The code was pretty much ready at this point and required only a few touch ups here and there. The real issue now was to come up with a 3d printable CAD design that would house a custom PCB with all the parts I wanted on it in an elegant housing that wasn't completely different from what Acton had built. I liked the unusual Acton design language and wanted to keep the remote industrial looking.
I went through a large number of different design iterations until I finally settled on one that I actually liked.
The newer Bluetooth variant from a different supplier was a little too small for my hands.
It took a while to package the NRF, the Arduino, the potentiometer, the batteries and the DC/DC converter into a nice little, easy to hold and operate enclosure.
I took the design and created a PCB outline inside of Solidworks that I then exported as DXF and into KiCAD. I had never used KiCAD before, so this was a great reason to learn. I was unsatisfied with Eagle at this point so why not switch.
After the schematics where finished and the layout was routed, I fired up my PCB Mill and milled this double sided PCB. It turned out even better than I expected!
The Arduino Nano USB port is exposed at the back of the remote and can be used to upload new firmware. The battery latch is on the hand palm side of the remote so that the batts can't just fall out if you hold it in your right hand.
I managed to make my own battery contacts using an old spring that I rewound. That was surprisingly easy after I found a spring that was not stainless - because soldering to stainless steel is next to impossible.