Vail/VBand Adapter version 2

When building the first version of the vail/vband adapter, I ordered more than one of the Seeeduino boards. It's always good to have a spare. After some time operating the first version I noticed a few minor problems. None of these problems is a big deal, but as always when building something, I strive for perfection - at least in some respects. So when a friend of mine needed an adapter to get on vband, I decided to pass the old adapter over and build a second, improved one.

This is what I wanted to fix:

• The distribution of the sockets over left and right panel is suboptimal.
• I didn't like the unused switch.
• I would sometimes like to drive a small speaker instead of headphones.
• When operating vband, other "stations" come over the speakers connected to the computer while the side tone comes from the headphones connected to the vail/vband adapter. I would sometimes like to have all sound through the headphones.

Please note that none of the "problems" listed above is serious and none is in any way a problem of the adapter itself. They are all caused by my usage scenario and by the way I built the adapter. In addition, this second version is far more complex than the first one. So if you're reading this because you want to build such an adapter yourself, you should have a serious look at my first version.

So to start with, here's the schematics. You can see the additional audio input with separate volume control, better filtering of the square wave signal generated by the CPU and an audio amplifier built with an LM386. As with the first version, component choices were often a result of what was available in my spare part box. Clicking on the image will give you a larger version.

I also decided to create front and back panels with my 3D printer. This allows to have nice labels and a perfect dimensioning of the controls.