One of the Attainment Targets, AT 12, in the National Curriculum for science specifies that data collection and control should span key stages 2 to 4. For control this amounts to turning on a DC motor, a light bulb, buzzers, alarms and so on. These can be performed quite easily using ordinary switches to close a simple circuit, or with some dedicated electronics, to turn on after a time delay, or in response to specified external events.