After the setback from last weekend, I'm still waiting for new parts (additional LiPo backpack) and tools (cheap solder rework station) to arrive before jumping back into hardware. But I have made significant progress on the software side.
First up, here is a short video showing the project and where the software is at:
Also, here is a schematic I put together in frizzing (thought I'd give it a go - a bit limited when the exact part your after isn't there however). Note that rather than the LiPo Backpack I have used a basic breakout board for the charger chip as thats all I could find for Fritzing - should be reasonably straightforward to switch in the proper Lipo backpack however:
So, progress. The main application loop is now working, complete with periodic wake to record temperature in EEPROM, wake up when you move the nav stick, the bare bones of the home (temperature history) screen along with placeholders for the other initial ones I'll have, handling for moving from one screen to another, button/nav stick handling (including debounce and renounce), auto-sleep after 10 seconds inactivity, and places to insert the alarm checks and notifications. What remains is pretty much just filling in the specific screens. All updates pushed up to git once more.
One other little change of note is I modified the temperature reading code; previously it was throwing away the fractional portion. I'm now keeping it all and showing the temperature to a one decimal place - nice to watch it bounce up and down in response to a touch or drafts. The conversion of the 12 bit Celsius value to a value for display is handled by two (possibly to be combined) functions, so if anyone wants to add support for weird non-metric units (e.g. Rankine, Fahrenheit, Gas Mark) it would be easy enough to modify it there. Everywhere else I expect to just be showing relative values, so the specific scale won't matter.
Clearly I'm some way away from this being complete; final assembly of the circuit, completing the software and a case. Hoping to have it complete and documented within two weeks however.