"It was hard to tell from his video, but it didn't seem like all of the outputs could be switched from off to on. It looked like just the 4th output offered this switching."
Thanks for the question. It's so hard to explain everything in one video. All 4 channels can do switching. They are identical with the exception of channel 1. Channel 1 has a dimmable "side channel". Think of it as channel 1a.
"Wonder how well the arduino integrates in. If full control, you could connect the tron EL wire up to change colors."
I'm not going to say the Arduino part is an afterthought, but I haven't really used it yet. I have a mod that was briefly mentioned on the Spooky Pinball Podcast which is Arduino controlled. I'll be using the PIG for that mod.
There are two parts of this circuit. The first is to convert the games signals (inserts, GI, switches, flashers, etc) into a usable 5v logic signal.
The second part is to use that logic signal to turn things on and off. There's a little more to it, but that's really the basic explanation. What I did was put a detour between the logic out and logic in on the board. It's closed with jumpers so if it's never used, there is no harm in its being there.
If you remove the jumpers, you can insert an Arduino between the 5v in and 5v out in order to enhance the logic.
I hate to keep using TRON as an example, but it's just so easy. Imagine the "Quorra Multiball" light is on, and you put the ball into the scoop which also turns the switch on. You could use that "AND" logic with the Arduino to make a lit Quorra figurine start to pulse or flash or connect a servo and make her dance, who knows, the sky's the limit.
Here's the disclaimer: I have done no work with the Arduino and this board. It was just a thought that "if I had this board, I'd want to be able to insert an arduino right there to play around with it." So I built the interface but I have yet to play with it. I just wanted it to be easy to hack without having to hurt the board.
Thanks for the questions. Please keep them coming, I'll put it into a FAQ.