Work has continued! Current development is being done on a digispark, and I'm testing out the use of a BD679AG Darlington TO-126 instead of a mosfet, as it's much smaller and fits on the ideal size digispark add-on. Female 2.5mm sockets are on order from china, so I should be doing some initial board design on the hardware side, to get produced via dirty boards. If anyone could point me to software for making a circuit diagram, I would be grateful, as one has been requested in the comments.
Not much progress on the software side, as I'm a bit more interested in learning about board production right now, but I'll try to get on it soon!