REDS UNDER THE BED - AND IN THE HALL
Finding truly useful purposes for computers in the home is a quest with rich rewards for those that succeed.
Chris Curry, one of the founding fathers of Acorn, has dusted off the concept of controlling the home environment and de- voted considerable skill to marketing the idea - the result is a system called Red Boxes.
The idea is you use your Spectrum to control the system which switches on and off lights, other electric things and detect's burglars etc, etc.
For £130 you can purchase a neatly packaged Red Boxes Starter Kit containing three of the aforementioned Red Boxes, a concise instruction manual and a connecting lead.
Red Leader plugs straight into the mains supply and is attached to your Spectrum via the Ear and Mic sockets, while. Red One and Two are simply plugged into any power socket in the house. Read Leader sends pulses round your house wiring to talk to Red One and Two.
Red Leader contains what can be described as a minimalist microcomputer - a 6502 CPU and 6520 support chip, backed up by a 16K Eprom and 8K of static C-MOS Ram. The rest of the board holds circuitry for communicating with the Spectrum and with the other Red Boxes by transmitting signals around the power ring main of your abode.
Red One is a power relay capable of switching on and off any mains-operated device plugged into its 13 amp three-pin socket. It plugs into any mains socket, and then the appliance you want to control plugs into Red One. Red Two contains an infra-red sensor of the type used by modern burglar alarms. Heat producing objects - like humans or an inferno - trigger it whenever they move into its field of view. Both devices contain somewhat simpler circuitry to Red Leader, but include an encoding system that gives every Red Box its own encryption number.
As Red Leader is a computer in its own right, it only needs the Spectrum as a terminal, fetching key-presses and sending characters to be displayed on the screen. For this to happen, a terminal emulation program must be loaded, which is achieved rather neatly: you enter Load "" and then switch on Red Leader, which pretends that it is a cassette recorder, sending the program to your computer.
With the Spectrum acting as a 'dumb' terminal, the system is rather reminiscent of an old teletype - very slow and accompanied by an irritating noise as the Spectrum's speak- er loudly echoes the conversation between the computers. Once programmed Red Leader can be left to its own devices, freeing your Spectrum for other use.
With the terminal software loaded, you get a menu-driven controlling program. An on-screen clock is provided along with the control options.
First you have to install each box by informing Red Leader of its type and code number. Boxes can be set On or Off or times entered when they are to be switched. Another option allows you to associate one box with another so that if the infra-red sensor is triggered, a lamp lights (so that burglars can see where they are going?)
At this point I discovered that my Red Two box was not transmitting back to Red Leader although the LED mounted on it seemed to indicate that it was sensing movement: quality control rather than the transmission system seems to be to blame for this, as Red One worked perfectly.
A few extra commands allows you to Save and Load data and so forth. In this mode you can do little more than you could with a £15 time switch and a burglar alarm, but extra programming power is avail- able if you quit the menu and use the Red Leader's own language called, predictably. Red Basic.
With 16K of Rom space avail- able you might expect Red Basic to be more sophisticated than it is, but many of the statements and functions on offer are ideally suited to control applications: Every is an interrupt-driven structure that instigates actions at fixed time intervals; When constantly monitors the remote devices and responds accordingly. Repeat Until and error trapping are available, along with custom commands such as Tell for controlling devices. Graphics commands are also provided, but these seem rather superfluous.
I would rather have been given some editing features in order to avoid the retyping of whole lines to correct the many syntax errors which I generated - error reporting is cryptic and the need for brackets and quotes rather inconsistent.
I soon had lights flashing on and off at all hours, but there is little that can be done with one relay and one non-functioning sensor.
Given more devices including such things as dimmers and temperature sensors you could set up your home to run with- out ever leaving your armchair, if that idea appeals to you, but taken note that each extra box will cost you £40. Equipping each room with controlled lighting, heating and electric curtains could cost a fortune.
It's all neatly engineered, though, and removes many of the problems normally associated with home control.
But I doubt if even the sharp marketing image will persuade many people that it is truly useful.