FAQS! FACTS! FAX! 026 (08/10/96)

PCS IN CONTROL?

I’ve come across several references regarding the use of computers, to control home appliances, but few hard facts. Can you tell me how easy, or difficult it would be to connect my computer to various devices as I’m interested in the idea of home automation. What extra hardware and software do I need, and how much does it cost?  

P.M., Winchester

A

It can be done, but conventional home and office PCs do not have any facilities to control external equipment, other than standard computer peripherals. You will need a controller card. This fits into a spare expansion slot on almost any IBM compatible PC.  It acts as an interface between the PC, and the outside world, usually via a switch or relay board, that can handle the higher voltages and currents needed to operate mains-powered devices.

There’s virtually no limit to what can be done, with the right software. For example, you could use your PC to control central heating and security systems, switch lights on and off at preset times, even wake you in the morning with an alarm call and a cup of tea. PC control of systems and machinery is commonplace in manufacturing industry, however, this is not an area the home PC market been overly concerned with to date, so there are no simple off the shelf solutions. There are several useful books on the subject: Micro Interfacing Circuits by R.A.Penfold, and Microcomputer Interfacing by Joseph J Carr, are a good place to start. They’re both available from specialist book shops, or Maplin Electronics, who also market a range of PC controller and switch boards, with software. Prices for controller boards start at around £80.

Contact: Maplin Electronics (01702) 554161

WAIT OR BUY?

I have a well-specified 486/100 PC that I would like to upgrade with a CD ROM drive. However, I understand a new system with even greater storage capacity is about to be launched. Should I wait, or buy a CD ROM drive, even though it could soon be obsolete?

D.F.T., Penrith

A

You’re probably thinking about DVD or Digital Versatile Disc, which has around six times the capacity of current CD ROM discs. It is coming, and one day it could even replace CD ROM, but that will take several years. Right now CD ROM drives are exceptionally cheap. Fast 4-speed models, suitable for the thousands of reference, games and multimedia titles currently on sale, are being advertised for as little as £40 in computer magazines. You will also need a sound card, they cost from around £25 upwards. If you’re handy with a screwdriver you can easily fit these components yourself, or have your local PC dealer to do it for you, for a small fee. Why wait any longer?

EYES RIGHT?

With reference to your reply to the reader with poor eyesight, looking for a high contrast monitor (Sites for Sore Eyes FFF 10/9/96), are you aware of a product called Compulenz? This fits over the front of the monitor and magnifies the whole screen. It’s available from Specialist Optical Source Ltd, (01753) 888411.

J.P.W., Gerrards Cross

MORE EYES

Monitors based on Sony Trinitron technology provide contrast rivalling high quality black and white monitors. Having used Apple’s Trinitron-based Macintosh colour display I could not go back to using a conventional monitor. Apple also provide a free extension with all Mac PCs, called CloseView, which magnifies the contents of the screen. It can also invert the display -- white on black -- for better contrast.

P.H., Birmingham

FINAL EYES

I too have had problems adapting to a PC screen, after changing from an Amstrad PCW, with a green screen. My solution was to continue to use PCW Locoscript, in its advanced PC form. A feature of this software is to allow the user to choose the colours for the background and text. After lengthy trials I have found green on black -- the same as the PCW display -- is the most satisfactory.

R.M.B., Richmond

A

Thanks to everyone who contacted FFF with suggestions and tips for making PC screens easier to read.