Spinners and Dials

What is a Spinner?

You might remember the spinner from games like Tempest and Arkanoid. The player turns a knob to move the on-screen character. But what's going on behind the scenes; what's that knob attached to?

Underneath the control panel, the shaft comes down from the knob above. Mounted on the shaft, is an optical encoder wheel- a flat disk with notches cut around the outside edge. These notches pass though a set of infra-red optics, that detect the notches as they spin by. There are two sets of optics, spaced such that they see the notches spin by just a little bit out of sync. The combined signal from both of these optics tells the game which direction the disk is turning, and how fast. This is also how a trackball works, as well as a ball-type PC mouse.

Spinner Varieties

1. Tempest- Fast spinning lightweight spinner, which is very popular with arcade enthusiassts. It has 72 teeth on the encoder wheel, with nylon upper and lower bearings on the shaft. This was the model for the Oscar Vortex aftermarket spinner.
2. Arkanoid- The "geared" spinner. Rather than mounting the encoder wheel directly to the shaft, the Arkanoid spinner used two sets of gears between the knob and the encoder wheel, to make the spinner extremely sensitive. While the encoder wheel only has 24 notches, the gearing causes 486 notches to pass through the optics for every turn of the knob! Due to the lightweight and friction from the gearing, the Arkanoid spinner stops the instant you take your hand off the knob.
3. Discs of Tron Push/Pull- This spinner used a giant 128-notch encoder wheel with a push / pull switch feature built into the spindle shaft. When the player pulled up or down on the spinner, a leafswitch was activated. This was used to control the high / low aim of the disc in later levels of the game. Zwackery also used a Push/Pull spinner, and Forgotten Worlds used a push only (no pull) spinner. Oscar Controls marketed a Push/Pull spinner with a slightly different design, and a smaller 72 notch encoder wheel, but it is no longer available for purchase. The Oscar V2 had a Push option, and a Pull kit was rumored to be in the works before Oscar Controls closed down.

Spinner Brands

1. Oscar Controls- Was a manufacturere of spinners to the hobbyist market until recently. Several models were produced over the years, including the Model One, Pro, Vortex, Push/Pull, and V2.
2. SlikStik- Tornado is billed as the "longest spinning" spinner on the market, the Tornado is currently the spinner that's been on the market the longest. With an extra-small footprint, and dual-bearing design, the Tornado is very well made. Several knob options are also available. The Tornado comes with it's own USB or PS/2 interface. Plans to sell the Tornado with a plain-jane optic card have also been announced.
3. GroovyGameGear- The TurboTwist is new to the market. Like the SlikStik Tornado, the TurboTwist also has a small footprint and a dual-bearing design. The TurboTwist has an extra-high resolution encoder wheel, and comes with it's own USB or PS/2 Opti-Wiz interface. The interface can be configured to put the spinner on the X, Y, or Z mouse axis, and will control other optic devices on the remaining two axes, such as a trackball, or additional spinners/steering wheels/optical rotary joysticks. A plain-jane optic card version has also been announced.
4. ArcadeGames4U- The cyclone is also new to the market. It has a dual-bearing design, with a lower resolution encoder wheel. The Cyclone ships with an optic card, but no interface.
5. Build Your Own!- Many users have build their own spinners from whatever parts they had available- Hard drive bearings, skateboard bearings, whatever. Use your imagination, or use this guide created by Nathan Strum. Download the PDF guide here for building your own.

Two Spinners on a control panel; is it worth it?

The answer is an unequivocal maybe. There are several factors to keep in mind when trying to determine whether you should buy and install 2 spinners on your control panel.

1. Budget- Spinners are somewhat expensive. Buying 2 aftermarket spinners with optics will set you back about $80-$160.
2. Software- Can your software support 2 mice at the same time. Make sure you have a version of mame that can support 2 spinners if they're both individual USB units. If you have them both plugged into an Optipac this won't be a problem.
3. Space- Depending on the model, spinners can take up a lot of room under the surface of a control panel. The Oscar Controls Push/Pull spinner was approximately 5.5x6" for instance. Also, the more spinners you have, the less room you may have for other features and joysticks.
4. Games- Most importantly, do you like an games that use more than 1 spinner? Below is a (non-definitive) list of dual spinner games
   1. Blasteroids
   2. Warlords
   3. Super Off Road
   4. Super Sprint
   5. Bad Lands
   6. Off the Wall
   7. Sente's Off the Wall
   8. Atari 2 player games