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Using inc rotary encoder as a spinner - need help understanding counts
TheManuel:
By the way, would there be any advantage in getting getting the 360p/r variant instead?
They cost the same and I thought better resolution would be better but I ask in case I’m missing anything.
PL1:
--- Quote from: TheManuel on February 19, 2025, 09:00:55 pm ---By the way, would there be any advantage in getting getting the 360p/r variant instead?
--- End quote ---
Either version should be fine for most games, but low resolution game spinners like Kick (12 count) could be harder to fine tune with the 600p/r version because sensitivity is set in 1% increments in the MAME menu.
The math is a little easier with the 600p/r version -- settings are 1/2 of the commonly available TT2/SpinTrak sensitivity settings.
https://forum.arcadecontrols.com/index.php/topic,164017.0.html
https://wiki.arcadecontrols.com/index.php/Spinner_Turn_Count
Sensitivity = 100 * (Counts_Per_Revolution for game) / (transitions per rotation of your spinner)
- 600p/r sensitivity for Kick = 100 * 12 / 2400 = 0.5%
- 360p/r sensitivity for Kick = 100 * 12 / 1440 = 0.83%
Scott
EDIT: Looking closer at the possible range of sensitivity values, the 360p/r is the better choice of the two.
It will handle the highest value game, Arkanoid - Revenge of Doh (972 count), with about a 68% sensitivity setting (100 * 972 / 1440 = 67.5%) and give you more fine adjustability for the lower value games.
If you can find one, a 240p/r encoder would be even closer to an exact match (100 * 972 / 960 = 101.25%) -- you probably wouldn't want to go lower than that.
TheManuel:
Man, I did not even think about that. Really good point!
I think you meant to say "...could be harder to fine tune with the 360p/r version...", based on the rest of the message.
I'll be ordering that 600p/r encoder now. I'm looking forward to making Arkanoid more playable. It's nearly impossible with my current one.
Thank you for your help on this and everything else.
PL1:
--- Quote from: TheManuel on February 19, 2025, 10:25:16 pm ---I think you meant to say "...could be harder to fine tune with the 360p/r version...", based on the rest of the message.
--- End quote ---
No, I meant what I said.
The ideal setting for Kick with a 600p/r encoder would be 0.5%.
- Since the lowest possible setting is 1%, Kick will be at 200% of the ideal sensitivity.
The ideal setting for Kick with a 360p/r encoder would be 0.83%.
- Since the lowest possible setting is 1%, Kick will be at 120% of the ideal sensitivity.
The ideal setting for Kick with a 300p/r encoder would be 1%.
- Since the lowest possible setting is 1%, Kick can be set exactly to the ideal sensitivity.
You can only adjust MAME sensitivity in 1% increments.
- 1% of 2400 (600p/r encoder) = 24 steps. Bigger # of steps per 1% increment = less able to fine tune.
- 1% of 1440 (360p/r encoder) = 14.4 steps.
- 1% of 1200 (300p/r TT2/SpinTrak) = 12 steps. Smaller # of steps per 1% increment = more able to fine tune.
Have you ever heard anyone complain that their TT2/SpinTrak (300p/r) can't handle Arkanoid? I haven't because 300p/r is high enough resolution to handle it just fine.
The higher resolution of that 600p/r encoder is largely wasted because you have to turn the sensitivity way down in MAME.
A 600p/r encoder has so many transitions that the highest count game, Arkanoid - Revenge of Doh (972 count), will only have a sensitivity setting of about 41 percent. (100 * 972 / 2400 = 40.5%)
- The 360p/r is a better choice with about a 68% MAME sensitivity setting. (100 * 972 / 1440 = 67.5%)
- A 300p/r encoder would be even better than that. (100 * 972 / 1200 = 81%)
- A 240p/r encoder (if you can find one) would be about as low as you would want to go. (100 * 972 / 960 = 101.25%)
Scott
TheManuel:
Duh!!! What a thick head I have.
Thank you for clarifying all that.
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