INDEPENDENT JOYSTICK

Voltmace has launched its new joystick - the Delta 3S. Unlike most joysticks it features two independent fire buttons, one of which can be used by either left- or right- handed players, and rotary switches are used on the stick. Those switches give it a very light action and the stick can be comfortably held in the hand.

Together with the joystick Voltmace is marketing two interfaces. One, made by Rainbow Electronics, is hardware-programmable and the other, from Cambridge Computing, requires software. The Rainbow interface also incorporates a beep amplifier. The stick has a standard nine pin Atari-style plug and so will work on any interface.

Priced at £10.00 the joystick is good value and its solid construction should ensure it outlives most competitors. The Cambridge Computing interface costs £22.95 - £29.95 with joystick - and the Rainbow interface is £29.00 - £37.00 with joystick. All prices include VAT and p&p. They are available by mail order from Voltmace Ltd, Park Drive, Baldock, Herts SG7 6ES.

INTERFACITS - JOYSTICK INTERFACING INVESTIGATED

A comprehensive round up of the units available - checked out by our team of reviewers.

One of the first add-ons that a computer owner may contemplate buying is a joystick of some kind. The increase in control that this provides is of obvious benefit to the dedicated games player. In addition it is becoming increasingly necessary for some of the complex graphics packages that are appearing for the Spectrum. However if you have not yet taken the plunge and are now contemplating the purchase of some form of controller you have a difficult choice ahead of you. In essence, most of the actual joysticks are very similar, and your eventual purchase will be based upon personal preferences for shape, size, ease of use etc., but the biggest decision to make will be that concerning the vital link between your joystick and the computer i.e. the INTERFACE.

Interfaces allow the use of joysticks with compatible software, and although there is a great variety of material available for use with all the more common interfaces no single one will give you control over every game, unless, of course you opt for a PROGRAMMABLE INTERFACE. These claim to give you joystick compatibility with ALL software.

This interface has a through-port at the back which is very useful for using other units like speech or sound devices. The unit also has a lip on the front to help prevent "wobble" but if you have a non-standard keyboard it gets in the way.

There is the usual nine pin plug on the left hand side for the joystick and the overall size is 11.5cm x 3.5cm x 7.5cm.

To use the interface you have to load a tape first which programs the interface to respond to the appropriate keys. If the game you're using fails to give this information on the instructions then you have to load the game first to find out! However once you have programmed a set of key-sequences, they can be saved on tape (the reverse side of the tape has been left blank for this purpose and provision is also made for saving to microdrive) and many games can be saved at one time. You are able to check the joystick position at the end of the programming sequence.

This interface is sold complete with a joystick and tape - the joystick is available separately and is reviewed as such.

The interface is a bit fiddly to use but has proved compatible with all software tried, but when an option of joystick or keyboard is offered from within a program, you must use the keyboard one as the joystick option frequently does not work.

STICKING WITH ADJUSTABLES

There are now several different ways of hanging a joystick on to the Spectrum, and they fall into two distinct categories - the dedicated type, which uses fixed input/output locations, and the more recent programmable type, which can simulate any chosen keys when the joystick is moved. Andrew Pennell, is concerned with the second variety - devices which should, in theory, offer compatibility with all software. He examines products from AGF Hardware, Cambridge Computing, Downsway and Stonechip.

All four of the interfaces looked at allow one joystick (or two in the case of AGF) to be connected to the Spectrum, via the industry standard 9-pin, D-type connector. Any joystick used must be the switched type, and not the proportional variety as used on the BBC Micro, for example. These consist of one switch for each of the four directions, and one for the fire button. Diagonal movement is recognised by two direction switches being activated simultaneously.

AGF HARDWARE SOLUTION

AGF was the first company to produce a programmable joystick, and this device remains the only true hardware-programmable interface. It consists of a large, exposed PCB with four ICs and 13 vertical bars. The back of the PCB is covered with black plastic, and for that reason it looks much neater from behind! To program it, two crocodile clips for each direction must be connected to the appropriate bars. A self-adhesive conversion table is supplied to convert each key into the two required connections. A total of ten crocodile clips must be attached, and probably it's best to do this with the power removed. Ten 'programming cards' are included on to which can be recorded the plugging arrangements for your most popular games.

When first connected, the interface firmly refused to respond to the fire button on the joystick, no matter how it was programmed. A dismantling of the stick showed nothing wrong, but closer inspection of the interface revealed a truly terrible joint to one of the clips. Swift action with the soldering iron soon had it working. One would hope that the interfaces are tested before dispatch to customers. This exercise brought to light another unredeeming feature of the unit - the edge connector that plugs into the Spectrum is incredibly tight, and almost impossible to remove (faced with the same problem, our editor had to resort to deft use of his letter opener). It's hard to imagine any of this palaver being good for the Spectrum's connector, although removal should not be necessary very often as a carry-through connector is provided to allow any further accessories to be plugged in, piggyback style.

AGF actually provides two joystick sockets, but these are connected to each other. The company says that this makes it easier to take part in two-player games, but some may think it's just as easy to pass on a single joystick to the co-player. The sockets are mounted on the top of the unit and therefore the joystick's plug and cable stick straight up in the air - thus easily obscuring one's view of the television screen.

However, once the operation had been figured out and the fault corrected, the interface worked very well. Programming is pretty simple and quick, and is of course retained once power is down. A simple demonstration cassette is included but, even so, at £33.95 it does seem a little on the expensive side.

