Spinner Turn Count

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This is intended to be a page to keep track of the correct turns ratio of spinner/dial/paddle/trackball-controlled arcade games. Below is comma-separated text, hopefully this is a useful format.

Q: How do I use this information?

A: To tweak the analog sensitivity in MAME to better emulate real hardware.

An example from the first link below: Tempest, 72 count

if the control you use has 1200 counts per turn, the sensitivity calculation is: Sensitivity = 100 * 72 / 1200 = 6%

Links (Recommended Reading)






Effective_Tooth_Count = teeth that pass through the optical sensor per revolution of the knob (multiply by any gear ratios to obtain)

Counts_Per_Revolution = could be 1x, 2x, or 4x of the Effective_Tooth_Count (depends on original hardware interpretation of optical sensor information)

Other_Notes = quantitative information relating to game play (like degrees of turn from one side of the screen to another - useful for potentiometer games like Warlords)

Game Effective_Tooth_Count Counts_Per_Revolution Other_Notes
720 degrees 72 144 LETA 2x (schematic)
Arkanoid 486 486 Geared: The knob attaches to shaft #1, which has a 72 tooth gear on it. That gear turns a 16 tooth gear on shaft #2. Shaft #2 also has a 72 tooth gear on it, which then turns a 16 tooth gear on shaft #3. Shaft #3 also has the encoder wheel on it, which has 24 teeth. 120-130 deg = one traversal across the screen
Aztarac 4x Same spinner as Mad Planets
Blasteroids 72 288 LETA 4x (schematic)
Crater Raider 64 64
Caliber .50 24 Loop24 optical rotary stick
Cameltry 486 Same Spinner as Arkanoid
Dark Planet 64 64 6-bit rotary encoder
Demolition Derby (2-Player Mono Board Version) 8
Disks of Tron 128 128
Forgotten Worlds geared spinner
Ivan Ironman Offroad a) 154.286 or
b) 164.57
a) 60 teeth on the steering wheel shaft, meshes with a 14 tooth gear on the encoder shaft, which has 36 teeth on its encoder wheel
b) 96 teeth on steering wheel shaft, to 14 tooth gear on encoder shaft, which has 24 teeth on encoder wheel.
Kick / Kickman 12 Ball-shaped roller.
Off the Wall 128 256 LETA 2x (schematic)
Omega Race 64 64 Omega Race uses a 6-bit (64-position) rotary encoder
Pole Position
Pole Position II
102 6/7 102 6/7 Geared: 60 tooth gear on wheel shaft, 14 tooth gear on 24 tooth encoder disk shaft => (60 / 14) * 24 = 102 6/7
Revenge of DOH 486 972 Same spinner as Arkanoid
RoadBlasters 154 2/7 Wheel/Yoke: 60 tooth gear turns 14 tooth gear with 36 tooth encoder disc. Limited angle of rotation.
Super Speed Race 64 64 6-bit rotary encoder
Tempest 72 72 1 full turn moves 5 spaces on first screen
Tron 128 128
Two Tigers (conversion) 64 64
Star Trek
64 64 All use the same spinner
Turbo 2 1/2 turns to go across the screen
Mad Planets 1x
Monte Carlo
Super Sprint
Drag Race
Fire Truck
Sprint 36 36
Championship Sprint
36 72

Trackball Hardware

Trackball resolution Notes
Happ 2.25 inch trackball 149.2 (no wear) 2.25 inch ball, 0.362 inch roller, 24 tooth encoder disc
Happ 3 inch trackball 167.4 (no wear) 3 inch ball, 0.43 inch roller, 24 tooth encoder disc
Atari 4.5 inch trackball 330.6 (no wear) 4.5 inch ball, 0.49 inch roller, 36 tooth encoder wheel

Trackball Games

Game Trackball Multiplier Notes
Crystal Castles Atari/Happ 3 in 2x
Marble Madness Atari/Happ 3 in 4x
Rampart Atari/Happ 3 in 2x
Snake Pit Wico 2.25 in
Cabal Wico 2.25 in

Pot Based

Game Gear Ratio Other_Notes
Warlords 1 120-130 deg one traversal end to end of castle
Final Lap 2/3
Moto Frenzy 1
Breakout 1
Super Breakout 1 120-130 deg one traversal across the screen
Star Wars 15/7 (left/right) 30/7 (up/down) Yoke
Paperboy 30/7 (left/right) 30/7 (up/down) Yoke

Trackball Games: Game Name, Notes

Crystal Castles, 1st screen BB moves length of line above his head from center of trackball moved to one side

Centipede, 1 trackball move 1 end to other (stock tb) 2 1/2 mushroom lengths

Missile Command 1 full end to end visible trackball movement goes from left to the right of the little bump after the missile base

Atari LETA Chip: several of Atari's optical-control games used the LETA quadrature-decoder chip. It could be set to a 2x or 4x resolution. Therefore all of the below games are either 2x or 4x.
Major Havoc
Marble Madness
Crystal Castles
Off The Wall
Championship Sprint
Super Sprint