and off at certain times of the day. Again, once programmed, the system will continue without the person living there having to do anything. They will even have safety features built in, for example if it is a gas powered system and the water pressure drops, which could indicate a gas or water leak, the sensors which are constantly monitoring it will recognize this and shut the system down. That way any problem doesn't get worse and the person doesn't come home to a flooded house or a gas explosion! This is quite a complex system of components all controlled by a computer brain and we don't even notice it's there! It is only one example of the many control systems we are surrounded by every day.

Why do we use computer control?

The main reason we use computer controlled systems is to allow us to control activities without the need for a human being to be present. They can be simple or very complex. They rely on a number of pieces of hardware and sensors of all different kinds can be used. What controls the system is the software or programme that takes the input from the hardware and makes decisions based on it before adjusting its output accordingly.

Control technology has enabled us to build simulations of situations and predict what might happen, to explore places we've never been able to go to safely before, take menial jobs that people didn't want to do and be performed for us by computers as well as create 'smart houses' and 'smart cars' that remove human errors from situations.