The buffer box is connected up to the user port and the printer port at the back of the BBC Master 128 computer. The buffer box then provides powerto lights, motors, buzzers, etc., all of which can be switched on/off using a software package. For this, I used the software package Contact from NCET - a simple LOGO-type control language for primary schools. The package provides Switchon, Switchoff Repeat, and Wait commands, as well as the facility to build and edit procedures.

To the lighthouse
A TV programme in the BBC Science Challenge series provided the starting point for our classwork. This programme dealt in an imaginative and very effective way with batteries, bulbs, and circuits, and offered my pupils the challenge of making a model lighthouse with a light which actually worked. The pupils worked in groups of 3, using mineral bottles topped with bulbs in bulbholders. The bottles were attached to wooden bases, and the assembly then painted. Two wires from the bulbholder terminals passed through the bottle, emerging at the base. When these wires were attached to the battery-poles, the bulb lit up. However, the limitations of this arrangement soon became apparent. At that point I suggested we try using the computer to make the lighthouse more realistic.

The buffer box has eight sets of sockets. The two wires from the lighthouse, instead of being attached to the battery, are inserted into a pair of sockets on the buffer box. This socket pair is numbered, and controlled by the software. Type in 'Switchon 1', press RETURN, and the lighthouse plugged into socket number one lights up. Now type in 'Switchoff' , and the light goes out. By this means, eight different lighthouses can be attached at the same time.

Procedures
When pupils had experimented with this for a time, I introduced the idea of a procedure. This operates in the following way:
¥ type in a list of instructions
¥ give this list a name
¥ the computer will remember the list and execute the instructions Nhen the procedure name is typed in.
fo make the procedure recursive (i.e. carry on ad infinitum) the Drocedure name is itself inserted as the last line of the procedure. rhis means that the computer carries out the full list of instructions again and again, each time it meets the procedure name. Here is an example:
TO LIGHT
Switchon 2 (Switches on socket number 2)
Wait 3 (Waits 3/60 of a second)
Switchoff 2 (Switches off socket number 2)
Wait 3 (Waits 3/60 of a second)
LIGHT (Starts again)

Pupils enjoyed this immensely. Soon they were writing procedures to turn on/off two, three, and even more lighthouses, giving each lighthouse a different pattern. Finally, we wrote a procedure to operate eight lighthouses. The whole class co-operated in editing and improving this procedure, which was then saved.
Green light
Our next challenge was to construct a working set of traffic lights, and then to write a procedure which would operate them in the correct sequence. This required close observation of the local traffic lights, and a recording of their sequence on paper. Timber, bulbs, bulbholders, and wires were used to construct the traffic lights. A base was made of cardboard, and painted to show the road junction. The lights were correctly positioned, and the wires brought to the control (i.e. buffer) box. Writing a procedure for the traffic lights was a little more difficult and required a certain amount of teacher help. Eventually, pupils completed their task. The school principal was very impressed when one of the pupils typed in 'Traffic' (the procedure name), pressed RETURN, and the set of traffic lights began to operate!

Student Fair
We decided to exhibit our work on lighthouses and traffic lights at the CESI (Dublin Branch) Student Computer Fair (at The Marino Institute of Education, March 28th. 1992). You can imagine our surprise and delight when our project was awarded a special prize by Lendac Data Systems Ltd.., one of the Fair's commercial sponsors.

Ourselves
After our work on Control Technology, we had little time left to use
other programs. We did however use Facemaker (one of the 'Best
Four Language' set from ESM) and Our Facts (a database from
NCET) as part of a project on 'Ourselves'.
In Facemaker, pupils are asked questions about the appearance ofthe person whoseface is to be drawn. Using pupils' replies aface is constructed, and using Screenprintscreendump from ESM, the face can then be printed. Using Facemaker, each pupil 'drew' a portrait of himself and one of a parent.
With Our Facts database, we first discussed the ten headings we should use to build the database. As a result we chose: ADDRESS, AGE, MONTH OF BIRTH, HOUSE TYPE, PET, HEIGHT, WEIGHT, HAIR COLOUR, MEANS OF TRAVEL TO SCHOOL, NUMBER OF CHILDREN IN THE FAMILY We then discussed and standardisedthe possible entries. Next, pupils in pairs entered in their data. When all the data had been entered, pupils edited the entries to correct mistakes. Pupils were then shown how the database could be used to draw graphs based on our data, and to answer questions like: how many pupils come to school by bus? or how many pupils who live in semi-detached houses have a dog for a pet? Then, working in pairs, pupils had the opportunity to use the database in this way, and to print out any graphs they wished.

This completed our computer, work for term 2 of the school year. Our class has the use of a BBC Master 128 for four days every second week.