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Optical Control Resolution - Info Needed

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Derrick Renaud:
I want to start keeping track of the resolution of the actual controls used for games.  This will (hopefully) be included in MAME.  This info will help to better document the controls, and possibly lead to auto-sensitivity adjustment based on the control used for MAME.

I need factual info of the number of optical counts for a full turn of the control.  Usually 360 degrees.  If it is less, eg 270, then I need to know that also.  No guesses please.

For example,
Tempest, 360 Spinner, 72 count

To show how the auto setting would work, if you tell MAME the control you use has 1200 counts per turn, MAME will do:
Sensitivity = 100 * 72 / 1200 = 6%

This will now make your control turn the exact amount of the original control.  I do not care about knob size or anything.  It does not effect the number of counts per turn.  It just makes it feel different in your hand.

thanks,
D.

u_rebelscum:
Reminder to all posters, Derrick wants the count per full turn, which can 1x, 2x, or 4x the number of teeth per full turn.

The one I know OTTOMH is 720 degrees (not that this info is needed for the current faked inputs):

720 (skate or die), 360 spinner "joystick", 144 count (72 teeth)


And there was that post a little back about arkanoid and arkanoid 2 (revenge of doh) using the same hardware, but the second having twice the count as the first.

crashwg:
I'm not sure I follow exactly what you're doing math for...

I just counted the teeth on my D.O.T. spinner though and there are 128!  :o

Kremmit:
I can't get you the actual count per revolution that Robin is talking about, as that requires knowing what the game logic does with the simple optic count from the controller, but I can get you some accurate encoder wheel tooth counts.  I'll leave the game logic end to the MAMEDev types.   ;)

From an old post of mine:  (http://forum.arcadecontrols.com/index.php?topic=50641.msg494624#msg494624) 

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I've played around with lots of different encoder wheels, with different tooth counts.  Just for reference, here are the ones I actually saved the numbers for:

DOT spinner (original) has 128 teeth.
The Oscar DOT has 72, same as Blasteroids, Tempest, Oscar Vortex, and the 720 joystick.
The Pole Position wheel has 24 teeth, with the gearing you get just shy of 4 revolutions of the encoder per turn of the wheel, for somewhere around 80 teeth actually passing through the optics per one turn of the steering wheel.

Arkanoid is the special one.  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.

So, shaft 2 spins 4.5 times for every turn of shaft 1.  Shaft 3 spins 4.5 turns for every turn of shaft 2.  4.5 squared is 20.25 turns of the encoder for every turn of the knob, which is 486 teeth per revolution of the spinner knob!!

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Off the top of my head, I know that the Roadblasters wheel uses the same 24 teeth as the Pole wheel, but I don't know how many actually pass the optics with a full left/right turn, since it's a limited wheel.  Major Havoc roller uses the same 24 tooth wheel again, but with the big green roller turning the smaller metal roller that spins the encoder wheel, you'd need exact diameters of those parts to calculate the turn ratio.  Happ and Betson trackballs also use a 24-tooth wheel on each axis, but the same ball-to-roller turn ratio comes up again.   The Forgotten Worlds spinner looks identical to the Arkanoid one, but I haven't counted the teeth to verify. 

Sometime after Christmas I'll dig through the parts closet and get you the exact gearing on the Pole wheel, see how many of those others I can clear up, and get counts for few other goodies.

Derrick Renaud:

--- Quote from: u_rebelscum on December 22, 2006, 07:01:34 pm ---Reminder to all posters, Derrick wants the count per full turn, which can 1x, 2x, or 4x the number of teeth per full turn.

--- End quote ---

Robin is right, I do need to know this.  But the easiest way if you can not precisely do that is:

Count the actual teeth that pass in 1 full turn.  Just tell me if that is full 360 or if that is a limited steering wheel type.  Then just tell me the degrees that the control can turn.

Also tell me how far the player moves across the screen in 1 full turn.  This may not apply for racing games.  It is for arkanoid type games where the player moves a set amount per turn.  Or for a cameltry type game, how many rotations on screen per 1 rotation of the control.  From that I can guess if the control reads 1x, 2x, 4x.

Thanks,
D.

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