Well it looks more and more like a battery is needed for a standard spinner/paddle, could use the same pass-through connector like the Roller Controller but you'd have a second cord dangling out of the gamepad. I also read the whole coding side of reading a paddle is different than what the 2600 does to read inputs.
I guess a battery wouldn't be bad, you could always take it out for long stretches of not using it. Even the Roller Controller didn't have that many games using itself but those that did used it well, still less frequent use. Its also a trackball which is a tough device to incorporate in conjunction with other control options since they are usually a large component, on arcade cabs they are given a wide birth much like the Roller Controller design. I do like that a console even offered trackball since it was often something exclusive to arcades.
Its kind of odd the Coleco didn't get paddles except for the spinner on the SAC but the INTV didn't get them either. I guess paddles have had an irregular popularity over the years since there was a lot of paddles in the 70s on consoles, Atari and Commodore had them, but on the Nes it kind of petered off after the Arkanoid exclusive controller. For me its one of the fun aspects of 70-80s gaming but its definitely secondary to a primary means of control so its always going to be off to the side if not exclusive to the controller.
The Keypad aspect seems to have more origins in the 70s than the 80s since so many early consoles have keypads if not switches, I guess the 2600 could have ended up with a keypad which would have been a different experience historically. I guess its like a compact version of a keyboard so its cheaper than a big keyboard like the Odyssey 2 had but still it seems like it would add more cost to manufacturing the controllers and or console. Actually looking at PS4 gamepads recently I noticed all the added features which were neat but boy does make the controller expensive, same with the WiiU controller and its screen. Its a mystery why the keypad was thought to be such a killer feature making its way onto INTV, Coleco, 5200, 7800, etc. when arcade games didn't have them? Oh well, c'est la vie.
Sort of understand the keypad circuit in the sense I can see how only one key at a time can be pressed but still the path between the keypad, joystick, and 9-pin port eludes me. Tried tapping on my buddies shoulder for help but he's been busy with work and church stuff so I'm left with my own stupid brain lol.
Ramblin' aside I think I will build a prototype of this gamepad design but I have to raise some funds for it first by selling some extra consoles, slow tedious work cleaning them so I haven't got any out the door yet. Looked around my town for electronics component suppliers but all of them reside in the middle of Vancouver which I hardly ever go to so I'll likely order some online for delivery. So this is my last post on this subject till any real milestone is reached.