The activity is based on controlling a model of a driverless automatic train. The students work in pairs, they are given a wheeled buggy with an electric motor. There are a series of tasks that they have to control the buggy to perform. The tasks are split into five sections. In section 1 they use a pressure switch and electrical circuits, section 2 uses a slide switch, section 3 uses the outputs of a programmable electronic controller (IQ2 chip), section 4 uses the inputs and outputs of a programmable electronic controller. In section 5 there are various additional tasks using different switches, graduated in difficulty, which can be completed by students if they finish other sections early.
At the end of the second section the buggy should be going backwards and forwards between two fixed objects. In section 3 the buggy should be starting from station A, going to B, stopping then going to C, then reversing and stopping at B & A on the return journey. In section 4 the buggy should go to different stations depending on if it is daytime, has a passenger etc.
If time is limited you can start on section 2 or 3. With older groups it is tempting to miss out the first sections, but I have found that starting at the beginning helps to revise electrical circuits, it is then fresh in their minds for the later sections.
As I run this activity every year fifty plus times, it is worth me putting together a lot of kit. The students work in pairs so cannot avoid a very hand on experience of electrical circuits!