ANALOGUE JOYSTICK BOARD

Midwich has produced an analogue joystick board which fits both the ZX-81 and the Spectrum. It can take two joysticks by plugging them into two six-way DIN sockets on the side of the bare board. It is input/output-mapped and requires the use of a small section of machine code on the ZX-81.

The board uses a ZN499E A/D converter and a switch to select which direction to measure. The results vary from 0 to 255 for each direction on the joystick - N/S and E/W - and the "FIRE" button operates one bit each of a second port, one giving 0 or 128 and the other 0 or 64; the higher number indicates that the button is pressed. Both pressed gives 128 = 64 (191).

Inserting the power plug is difficult, as not sufficient space has been left between that and the joystick sockets on the Spectrum version.

Midwich sells the board as a kit for £17.20 and assembled for £22.95. The joysticks cost £4.50 uncased with fire button. The kits are well-designed with good instructions. Midwich Computer Co Ltd, Rickinghall House, Richinghall, Suffolk IP22 1HH. Tel: 0379-898571.

ADDING ON YOUR SPECTRUM

Our review team take a brief look at some of the hardware add-ons fir the ZX Spectrum.

Now that the ZX Spectrum has well and truly established itself on the micro market, it is amply supported by a wealth of hardware add-ons. Most of these peripheral devices have been manufactured by the people who supported the ZX81, but just as the Spectrum has attracted new users with its prowess, so too has it attracted a new following from the add-on manufacturers.

In this brief guide, we have not tried to cover all the devices currently available on the market but rather give you a flavour of the technology you can add on to your Spectrum. As joysticks are an obvious favourite, these have been covered in some detail whereas RAM packs are fairly standard and so have only been briefly touched on. Also included in this section area number of quite specialised add-ons like sound units and a digital tracer.

If you own a Spectrum, you will no doubt have begun to realise the potential you hold in your hands. Over the next few pages you will hopefully see further applications for you and your computer to explore.

This interface is once again not boxed. Good connections are made when the board is plugged into the Spectrum, but there were fears (unfounded as it happens) when it had to be removed. The Midwich interface lies horizontal out of the back of the Spectrum, rather than vertical like the rest of the review samples, and there were the nagging fears of the 'RAM pack wobble syndrome' happening all over again.

The interface board is available from Midwich as a kit, and as such comes complete with full instructions for assembly. Once you have completed its manufacture, there are also a number of programming suggestions which can be utilised to test the unit. Provision is made for two joysticks, and although the DIN plugs are used for a good connection, the board did not feel very safe whilst the connections were made. Removing the joysticks from the board involved some fairly vigorous manoeuvering as well, which did not feel very confident.

The joysticks supplied with the sample were fairly sturdy and held up well in operation. The feel of them was a little floppy, but they nevertheless worked adequately. The firing button, emphasised in bright red, operated whenever it was needed without any worries.

The cost of the analogue input interface is £22.95 and each joystick is priced at £7.99. For further details of Midwich products contact Midwich Computer Company Ltd, Rickinghall House, Rickinghall, Suffolk IP22 1HH.