Possible to build a Trackball out of Arcade parts for Atari 7800?

[Wyluli Wolf]

Would it be possible to take an arcade trackball such as THIS or THIS and wire it to work on the Atari 7800 and 2600? I'd like to have a button on either side of the ball as well.

 

If it is possible can anyone elaborate on how, specifically, to wire it up?

 

(Yes, I know about the cx-22 and cx-80 trackballs. I'm tinkering with the idea of a custom case etc.)

 

Thanks!

 

[+DrVenkman]

You can't use something like that out of the box and just "wire it up." You'd have to rig up the optical encoders to generate the same kind of output (similar but not the same as Grey Code) that a CX-22 produces in Trak-Ball mode.

 

And more to the point, you'll need more 7800 titles designed to use a Trak-Ball. There were no originals that did so, though there is a Centipede re-write available in the AA Store called Centipede-TB that does.

[Wyluli Wolf]

You can't use something like that out of the box and just "wire it up." You'd have to rig up the optical encoders to generate the same kind of output (similar but not the same as Grey Code) that a CX-22 produces in Trak-Ball mode.

 

And more to the point, you'll need more 7800 titles designed to use a Trak-Ball. There were no originals that did so, though there is a Centipede re-write available in the AA Store called Centipede-TB that does.

The 2600 had more games but I guess overall, it's not going to be worth the trouble. I'm not sure how to implement the grey code etc. Thank you for the reply! I figured that was the case but just wondered if it was possible.

[Andromeda Stardust]

You can't use something like that out of the box and just "wire it up." You'd have to rig up the optical encoders to generate the same kind of output (similar but not the same as Grey Code) that a CX-22 produces in Trak-Ball mode.

 

And more to the point, you'll need more 7800 titles designed to use a Trak-Ball. There were no originals that did so, though there is a Centipede re-write available in the AA Store called Centipede-TB that does.

This is true to an extent. There is no "CX-80" mode. All CX-80s function as CX-22 or very rarely factory modded units that function as ST-Mouse. ST-Mouse uses pure gray code. You still need logic buffers connected to the trackball outputs. ST-mode uses vertical A/B inputs on left/right joystick; horizontal A/B inputs on up/down joystick. CX-22 has half the precision of ST mouse because one side of the vertical and horizontal gray code gets replaced with a directional key. Joyleft and Joyup are keyed and determine the direction of the last increment. Joyright and Joydown oscillate back and forth when the trackball is in motion. Again the horizontal inputs on the joystick indicate vertical movement, and the vertical inputs on the joystick indicate horizontal movement.

 

Sorry I don't have a schematic handy. If you're going to get a trackball, I recommend a CX-80 for superior build quality. Also a small number of CX-22 trackballs do not have a JS/TB switch and are permanently wired for joystick mode. If you get a CX-22, make sure it has a switch. Also Wiko trackballs are joystick mode only but could be modded to output gray code.

 

It is also notable that the CX-80 and CX-22 have 2.25 inch diameter, so for a cheap cosmetic mod, you can drop in a Regulation American style billiard ball. I bought an 8-ball from PoolDawgs to customize my CX-80.

[Wyluli Wolf]

This is true to an extent. There is no "CX-80" mode. All CX-80s function as CX-22 or very rarely factory modded units that function as ST-Mouse. ST-Mouse uses pure gray code. You still need logic buffers connected to the trackball outputs. ST-mode uses vertical A/B inputs on left/right joystick; horizontal A/B inputs on up/down joystick. CX-22 has half the precision of ST mouse because one side of the vertical and horizontal gray code gets replaced with a directional key. Joyleft and Joyup are keyed and determine the direction of the last increment. Joyright and Joydown oscillate back and forth when the trackball is in motion. Again the horizontal inputs on the joystick indicate vertical movement, and the vertical inputs on the joystick indicate horizontal movement.

 

Sorry I don't have a schematic handy. If you're going to get a trackball, I recommend a CX-80 for superior build quality. Also a small number of CX-22 trackballs do not have a JS/TB switch and are permanently wired for joystick mode. If you get a CX-22, make sure it has a switch. Also Wiko trackballs are joystick mode only but could be modded to output gray code.

 

It is also notable that the CX-80 and CX-22 have 2.25 inch diameter, so for a cheap cosmetic mod, you can drop in a Regulation American style billiard ball. I bought an 8-ball from PoolDawgs to customize my CX-80.

I should have guessed if anyone would know how to build one of these it would be you Stardust . I had some interest from a guy wanting to place an order. Guess I'll have to disappoint him. I may recommend the CX-80 and pool ball idea to him.

 

I have the Atari 5200 Trakball which I like pretty well. Haven't bothered to get one for the 2600\7800 due to lack of games but maybe someday...

[Andromeda Stardust]

I should have guessed if anyone would know how to build one of these it would be you Stardust . I had some interest from a guy wanting to place an order. Guess I'll have to disappoint him. I may recommend the CX-80 and pool ball idea to him.

 

I have the Atari 5200 Trakball which I like pretty well. Haven't bothered to get one for the 2600\7800 due to lack of games but maybe someday...

The arcade trackballs start at like $60 plus you have to add supporting circuitry. If I wanted, I could trace my CX-80 (functions same as CX-22) and crank out a schematic, then order components on Digikey to assemble one, but the trackball controller is nearly perfect as is, so I don't see myself going out of my way to build one unless I was building an arcade cab or something.

 

I did buy a Sega Power Sports trackball last year that's ripe for modding. The thing is about useless in it's current form and only supported by three SMS games. I tried out that football game on my Genesis Everdrive which was bloody awful, spin the trackball like crazy and my character barely moved he was so slow. I didn't even bother trying the other ones. I bought it on Amazon for cheap after reading a rumor online that it could be made to work with Marble Madness for Genesis. I tried both the EA and Tengen versions to no avail. Neither game responded except with the switch in Joystick mode.

 

EDIT: 8-ball drops right in!

[7800fan]

I did buy a Sega Power Sports trackball last year that's ripe for modding. The thing is about useless in it's current form and only supported by three SMS games. I tried out that football game on my Genesis Everdrive which was bloody awful, spin the trackball like crazy and my character barely moved he was so slow. I didn't even bother trying the other ones. I bought it on Amazon for cheap after reading a rumor online that it could be made to work with Marble Madness for Genesis. I tried both the EA and Tengen versions to no avail. Neither game responded except with the switch in Joystick mode.

 

 

Sportspad controller in joystick mode works great on Atari games, once I got obscenely high score in Reactor from just one life. The controller in trackball mode only worked with SMS games and weren't supported beyond that, it is not surprising the controller didn't work well on Genesis games.

[jamm]

Did anyone ever attempt this?  I realize the CX22/CX80 are an option, but I'm envisioning a custom controller with a trackball, a paddle/spinner, and a couple of buttons that could be transported between 2600/7800/A8 and PC/Mac for use in MAME, etc.

[Andromeda Stardust]

8 hours ago, jamm said:

Did anyone ever attempt this?  I realize the CX22/CX80 are an option, but I'm envisioning a custom controller with a trackball, a paddle/spinner, and a couple of buttons that could be transported between 2600/7800/A8 and PC/Mac for use in MAME, etc.

you will need a switch array to swap between the input modes.