ADS Joystick for Spectrum ZX

ADS Joystick for Spectrum ZX

Year of manufacture: ~1984 Place of manufacture: Yugoslavia (Socialist Republic of Slovenia) Price: ~9000 DIN ~70$/€ in 2018 Produced by: ADS (Andrej Vihtelič, Gorazd Marinček, one unknown)

Spectrum ZX 48K and ADS joystick

I was casually browsing trough a local flea market, when a well-known rainbow cable caught my eye. Since it was attached to a joystick I didn’t recognize, the intrigue deepened, so I decided to buy it. Then the thrilling hunt for the origin of this piece of history started. A quick Google search produced two results (link1 and link2). Since this was made somewhere in Yugoslavia, things just got a lot more personal and interesting. But the sources for this period are scarce, so this one proved to be a challenging one. I decided to dig into the internet archives of an ancient local computer magazine called Moj Mikro. After some browsing I got lucky:

Moj Mikro #1 (January 1985, page 54)

ADS joystick is the creation of Slovenian computer enthusiasts. The joystick handle is made out of ski pole handles. This was an interesting solution primarily connected to the price since the cost would be much higher if they needed a new molding tool. A button is located at the top of the handle that is usually intended for shooting and it is well built. The base is simple, made out of plastic and large enough to ensure stability. It also includes suction caps to stick the joystick to the table. Further on there are two keys on the base, which can come in handy when writing programs, but have no use in standard settings. The production of the stick itself is solid, but is not considered higher than craft production. If the production of the joystick is solid enough for widespread use that cannot be said about the interface that only allows connection to the ZX spectrum. The switch is programmable, suitable for all possible connection modes. The design and the idea are inspired by the AGF interfaces. The connection methods can be changed by switching the ROM card. According to the manufacturers, the cards would be accessible for all of the most common connection modes. Another disadvantage is the automatic shooting system, which is always on full automatic, if you want it like that or not. The purpose for this was to simplify the game-play. You can shoot in burst mode by holding the key, but things get tricky if you play a game where the number of shots is limited.

Commercial for ADS joystick in Moj Micro #2 1985

However the most informative piece was a video about the history of computer engineering in Slovenia, suggested by a member of a Facebook group “Slovenski developerji”.

Interview with the Joystick creators starts at 39:36 (the video is in Slovenian)

The joystick was made by 3 students of Electrical Engineering and Faculty of Civil and Geodetic Engineering from Ljubljana University as a part time project.

Andrej Vihtelič

Gorazd Marinček

The third member unfortunately remains unknown. They were even on the news back in the day:

Original packaging of the product shown on the news.

And they were also contacted by a local factory which wanted to adopt their design to control industrial machines.

Since Spectrum joystick interfaces were always a mess (multiple inconsistent standards), the producers made "ROM" cards for enabling different connection modes. And I’m using a “ROM” term here loosely, it’s just a hardwired 5V to the appropriate pins, switching modes of operation.

Dissasembly:

Joystick was made of two units, the actual controller and a plugable/programmable part, with the rom card on top.

The design overall was quite simple as the whole production was more on home made side than an actual industrial manufacture (as most of the computer industry in the Yugoslavia). Buttons for example are just two metal plates, that make contact (homemade leaf contact).

The home made leaf switches were the the source of many frustrations.

Although simple ADS Joystick still featured an autofire circuit.

The “mode” selection circuit that enabled to switch the joystick mode. It consist from 3 HEF4075BP (OR gate logic chips) and one unidentified as of yet (i need to disassemble it again sometime).

Although simple in design ADS Joystick still features some ingenious solutions, and is a testament to resourcefulness of early computer engineers. This find is a nice piece of Slovenian technical heritage and a tribute to the enthusiasm of Yugoslav engineers.