SPECTRUM SWITCHES ON FOR DOMESTIC DUTIES

One of the more unusual offerings from the Spectrum chain of shops is the Domestic Controller by Indescomp for the Spectrum. It is an I/O port with four relays built in and four input channels.

The relays can control low-powered equipment such as battery-powered devices or, for example, with the inputs as part of a burglar alarm circuit, the input detecting windows and doors being open and the output opening doors and turning lights on and off. Equally, users who are building a robot, with all its associated in/out requirements will find it useful.

Each relay can switch up to one amp. No details of voltages are given and the input can detect a voltage of between 4W and 50V. Connections to the unit are by screw terminals and a LED is used to show which channels are in use.

To control the unit address 61441 is used, the lower four bits controlling the output and the upper four the input. With issue 3 Spectrums, due to the changes, the input may vary by seven, i.e., the lower four bits, but a program is included to allow for that.

Other than that the unit is very easy to use, especially if you have a knowledge of binary. Its only disadvantage is that the relays are not marked as being suitable for mains use, which limits its applications.

The Domestic Controller costs £49.95 and is available at Spectrum shops.