CAMBRIDGE INCOMPATIBILITY

The next interface in line was the one from Cambridge Computing, and this comes supplied complete with joystick. It's controlled by software, but requires a program to be loaded from tape first. In fact the program allows a library of data for each game to be stored on the reverse side, so each key pattern has only to be entered once. This does mean though that the tape must be run before play can begin. During the first programming sequence a problem soon became apparent - the whole machine 'hung' with the word 'OK' on the screen. It wouldn't even Break, so all that was left was to pull the plug out. Only after running through this loop again did the truth strike - your reviewer is one of the few to possess both a ZX Interface 1 and a Microdrive, and the Cambridge port uses one of the Microdrive I/O locations. Cambridge really has no excuse for this blunder, the Microdrive ports having been documented since the day the Spectrum was launched - take a look at page 160 of the manual, guys!

Interface 1 was removed for the rest of the test and that obviously means that the Cambridge interface will not work with any games that load from Microdrive. Once programmed, however, the joystick interface worked well, with either a normal stick connected, or with Cambridge's own. The latter has a second and independent fire button, which can be programmed to simulate a different key to the first. However, the only game to come to mind that needs two fire buttons is Penetrator.

To test the device thoroughly it was used on one of the toughest games for any joystick - Jetpac by Ultimate (your reviewer's normal rig being the Kempston non-programmable interface plus Competition-Pro joystick). Opinions on joysticks are very personal things, and one man's loathing is another man's love. However (to digress a little from interfaces) after playing with the Cambridge stick for some time it seemed to me the device somehow failed to make the grade. It's noisy and not very sensitive and the two fire buttons are quite small (in fact it seemed best to program them both to the same key). The shape of the case looks as if it is designed to be held in one hand and operated with the other, but cramp set in after a while and the only resort seemed to be to rest it on a table instead.

The Cambridge interface does have a carry-through edge connector, but if it is incompatible with the Microdrive it is possibly incompatible with most other add-ons too. That aside, it works well, the only hangup being the tape that needs to be loaded before use. It comes reasonably priced at £24.00 for the interface only, or £29.90 if the joystick is bought as well.

DOWNSWAY - IN REAL TIME

The Downs way unit is programmed in a very different way to the previous two - namely in 'real time'. There is a 2-way switch on the back of the unit, which is normally in the 'up' position for program mode. To program it, the memory in the interface must first be cleared - which is achieved quite simply by moving the stick to all its positions in turn, and pressing fire each time. This done, each of the eight positions may be programmed by the holding down of the relevant keys and the moving of the joystick to the required positions, each time letting it return to the centre position. The instructions say that the diagonals should be programmed first, but it seemed to me that any order would do, provided the fire button is left until last. A total of nine positions are required, and the diagonals in particular can demand a lot of finger dexterity as you press two keys with one hand and hold the stick exactly diagonal with the other.

Once programmed and switched back into the play mode, you're ready to start. However, one great advantage with the device is that the interface can continue to be programmed after a game has been loaded, and therefore any mistakes can be corrected as you go along.

The Downsway interface is easy to use, quick to program and also the cheapest, at £22.95. My only quibble is that there should be an indicator label near the programming switch.

STONECHIP DEXTERITY

The final interface to come under scrutiny, by Stonechip, at first glance seems very similar to the Downsway one. It's programmed in the same way, the only apparent difference being that there is a 3-way switch - selecting normal, program or play modes. However, in use it proved to be rather different to the Downsway device. When in program mode, the Spectrum behaves strangely. It makes unusual buzzing sounds, and the border flashes. But the sequence of operations to program it remains the same, although with the one important difference - twice as many operations are required, as the joystick has to have all eight positions programmed once with the fire button pressed and again with it released. As well as taking some time, the task proved not an easy one. To program each diagonal with fire held down requires three keys to be pressed with one hand while the other holds the stick diagonal and presses the fire button. And now, with my teeth...

As with the Downsway unit it can be re-programmed after a game has been loaded, to correct any errors - a useful facility. Once all is ready the unit must be switched to the play mode for the joystick to be able simulate the keys. But this in itself presents problems for now you will notice that no keys on the keyboard work, and the ear socket is disabled. That means programs will not load and the switch has to be continually flicked back in order to re- enable the keyboard and thus allow the choosing of options from menus.

The Stonechip interface seems to offer similar facilities to the Downsway one, but with several disadvantages to weigh against it. It's also more expensive, at £24.95.

MODUS OPERANDI

How do they all work? Well, the Spectrum keyboard is based on an eight by five matrix, and was designed to be as simple as possible to read electronically. The AGF interface duplicates the matrix, but instead of having keys on it you can connect each directional switch at a particular point to simulate any key. This is electronically quite easy, but difficult to manufacture because of the matrix connections. The other interfaces are all basically similar to one another, showing just minor differences. They each contain 1K of RAM, not (as normal) in the memory map but in fact in the keyboard I/O space. This enables them to be programmed, ie. have the RAM written to, and then simulate the keys when they are read.

The actual method of switching between modes differs widely between the three. Cambridge uses another I/O port as a switch whereas the others just use a switch. The Stonechip design only has three ICs, excluding the RAM chips, but one can't help feeling that too many features have been cut to reduce the chip count.

TAKE YOUR PICK

In conclusion, it's worth the potential purchaser first deciding whether a cheaper, dedicated interface will suffice. There are three main types, produced by Kempston, Sinclair and AGF. If it will not, then choose the method you wish to use to program it - hardware, software or real-time. My personal view is that the Downsway unit takes the chequered flag, being cheapest and most easy to use.

However, the AGF interface may be worth the extra expense for those preferring something that's hardware programmed - even if, as in this case, the result is a little unsightly.

REC. PRICE: £24.00 (£29.90 with joystick)

PROGRAMMED BY: Software

COMMENTS: Cannot be used with Microdrive connected, must load tape before use, reasonably priced, works well.