270/360 wheel?

[tony.silveira]

hi all,

i remember yeeeeeaaaars ago, actlabs had a product announcement they were working in; a steering wheel the could be switched from 360 free spinning to 270 fixed.

anyone ever here if something like this being worked on?  is it possible?

[RandyT]

It's certainly possible.  You just start with a free-spinning wheel, which will by default have some type of encoder.  Then just add physical and removable stops to limit how far it can be turned.  The only thing you might run into is the need to calibrate the wheel to those stops and possibly for the specific range of output you wish to get from the wheel if it's different from the amount of rotation.

A better approach might be to use an absolute positioning encoder, and make sure that the stops on the wheel shaft are positioned such that the center of range coincides with the zero-point of the encoder.  Then you wouldn't need to calibrate, so long as the physical limiters were always in the same place.  However, it could still screw up any game or software which assumes the current position of the wheel to be centered at start-up, so there's probably no way to really avoid the calibration stage.  Even expensive racing wheels need to do this, but they have FFB motors so it happens automatically. 

 

[Xiaou2]

It's certainly possible.  You just start with a free-spinning wheel, which will by default have some type of encoder.  Then just add physical and removable stops to limit how far it can be turned.  The only thing you might run into is the need to calibrate the wheel to those stops and possibly for the specific range of output you wish to get from the wheel if it's different from the amount of rotation.

A better approach might be to use an absolute positioning encoder, and make sure that the stops on the wheel shaft are positioned such that the center of range coincides with the zero-point of the encoder.  Then you wouldn't need to calibrate, so long as the physical limiters were always in the same place.  However, it could still screw up any game or software which assumes the current position of the wheel to be centered at start-up, so there's probably no way to really avoid the calibration stage.  Even expensive racing wheels need to do this, but they have FFB motors so it happens automatically.

 You shouldnt need a calibration system, if you use a Physical system that prevents it.

 Many a year ago, I made up a prototype sketch of what could be done.  Ill include it here.

 Because its hard to see, due to the poor drawings..  the Basic premise is that:

 1)  The main wheel is always a  360 degree wheel,  with an always-on  Optical encoder / encoder disc.
 2)  To activate the POT mode... you use a lever to pull the POT assembly forwards, which couples to the main drive shaft, Via "D" shaped shaft ends.
 3)  Once the shaft is coupled, the POT assembly, with its springs and bumper stops, is actively usable.

 Since the D-Shafts cant physically be Coupled any other way than a perfect match... there is no way for the system to lose
calibration.

 The Only issue might be the potential for the spring system, not completely returning to center (which is an issues that any Pot based wheel
assembly can occur).   This wont effect the coupling though, because you can turn the 360 wheel, to any degree, to get the initial coupling.


 This all said... I didnt design certain aspects fully.   For example... for higher resolution, the POT end probably needs Gearing.
Also, many 360 degree Optical wheels, use Gearing on their encoders as well... to provide a much higher pulse rate
per inch of travel. (higher resolution)


 EDIT:

 Now, one of the things that could be considered a Problem with this... is that many Pot based driving games, use Buttons that are
located on the steering wheel... like  Spy Hunter.

 For certain games, one could use buttons placed next to the wheel..  as well as a  Shifter Assembly.  In fact, the shifter itself,
could be made to have a few buttons on the handgrip (IE: Turbo-Boost, like Turbo Outrun).

 But Spy Hunter would be impossible, without changing the actual wheel, to a hand-grip version.  And that would also likely
require a 360 degree wiring coupler... or..  the use of a battery powered (Wireless) button system.

 Thinking about it more.. if it was wireless... one could possibly leave the 360 wheel on,  and just Snap on the wheel with the
buttons.  (Snapping it onto the wheels edges, and or, a center mount locking system (maybe just a strong magnet).

[tony.silveira]

so who’s gonna build it so i can buy one

[RandyT]

so who’s gonna build it so i can buy one

Probably no-one The best bet would be to use an optical encoder, go at the range limiting (and spring centering if desired) mechanically and let MAME do the rest.  If you look at how some have tackled DIY SW yokes, those same mechanical principles can work for centering. 

If I were to try doing something like this, I would consider using a "split-end" tube which was full-time spring-centered and rotation-limited, with the free-spinning 360degree shaft attached to the wheel and encoder, going down the center.  That way, you could turn a clamping screw to switch between modes.