Atari Steering Wheel - How many teeth for an encoder wheel?

[leapinlew]

So... I'm going to try and print some encoder wheels on transparencies to mount on the end of the steering wheel.

My question is, how many teeth and what size? I'd like a 2-3" wheel and not sure how many teeth to put on it to get the optimal feel in mame for driving games. I realize I'll have to tweak each game, but I want to start with a good encoder wheel to begin with. I printed a 3" wheel with 300 teeth and it looks pretty good, just curious if anyone else who has experience with this has any thoughts.

Also, whats a tool that looks like a compass, but has a razor blade on it so I can cut these encoder wheels?

Thanks!

[RayB]

Also, whats a tool that looks like a compass, but has a razor blade on it so I can cut these encoder wheels?

Actually they sell little blades that fit into designer compasses, where the lead would normally go. Or also there are attachments meant for holding a marker or other drawing tool to a compass. You could use an exacto knife with one of those.

If i were you I'd ask on the BST forum if anyone can spare a wheel. They don't cost much and can be mailed in an envelope.

[leapinlew]

Also, whats a tool that looks like a compass, but has a razor blade on it so I can cut these encoder wheels?

If i were you I'd ask on the BST forum if anyone can spare a wheel. They don't cost much and can be mailed in an envelope.

Well damn Ray, I wish you worked at the Office Depot where I just bought the transparencies!

[Kremmit]

The odds of anybody working at an Office Depot knowing anything about actual office supplies is nil.  They only get trained on registers and extended warranties.

[leapinlew]

Ok. I printed a couple wheels - 2.5 inches. 1 with 300 teeth and 1 with 600 teeth. I don't know what the difference is cause neither is working. I've attached a couple pictures so hopefully someone can point me in some sort of direction.

I tried the mice before taking them apart to ensure they worked. They did. I partially put things together for a mock fit before I finished making the mouse PCB cage. I printed this on a laser printer. Is the toner not dense enough to block the optical sensor?

Any help would be greatly appreciated...

[leapinlew]

Just read up on the hillbilly spinner... gonna try 30 teeth now too

[leapinlew]

Success! appears that I needed to move the plastic encoder wheel through some slots on the pcb. I've remounted it with 3/4" ply instead of the 1/4 and it's much more sturdy.

Anyone have any idea what the optimal amount of teeth are?

[leapinlew]

Teeth tried:

15 - really choppy
30 - choppy
60 - half as choppy as the 30, but since the 30 was sucky choppy. It still sucks.
300 - smooth like using a mouse
600 - didn't even register

There is probably a good number in 250 or so, but 300 feels real good. Going to go with it. I assume I'll have to adjust the mouse settings for each game anyhow.

[Kremmit]

Nice!  300 is higher than anything I've ever seen, except the Arkanoid spinner.  You'll be setting your analog sensetivity well below 100 on most, if not all, games.  Have you tried spinning it really, really fast, to see if any backspin rears it's ugly head?

Was the 15-tooth version the original LeMans wheel?

[leapinlew]

There were 36 on the lemans...

I would've used it and tried to increase the resolution in the game, but it was hard to get the mouse pcb to fit.

[u_rebelscum]

Anyone have any idea what the optimal amount of teeth are?

If there was a single number of teeth that would work perfect for everything, it would have been found and posted all over this site.

Reasons why there is no one perfect number:

• Differences in number in original hardward,
• Gearing (if any) in original hardward,
• Differences in number of polling per tooth (1, 2 or 4) in original hardware (all current PC hardware do 4 per AFAIK),
• The sensitivity, accuracy, and max speed of the PC mouse hardware,
• Differences in mame's driver analog default sensitivity setting (which is usually set by author's mouse sensitive, aka number teeth),
• Differences in windows drivers and driver settings,
• Differences in PC's number of teeth per rotation, and
• Differences in distance between hacked sensors.

That last one is "minor", but can cause situations such as 300 teeth are perfect for person A but not work for person B, while 303 perfect for person B while work okay except cause problems at high speeds for person A.

The second to last actually isn't exactly related, but causes the similar problem of no single value for mame's analog sensitivity.

The two before that theoretically should help by adding a range of number of teeth, but in practice just confuse the issue, make it harder to compare tests from different people, and cause other problems with normal hardware.

All in all, the current "best practice" falls in one of two schools.
A) Get the original numbers for a specific game and try to copy them.  This depends on which game is modeled, and isn't perfect for other games, of course.
B) Try to get the highest number of teeth possible before reaching the limits of the PC sensors hardware & driver.  This depends on the hardware being hacked and if it's straight shaft, geared, or ball-to-roller (TB).  Then adjust mame's analog sensitivity for each game to try to match the original feel.


From the sound of it, you're going school B), and your sensor minimun width limit falls between 300 & 600 teeth (unless 600 teeth is under your printers effective minimun size limit).  If 300 works at high speed, I suggest just sticking with it and adjusting mame's analog sensitivity.

My 2 cents.

[leapinlew]

Thanks - I am sticking with 300....

I was primarily asking how many teeth because of a couple reasons.

1. I didn't know if it was a number like 58 or a number like 1,500. I didn't want to reinvent the wheel here - pun intended
2. I don't know what the hell I'm doing. I did some trial and error and got decent results.

I'll adjust the settings in mame. I'm hoping it'll be ok.

[u_rebelscum]

Thanks - I am sticking with 300....

I was primarily asking how many teeth because of a couple reasons.

1. I didn't know if it was a number like 58 or a number like 1,500. I didn't want to reinvent the wheel here - pun intended
2. I don't know what the hell I'm doing....

Yes, very understandable.  Usually the question is asked in the opposite direction:
"What is the perfect mame analog sensitivity setting (for all game's with xyz device)?", which is why you probably didn't find an answer in the search.

I did some trial and error and got decent results.

The theory I wrote is nice, but trial & error works wonders.  However as you said, why reinvent the wheel if not needed.  

I'll adjust the settings in mame. I'm hoping it'll be ok.

Could you let us know how things go after you try it for a while on a few games?  It would be great to hear how well it works out in the long run.

Good luck!