Hi Siobhan
Thanks for the kind words, and sorry for late response...I've been baking and programming prototype circuit boards pretty heavy over the last week.
I do hope to offer a USB solution of some type at some point. When building Roastmaster, of course, USB was not even a consideration, so I concentrated on building wireless solutions. But, USB is stuck in manufacturer's brains like glue, despite Bluetooth LE being a much better solution IMO. That was part of the the reason I began designing and building the custom hardware I mention for use with RM, along with the RBP protocol - to provide (in addition to temp sensing) a wireless "bridge" for USB devices.
Now...with the new iPad pros with USB C that may change. I will evaluate all of that once the hardware is in full beta testing. I have yet to look into exactly what is possible programmatically with Apple's implementation of the USB protocol. From the products coming to market, I assume is it fully open. Though, historically Apple has avoided that like the plague, so I remain skeptical. If it's open (and I hope that it is) it would be a straightforward proposition.
Either way...it's in future plans. Thanks for reaching out.
Danny