Here’s what it looks like put together:
You can see the Arduino shield, with connections to 3 pushbuttons and the slider on the top of the box. The cable coming out the right side is the usb cable and the midi connector is on the bottom.
Here’s a view of the left side:
You can see the Midi cable attached on the left side of this picture. I’m using a rubber band to hold the slider in the lowest not position. The tube coming out the side loops to a valve on the other side, then back into the case, then is jammed into the mouthpiece. I found blowing into a real mouthpiece provided a much better experience than blowing into a little tube.
Here’s a view of the other side:
I’m using an aquarium air control valve to allow some air to escape.