There is a popular set of arcade style joysticks made by a company called X-Arcade. A friend of mine owns one, and he was kind enough to send me a few links with information about these joysticks, and I thought I would share them here.
First, there is an online (Java-based) test program that shows the Tankstick buttons working:
And this page shows what the various buttons map to:
http://www.xgaming.com/service/images/Layouts/PC-MAC.htm
Of particular interest to me is the realization that Tankstick doesn’t appear as a USB joystick at all. Instead, it appears as a keyboard, and sends key presses for the joystick directions, buttons, etc. For models with a trackball (Tankstick+, for instance), I am guessing the trackball appears as a mouse. So, Tankstick is a keyboard/mouse, as opposed to an analog or (as I previously expected) digital joystick.
This means a third layer of support will be needed to create a conversion between Tankstick keyboard presses and the iCade sequences. This would be a very simple Arduino script since it removes any need for reading digital input pins or USB status bits. It does complicate things for me, however, since now I have to learn what it takes to expect data from either a keyboard or joystick (hopefully without requiring the user to switch). My ultimate goal is to have my code “just work” whether the user is wiring up their own controls to the digital inputs, or using a USB host shield and plugging up an analog or digital joystick, or keyboard device like the Tankstick.
Incidentally, the Tankstick still supports the “ancient” (by computer standards) PS/2 style keyboards as well, and those could be read on an Ardunio (or Teensy) using very little add-on hardware and digital pins. It seems a Tankstick-to-iCade converter could be done very easily, so maybe I can spin one of those off as well.
More updates when I have time to get back to this…