The device that "joystick killer" games just can't kill...
To prevent confusion, in the arcade world, the name rotary joystick means something different then shown on this page. I wasn't aware of this until it was already much too late, a short while after I had finished my project and published the video. If I knew this all before I most certainly would have chosen a less confusing name. I'm sorry if this causes disappointment to people who are looking for a real arcade rotary joystick. But, when I started this project, I assumed that the name rotary would be great for a project with something that you could actually rotate, which my "joystick" does. Although, I have to admit, that my "joystick" isn't a joystick, but it does act like one electrically. Or to be more precise, it can generate the same signals a real joystick can. So to make a long story short, it's just a controller that requires you to rotate a large disc instead of wiggling a stick. And that's realy all there is to it.
Why this project?
Joysticks are wonderful devices. A plastic case that could be hold in your hand and holds only five switches, four for each direction and one fire button. For many years this proven to be the best way to play an 8-bit game. From Pacman to international karate, the joystick was king. And although some games could be intense, most joystick could stand the pressure. But in the golden days of the 8-bit games for the C64 (and very likely other platforms as well) there were a few games are a little more demanding regarding joystick usage. No gentle movements, nope just wiggle your joystick as fast as you can to the left and right. Do this until you win (which in some games is impossible) or until something breaks, which in many cases was the joystick.
There are different kind of joysticks mostly to be divided into two groups. High end arcade quality... and cheap rubbish. The cheap rubbish was simply not suited for use with the games mentioned on this page. Games that required you to move your joystick as fast as you can in all (or some) levels of the game. A short list of such games: Activision Decathlon, Daley Thompson's Decathlon, Daley Thompson's Olympic Challenge, Track & Field, Combat School, Space Academy, Winter Olympiad 88, WWF Wrestlemania.
The games above, fit into the category "joystick killing" games, simply because they have the potential to dramatically reduce the lifespan of your joystick. Now the listed games are for the C64, butI'm sure that there are games for other 8-bit platforms that work in the same way and that also use the 9-pole sub-D connector for their joysticks. For example the Atari and Amiga systems, because this rotary joystick design using nothing but switches, you can connect it safely to any platform that supports the Atari 9-pole joystick plug.
Building a joystick just for "joystick killer" games
I made a small video to show off my "rotary joystick" project.The video shows three joystick and they all fail during the game. The failures shown were actually very common failures, although not everyone has experienced them personally. When I was a youngster and played decathlon for the first time, I simply did not have the strength to pull the stick from its base. But now 30 years later, it took no effort at all. The detail that I couldn't even afford such a joystick is a completely different story. But to make a long story short... these kind of defects could happen to anybody at any time, but are more likely to be encountered during or shortly after a game of the that has "joystick killer" potential.
In order to make a joystick that can withstand the repetitive motion of wiggling the stick left and right for a long period of time we must be aware of how the game works. Which isn't all to difficult. The game requires the signals of the lines left/right to be pulled down in an alternating fashion, however most games do not care if you also activate up and down when moving from left to right (or vice versa). So a simple wheel that rotates and activates the switches is all we need. Then turning the wheel in the desired speed results in the desired movement of the game character. In other words, the faster you spin the sooner you'll win.
But to keep the wheel from wear and tear due to mechanical contact switches needed to be activated, some special switches need to be used. Reed switches or reed contacts. These can be operated by moving a small magnet over the contacts. By attaching the magnet to the rotating wheel the wheel can spin freely while activating the switches when passing over them. Allowing you to spin the wheel very fast with little effort... well "little" when comparing it to the joystick wiggle movement you would otherwise need to do in order to achieve the same effect in the game.
Now you could say that this design could be done electronically, as it could have been done with an Arduino, a 555, although a simple two transistor astable multivibrator design is really all you need (which as a youngster I already did, I modified my super-cheap "joystick turbo junior" with a two transistor circuit), it worked perfectly but somehow the game element is completely lost with this kind of electronic sollution. And why don't make it even easier, no electronics at all. So in other words, this design is as easy as it gets. Four magnetic contacts and one simple switch and the rest is glue and plastic. So no real electronic skills (other then soldering wires) needed.
But the rotating wheel has one more benefit, as it allows you to still play the game (electronically, would be cheating) because you still need to put some effort into the movement of the character on your screen. And it allows you to play the game "Crank Crank Revolution" which is a wonderful game made in 2018 and requires you to rotate your joystick (feel like grinding coffee beans the old way). And the rotary joystick is perfect for this game, it almost feels as if you are the musician yourself. So a big thanks to the maker(s) of this game as it is really fun and unique in so many ways.
Build a rotary joystick
Thanks to the power of 3D printing technology, now anybody can make this device. Although it requires some patience because it does take a few hours to print the top and bottom halve of the joystick case. Which was designed to be very rigid/solid. And the rotating wheel is to be printed with a high infill to give it some mass. Though you could make it heavier by adding some metal, but that's not really required and would only complicate the build. In other words, it is a simple build. four parts, top, bottom, rotating wheel, fire button. An old RS-232 serial cable (or joystick extension cable) and a decent amount of hot-glue. Ohh... and four reed contacts (size: 2x14 mm) a arcade style micro-switch and a neodymium magnet (size: 2x6mm or somthing of that size, but not much bigger). In other words, some relatively easy available components.
The building instructions are nothing more then "watch the YouTube video", as there isn't very much more to say about it here. Though there is one tip I would like to share: when putting it all together, you may need to play a bit with the location of the magnet, the rotating wheel has a very deep hole to insert the magnet into, so you mat need to push it further inward if the magnet is too strong.
Regarding the 3D printing, I printed all the parts with black ABS but I should have printed the rotating wheel and fire button in red, as that would have made it look so much better. Mostly because the joysticks of that time used that color scheme a lot. The main reason for me was that I didn't have a spool of red and didn't want to buy one knowing that I would not be using it for anything else I could have painted it red, but painting it isn't really an option I think. Because I'm afraid that the paint will be damaged eventually or come of completely and that would make it really look bad.