See-saw drop

A marble falls through the 'Plughole' and drops on to one end of the 'See-saw'. (Remember, the 'Diver' is on the other end.) This will activate a limit switch hidden under the 'See-saw' and so start off the next sequence. In practise, it was essential that the 'See-saw' remained depressed for about one second hence the retaining bent strips that are shown in the pic. How the limit switches are used will be explained more fully when we have a look at the 'works' both underneath and at the back of the model.