[Monitor Controls All, ThinCade: (part 5)]

I am fairly certain you can connect the arcade controls directly to the RPi GPIO headers and use the built-in audio jacks instead of the USB dongle.

Yes, you can do that. Keep in mind that I'm using a PI/zero which has no built in audio jacks. It is possible to get sound from the header but (needs to be set in the base code) it's noisy and support circuit is necessary for cleaner audio. It was much easier to just use the $0.99 usb audio dongle. As for the controls the USB interface is just easier to deal with as the GPIO header would need to be programed to and the USB device is pretty much plug and play and at $7.00 isn't that costly.

[Monitor Controls All, ThinCade: (part 5)]

I'm not really sure. I just know that it works with the set-up I show above.

 

I know my test rig uses a Pi2 and I'm powering it via the USB hub on the monitor with no problems, but I'm not using the 12 volt output from the monitor at the same time (meaning on my test rig).

 

I hope that helps.

[Arcade Buttons, ThinCade Project (Robotron 2084)]

I was going to suggest getting replacement buttons from Wico, but it appears they've gone out of business. There may still be a few parts distributors which stock the original translucent leaf spring buttons, but it appears you've managed to create a decent alternative.

 

I could have tried to locate leaf spring buttons, but that would have been to costly. I got the above switches (5 switches total) for $7.99 including shipping. That's only about $1.60 each. I doubt I would have been able to locate the real deal for that cost.

 

My total scratch build for Robotron can only cost about $250.00 total. Every little bit counts. If you get a chance be sure to read:

 

http://atariage.com/forums/blog/750/entry-15280-thincade-diy-arcade-project-part-1/

 

It lists out what I'm try to build and my constrains.