The Safety Factor
The matter of safety cannot be emphasised too strongly. If you work in a school or other institution, there is probably a safety code for the use of electrical equipment to which you must adhere. Vibrating footspas would be wonderfully rewarding outputs, but they contain water, so they should not be used with switching systems. Light bulbs are hot, and will burn if they are touched.
The outputs in the suggested list above are all of low wattage - switching systems are not designed nor intended to turn on washing machines or electric fires. These are not merely issues of common sense - it is most important that you do refer to your health and safety regulations, and to the maximum output wattage recommended by the manufacturers of the switch Control Unit.
3) Other types of Output
Beside many public and private hand wash basins these days are automatic hand-dryer machines. They may be operated by proximity of the wet hand, or by button, but what a wonderful example they provide of a ready-made switching system with an interesting output! If the student can only reach just that little bit further, she is rewarded by a handful or faceful of warm air, which she might find very exciting.
Look around your local environment. Automatic doors in supermarkets are fun, until the manger comes to shoo you away. At the Royal Schools for the Deaf the workmen are fitting automatic doors for the pupils in wheelchairs to use. They operate from large metal pad switches in the walls.......as soon as the electricians have gone we are going to have some fun with those! And look around the steering column of your car - a veritable arsenal of switching systems.
There are switching systems all around us, but we don't notice them. I am not suggesting that you encourage your students to knock that little silver hammer through the glass of the fire bell, but, be honest, have you never been tempted by the emergency cord on an Intercity train?
Much of what has been discussed above refers to mains-powered effects brought into play by the tiniest movement of your student's hand, or by some other part of her body. Now, what about battery-powered equipment - torches, clowns that bang drums, dogs which go head-over-heels, alien ray guns with their flashing rainbow lights and their appalling noises of sirens and machine guns? Most of these can be adapted for use with switches, and you don't have to worry about safety, because they work from little batteries. They will work directly from a switch, or through a commercial Control Unit.
Later in this booklet I shall describe in detail the methods we use.