Been using Artisan quite happily for several months, great piece of open source software.
I presently use a Phidgets to get BT & ET, and I use an Arduino to control my heat gun.

I would like to send serial commands to the Arduino from button pushes on the screen. Of course, I figured out how to put buttons on the screen with custom commands, but how to ensure the commands go the Arduino (and not the Phidgets for example). I have not figured out any way of doing this, much less the best way. I keep searching the documentation, but found no answers yet. Any help would be appreciated.

I don't know the answer, but here's what I am wondering....

What do you have set up in the Extra Devices tab under Config? I see that Arduino 3_4 is an option, which makes me wonder if that would be where you would tell Artisan to look to the third and fourth inputs on the Phidget for your Arduino?

Good question about extra devices. Maybe I will give that a try. However, there are so many backdoors in Artisan, that I am reluctant to play with them since somebody out there, especially the author, must know the right way to do it.

Yeah, okay, I saw your post on the Artisan User Forum.

And I see that Marko has answered you there.

We have it figured out, thanks to Marko's quick feedback, and now I am just working out the details.
Ends up, the serial output goes to whichever device is the "main device", in this case for me its phidgets.
However, you can send the commands to an external program, which can then call the arduino.
That will work quite well for me.