Pi + Mumble + iCW

I commute to and from London 4 days a week.  There's an hour on the train each way.  I can only do so much CW training. What I need is something that connects to the phone to allow an easy CW QSO or two.  iCW is close, but doing that with a computer and all the gubbins is a bit too much to set up.  So I was thinking about this:

What sort of small black box can I make that will wifi to my phone hotspot, have a plug for key and headphones and micro USB for power (or have battery brick inside.)  It'd have just one big knob for channel selection and a couple of LEDs to indicate connection status.  

What would that be?  First thought is a Raspberry Pi Zero W with the headless Mumble client by Daniel Chote: https://github.com/dchote/talkiepi and a bit of work to interface a key and add a hacky headphone output.

So, that's the basic idea.  I'll see where experiments take me.   

1 response
Some kind of notification about which room you are in would be useful. Tone in? Can I recommend the Hi-Per-Mite as a nice circuit Also although this is strictly bloat a method of displaying sent text would help (decoded text is done at home by an arduino based text display). No reason why an audio output couldn't be used. Other than that the simpler the better